Efficiency
7
Availability
4
Manufacturing Carbon Footprint
2
Table 2: Solar Panel Criteria
We found cost per Watt to be the most important criterion because it is most directly related to the economic feasibility of the system. For this reason, we assigned cost per Watt a weight of ten. A system’s durability is also very important to its overall performance, as a greater system lifespan will
increase the amount of energy that it can produce. However, we decided that durability was less important than cost per Watt, giving it a weight of eight. Efficiency was not as important as the previous two criteria. In spite of this, it was still important that we meet a certain level of efficiency in order to generate enough power given the limited roof space. Therefore, we gave efficiency a weight of seven. The availability of a system was not very important due to the numerous solar panel options available, so it was given a weight of four. Finally, the carbon footprint was important from an environmental point of view, but weighting this category too heavily could lead us to selecting a solar power system that wasn't economically feasible, and therefore would not be implemented at all. For this reason, we gave the manufacturing carbon footprint a weight of only two. After performing this analysis on many different solar panels, we were left with a single number for each, representing how well each panel style met our criteria. We selected the top five as finalists for our recommended solar panel implementation.
3.3 Solar Panel Placement
Determining where to physically place the panels on the roof, as well as how to orient them, was important. This is because a panel’s orientation can have a large effect on the amount of solar energy it can gather and power it can generate. In order to decide how to optimally place the solar panels that were chosen, we created a number of placement scenarios. For each of our proposed scenarios, we determined a corresponding solar panel placement. Each placement has been carefully laid out attempting to meet the following criteria: maximum amount of power generation while still leaving room on the roof to walk. If at any point throughout the analysis, we felt that the given layout would not allow enough room to walk, we would remove the offending panels.
In order to generate the maximum amount of power, we wanted to place as many panels as possible at the optimal angle, without any of them being shaded between 9:00am and 3:00pm, the time
period of maximum sunlight.29. Aside from placing the panels outside of the shadowed area produced by the building, we also needed to ensure that the panels were not shaded by the row of solar panels in front of them. The minimum separation between the panels must be calculated using the worst case scenario sun position: when the sun is 30° above the horizon.
29 Lenardic, Denis. Solar radiation estimation and site analysis. http://www.pvresources.com/en/location.php.
30°
Θtilt
d
Solving for d in the above illustration yields the minimum separation distance between rows of solar panels without shading any of the panels at any point during the year. A solution for d can be found by using the equation below.
Figure 8: Depiction of the Sun Rays vs the Tilt of the Solar Panels
Calculating the minimum distance a row takes up is done using the following equation:
With this knowledge, we proceeded to break the roof up into a series of rectangles and determined the solar panel placement for each rectangle. We divided the width of each rectangle by the width of the solar panel and rounded down to get the number of solar panels for a given row. We then took the length of the rectangle and divided it by the minimum allowable distance for a row. This gave us the number of rows that we could have inside this rectangle. We did this for each rectangle, and then combined the results, making sure that there was enough walking space between the last row
of one rectangle and the first row of an adjacent rectangle. This process generated our optimal panel placement. To determine how we would wire the solar panels together, we followed the concept that we would wire solar panels in series that could potentially be shaded at the same time, and putting those rows in parallel with other rows. We calculated the maximum number of solar panels that could be placed in parallel by dividing the maximum current rating for the inverter by the peak current generated by the solar panels under ideal conditions. Rounding this number down gave us the maximum number of parallel rows.
Dividing the maximum voltage rating for the inverter by the peak voltage of the panels under ideal conditions and rounding down gave us the maximum number of solar panels that could be wired in series.
Based on the maximum number of panels that could be wired in series, we created rows of maximum length, going from north to south. This guaranteed that if there was shade, all of the panels in series would be shaded at the same time. We then placed as many adjacent rows in parallel as was allowed by the MAXparallel calculation, and wired them all to one inverter. We repeated this process until all solar panels were wired to an inverter. It is important to note that if shading occurs on a given solar panel, then current is unable to flow through it or any panels that are in series with this panel. This is important to consider when wiring up the panels, so that they are done in a way such that a small patch of shade won’t prevent multiple rows of panels from producing electricity.
3.4 Economic Feasibility of the Systems
The crux of this project was the determination of economic feasibility. In order to determine economic feasibility, one must do a thorough job of both understanding the mathematical analysis behind it and estimating the various parameters that are taken into account. This section will describe the mathematical analysis that we employed during our project as well as explain our methodology for the analysis. Later, during the economics section, we will present our choice of various parameters that go into the economic calculations along with our reasoning for their selection.
Initially, we gathered information about similar projects that have been done to determine economic feasibility. The Massachusetts Technology Collaborative (MTC) offers a Microsoft Excel spreadsheet that helps users determine the feasibility of solar panel installations.30 This spreadsheet was helpful because it accurately calculated the total rebates available in Massachusetts. It had a detailed depiction of cash flow analysis, and overall, cleanly presented the data. While being an excellent tool, we believed that there were many drawbacks to directly applying this economic analysis to Wesley United Methodist Church. The largest concern was that MTC’s analysis was specific to either a taxable commercial entity or a personal residence, while the Wesley United Methodist Church is neither, being a non-profit organization exempt from taxes. Rather than trying to modify what MTC had done, we decided to assume the relevant portions from their spreadsheet and use them as a basis for our own calculations. This allowed us to make a spreadsheet tailored specifically to the Wesley United Methodist Church. The spreadsheet that we made contained the following sections: Section 1: System Size and Cost Section 2: Installation and Fees
30 Non-Residential Rebate Calculator. Commonwealth Solar. http://www.masstech.org/SOLAR/Attachment%20A2-Non%20Residential%20Solar%20Rebate%20Calculator%20Only-070208.xls.
Section 3: System Life Expectancy
Section 4: Incentives and Rebates Section 5: Financing Section 6: Energy Generation and Usage Section 7: Worldwide Economic Factors Section 8: Results and Analysis The first section dealt with the scale of the system, the cost of the solar panels per Watt, and the cost of the inverter and other components. We chose to have the data entered in this way because by using cost per Watt as a primary variable, the economic analysis is more readily scalable to systems of various sizes. Until a company makes a final estimate, we feel it is best to analyze the data on a per Watt basis because other parameters can be changed to see how they affect the cost of the overall system. The end of Section 1 displays the total cost of the photovoltaic system components. The next section dealt with the cost of the installation and other associated fees. The largest contributor to this category was the installation cost per Watt. The most accurate way to determine an installation cost would be to get multiple estimates from different contractors. In the meantime, we have chosen to look at the installation cost on a per Watt basis because we can estimate it with a reasonable amount of certainty and because it is scalable to different system sizes. After taking into account electrical inspection costs and other fees, section two calculates the total cost of installation and fees.
Section three dealt with the system’s lifespan and maintenance costs. The system life expectancy is an important factor because it determines the amount of time the solar panel will be producing energy. A longer life expectancy generates a better net present value (the sum of future cash flows discounted to the present value) and a better return on investment. This section also deals with system degradation, as each year solar systems put out slightly less energy than they did before. This is
due to the system slowly breaking down. Maintenance costs, as well as a maintenance cost adjustor were also included in this section. The maintenance cost adjustor allowed us to predict how much maintenance costs will increase over the lifetime of the system. The next section, incentives and rebates, came primarily from MTC’s spreadsheets for determining economic feasibility. Its parameters are the system size, whether or not the building is a public building, and whether or not the components are manufactured in Massachusetts. It uses these factors to determine the total system rebate. This section also takes the Renewable Energy Credit (REC) price per Watt and an accompanying adjustor for this price and estimates the revenue that will be generated each year from renewable energy credits. At the end of this section, we were able to calculate the total cost of the solar panel system, by taking into account the cost of the components, the cost of installation and fees, and the total rebate received. The section on financing allows the user to input the down payment percentage, which is useful to help the church determine how the size of the down payment affects the system’s overall economic feasibility. The interest rate and loan period are also inputs in this section. With this data, we were able to calculate the size of the down payment and the monthly payment. The next section, energy generation and usage, allows us to calculate how much energy will be produced from the solar panels. There are fields to input the average daily insolation per m2 for each month. Using this data, along with the system efficiency, we can determine the total amount of energy expected to be generated in the system’s first year. Using the degradation factor from Section 3, we can then determine the expected energy generation for each year of the system’s life expectancy.
The last section, analysis, takes information from the previous sections to compute typical economic values such as net present value, the breakeven point, and cash flow. The yearly cash flow (a value which changes from year to year) is calculated by taking the amount of money saved in the year, from both RECs and saved energy costs, and subtracting the cost of the loan. Net present value is
Tuesday, October 13, 2009
We decided that the best metric for evaluating a solar system was the cost per Watt produced by the panel. Naturally, the lower this number, the greater energy production that can be purchased for the same dollar amount. This criterion will lead to a better return on investment and fewer years until the church recovers their initial capital. We determined that the second most important criterion for determining the feasibility of a solar panel system was its durability. Less durable systems would incur higher maintenance costs and exhibit a shorter lifetime of operation. The longer the solar system lasts the more energy the church will be able to obtain from it. We decided that the efficiency rating of the photovoltaic panel was important because it is directly related to the maximum power a system using the panel could produce. The church had a set amount of space available for a solar installation. The higher the efficiency of the solar system, the higher the amount of power we could get from a system covering the same amount of space. The availability of a certain solar technology also factored into our analysis of feasibility. There are long waiting lists for some of the newer solar panel technologies, such as thin film solar panels. For this criterion, there was a trade-off between only looking at what is readily available and waiting for a better technology to become available. The weight of the solar panel system was important. The roof at Wesley United Methodist Church is able to support 35lb per square foot, so any system heavier than that was disregarded.
Finally, we considered the carbon footprint of the manufacturing process as we analyzed solar panel feasibility. Some manufacturing processes place a larger burden on the environment than others. Because one of the greatest benefits to using renewable technologies is the positive effects they have on the environment, this was something to consider. It was not, however, as important as some of the previous criteria because the most important part of this study was to find a solar solution that would be economically feasible. We would not recommend proceeding with a solar panel solution that caused a
negative cash flow, so it was more important that we found a solution that is economically feasible than that we found the most environmentally friendly solution. Certainly, any renewable energy source that gets implemented is significantly better for the environment than continuing to use nonrenewable resources for energy production. In order to determine which solar panels were best suited for this project, we first discarded any that were too heavy for the roof to support. Next, we performed a competitive analysis on the remaining panels. Competitive analysis is a process that can aid in making decisions when there are many factors to consider. First, we created a list of criteria and weights, which can be seen in the table below. Weights were assigned to each of the criteria, based on the decided importance of each. The different solar solutions were then rated in each of these categories. Finally, each weight was multiplied by its respective rating and then all of these results were tallied for each solution. At the end of this process, each solution was given a number representing its overall score.
Criteria
Weight
$/Watt
10
Durability
Finally, we considered the carbon footprint of the manufacturing process as we analyzed solar panel feasibility. Some manufacturing processes place a larger burden on the environment than others. Because one of the greatest benefits to using renewable technologies is the positive effects they have on the environment, this was something to consider. It was not, however, as important as some of the previous criteria because the most important part of this study was to find a solar solution that would be economically feasible. We would not recommend proceeding with a solar panel solution that caused a
negative cash flow, so it was more important that we found a solution that is economically feasible than that we found the most environmentally friendly solution. Certainly, any renewable energy source that gets implemented is significantly better for the environment than continuing to use nonrenewable resources for energy production. In order to determine which solar panels were best suited for this project, we first discarded any that were too heavy for the roof to support. Next, we performed a competitive analysis on the remaining panels. Competitive analysis is a process that can aid in making decisions when there are many factors to consider. First, we created a list of criteria and weights, which can be seen in the table below. Weights were assigned to each of the criteria, based on the decided importance of each. The different solar solutions were then rated in each of these categories. Finally, each weight was multiplied by its respective rating and then all of these results were tallied for each solution. At the end of this process, each solution was given a number representing its overall score.
Criteria
Weight
$/Watt
10
Durability
. A five year warranty provided by the installer of the system for defective workmanship. . A two
20 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
. A five year warranty provided by the installer of the system for defective workmanship. . A two years product and 20 years performance warranty on the system modules. . A five year warranty on the system mounting. . A ten year warranty on the power inverters.
Other Requirements:
. The equipment installed must be new. . The equipment installed must meet the Underwriters Laboratory standard 1703
. All modules, inverters, and production meters must be on the California Energy Commission’s list of eligible renewable energy equipment. . All photovoltaic projects must have a dedicated production meter . Systems over 10kw must have a production tracking system (PTS).
A solar-energy system purchased for the principal residence of an individual is fully exempt from Massachusetts sales tax. In addition, solar-energy systems purchased for commercial, industrial, or residential use are exempt from property tax over their first twenty years. A 15% tax credit up to $1000 against personal state income tax is available to any owner or tenant for the purchase and installation of a solar-energy system in their primary residence. The system installed must be new, in compliance with all performance and safety standards, and be expected to last at least five years. Renewable energy credits (RECs) are based on the environmental attributes associated with the generation of electricity. They do not have to do with the electricity itself, but the means by which the electricity was generated. Renewable Energy credits exist for two primary reasons. For one, the state government sets Renewable Portfolio Standards on utility companies. These require a certain amount of electricity produced by these companies to be from renewable sources. Utilities that do not produce enough electricity from renewable sources may buy RECs from those who produce energy from renewable sources. RECs may also be sold to consumers who want to be sure that the electricity that they are consuming comes from renewable source. RECs may be sold to various state and nationwide organizations. Current prices for these credits range from .5 cents a kilowatt hour to 5.5 cents a kilowatt hour.
Net metering is an electricity agreement between a consumer and their electricity provider which allows the consumer to offset some, or all, of their energy cost by running the electric meter
backward via producing a surplus amount of energy. Running the electricity meter backward occurs when a consumer is producing more energy than he or she is currently utilizing.21 As a result, in any month with a positive net difference, the customer may choose to receive a credit equal to the average monthly market price of generation per kilowatt hour. The utility company cannot impose special fees on net metering customers.22 The state of Massachusetts currently enforces all investor-owned utilities to offer net metering but does not require municipal utilities to abide by the same standard.
21 CalFinder. What is net metering? Retrieved September, 2008, from http://solar.calfinder.com/blog/solar-information/what-is-net-metering/
22 DSIRE. Massachusetts Incentives for Renewable Energy. Retrieved November, 2008, from http://www.dsireusa.org/documents/Incentives/MA01R.htm
23 DSIRE. Massachusetts Incentives for Renewable Energy: Net Metering. Retrieved November, 2008, from http://www.dsireusa.org/library/includes/incentive2.cfm?Incentive_Code=MA01R&State=MA&CurrentPageID=1
The current standard for net metering was enacted on July 2, 2008, and is applicable to residential, commercial, nonprofit, industrial, school, institutional, agricultural and governmental sectors.23 Net metering customers are grouped into three classes (I, II and III) which are determined by system size. The most common size class for residential and a small commercial is Class 1. Class 1 describes any system which is less than or equal to 60kW. The second and third class apply to systems which are 1MW and 2MW, respectively. For Class 1 solar installations, credits may be carried forward from month to month indefinitely. These customers may also choose to transfer the credits earned to another customer on the same utility.
2.4.2 Factors in Determining Economic Feasibility
The final result of this project will be the determination of whether or not the installation of a solar panel system is economically feasible on Wesley United Methodist Church. Before we proceed with economic analysis of the solar panel system at Wesley United Methodist Church, we must outline what factors determine economic feasibility. The startup costs, operating costs, revenue projections, and financing options will all need to be considered.
In this solar panel installation, the start up costs will include product cost, installation cost, and the cost of inspection and certification. The product cost will include all of the various hardware components of a solar power system, including the actual solar panels, the frames to mount them on, the inverter to convert the DC power to AC, and the grid tie system which will allow it to connect to the power grid. There will also be the cost of a professional installation, as this is a requirement for the MTC grant. Finally, there is the cost of inspection and certification, which is also required to receive the aforementioned grant. All of these costs will be reduced by the grants and incentives outlined in the previous section to determine the overall startup cost. After the solar panels are installed and generating electricity, there is an operational cost that goes along with maintaining them. Solar retailers often give information about the maintenance cost of solar panels, which includes any maintenance or repairs or replacement of damaged solar panels. Even smaller costs, such as the cost of shoveling snow off of the solar panels during the winter would fall under this category.
The money generated from the solar panels would ideally offset the costs mentioned above. Money generated from solar panels can be broken into three main categories: energy saved, energy sold-back, and renewable energy credits. The primary category, energy saved, will be the difference in cost between the electric bill with the solar panels installed and what the electric bill would have been without them installed. In the simplest scenario, this would be the number of kWh generated that does not exceed the amount used multiplied by the cost per kWh. The next category, energy sold back to the electric company, would be any amount of electricity generated by the solar system that exceeded energy usage and could be sold back to the electric company. The final way to profit from solar panels is through the sale of renewable energy credits to other corporations. Corporations are regulated by the government to meet a certain quota for the use of renewable energy. Some generate their own
renewable energy; however, others buy credits in lieu of generating it themselves. These credits have their own market, and the proceeds from of the sale of credits may be in addition to the money received from the previous two categories. The final consideration when analyzing the feasibility of such a project is the available financing. Solar panel systems generally require a large capital investment. Much of this cost is typically paid by borrowing from banks or investors. Important considerations when looking for financing are the interest rate, the duration of the loan, the monthly payment, and the required down payment.
2.5 Similar Case Studies
There are many factors to consider when analyzing the feasibility of different solar systems for Wesley United Methodist Church. We investigated a number of case studies to evaluate the factors in a feasibility study in the domain of renewable energy.
2.5.1 Holy Name Wind Power Feasibility Study
The Holy Name wind power feasibility study investigated the feasibility of installing a wind turbine at Holy Name high school.24 The main task of the project was broken into various parts. First, site data was gathered, including wind speeds, current energy usage and property characteristics. Using this data, a number of sites were proposed and compared against a set of heuristics to determine the best possible location. Then, based on the size of the installation that would be required to provide an adequate amount of electricity, a list of possible turbines was made. These turbines were then compared against each other to find the best possibility. Also, a mathematical model was created to determine the economic feasibility and break-even points using different financing options. Five, seven, ten, and twenty year loans were simulated and return on investment figures were calculated for each simulation. Grants, net metering, energy certificates, tax incentives, and different loan options were all
24 Foley, B., Forbes, T., Jensen, H., & Young, A. (2006). Holy Name High School Wind Turbine Feasibility Study. WPI Library: http://www.wpi.edu/Pubs/E-project/Available/E-project-121306-104131/
explored. The report concluded that 60 to 70% of the school's electric bill could be saved through the installation of a turbine. Although this project did not focus on solar panels, there are many aspects of it that are applicable to any renewable energy feasibility study. The process of determining feasibility itself, from site analysis to comparing different technologies to creating an economic model, is similar regardless of which renewable source is considered. Also, many of the incentives for renewable energy are similar for both wind and solar systems.
2.5.2 Solar Feasibility Study of a Learning Center at WPI
The Feasibility Study of a Solar Learning Lab at WPI was an incredibly insightful case study due to its similar location to our target and the use of photovoltaic panels.25 The goal of this Interactive Qualifying Project was to determine the feasibility of acquiring a Solar Learning Lab somewhere on the WPI campus. A Solar Learning Lab would give the students of WPI the ability to study the effects of solar energy without leaving campus. While the objective of this project was not to generate power for the school, the similarities between this project and ours gave us a good idea of the steps we would have to take to determine if the meteorological conditions were acceptable for using photovoltaics.
25 Wailgum, J., Ledue, J., Chapman, J., & Al-Beik, H. (2003). Feasibility study of a solar learning lab at WPI. WPI Library: http://library.wpi.edu/cgi-bin/Pwebrecon.cgi?BBID=251492
26 Heliotronics. Heliotronics Data Acquisition Systems. http://www.heliotronics.com
A Solar Learning Lab is the term used to describe a photovoltaic system integrated with a Heliotronics educational monitoring system. 26 The entire system is used to bring current solar information to a computer display where students are then capable of manipulating the data to generate graphs and plot trend lines. A Solar Learning Lab is designed to provide students with a hands-on understanding of how photovoltaics work without purchasing a large system.
One of the first tasks that the IQP group undertook was to determine an acceptable location for their solar panels. This meant that each possible location must agree to a set of criteria and is ranked on how well it matched. Several considerations were safety, space and availability, accessibility, security, connectivity, sunlight exposure, and grid tying considerations. The final location chosen was "Daniels Hall". This building fit each of the criteria and gave the best possible outcome for the project. The decision process of choosing a location was very enlightening and paralleled our own process. The next step of the group was to establish their projected results. The installation process was reviewed many times to determine what spot on the roof of Daniels Hall provided the easiest installation. Several experts from various contracting companies were brought in to provide their detailed analysis on the location and installation situation. This process established the cost of the Solar Learning Lab as well as the installation and maintenance, which enabled the group to generate a cost analysis of their project. The last remaining step was to establish an acceptable marketing campaign that would sell WPI on their idea. The group presented their project's financial aspects, academic benefits, and environmental friendly appearance. Each subject was presented in a fair and unbiased manner that depicted the strengths and weaknesses of the project.
2.5.3 Janssen Ortho LLC Solar Power Feasibility Study
Janssen Ortho LLC is a subsidiary of Johnson and Johnson based in Puerto Rico and had an IQP team evaluate the feasibility of a solar panel installation27. This project discussed the history of Janssen Ortho LLC and the importance of being environmentally friendly to the company (17). Johnson and
27 Sands, E., Moussa, O., Meagher, G., & Lemaire, J. (2004). Solar Energy at Janssen Ortho LLC. WPI Library: http://library.wpi.edu/cgi-bin/Pwebrecon.cgi?BBID=253817
Johnson follow a credo, part of which states that it will be a leader in helping the environment. Janssen Ortho LLC consumes 33 million kWh yearly, certainly too much to be generated entirely from solar power. The project group consulted with Powerlight Corporation, a world leader in solar installations, and eventually recommended a pilot installation. The pilot system would product 101kWp (kilowatts peak), less than 1% of Janssen Ortho’s power consumption; however it would demonstrate to the community that they were interested in alternative energy. This group also proposed a possible larger scale solution that would involve the construction of a solar panel mounting structure over the parking lots. Due to the high expense of building on top of the parking lots, the group only recommended pursuing this if they were able to get 70% government aid. The group also created brochures for employees and for the community to spread information regarding the benefits of solar projects.
3. Methodology
In order to determine the overall feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church, we divided this task into five sections. The first section, site analysis, was concerned with obtaining the physical layout of the roof space suitable for panel placement, as well as determining relevant meteorological data that was needed for energy calculations. The second section, possible solar panels and placements, dealt with determining the criteria and system that would be used to select the best panel style for the church. The third section investigated what the effect of different orientations and configurations of the panels would have on the amount of energy that could be produced. Economic feasibility of the systems, the fourth section, investigated what economic factors and assumptions should be used in order to create an accurate economic model of the solar panel system as an investment vehicle. In the final section, social implications, our objective was to determine what social factors might come into play that could help or hinder the support for the installation of a photovoltaic system.
3.1 Site Analysis
Given the relationship between the sunlight available in a region and a solar cell’s energy output, site analysis was one of the greatest influences on the feasibility of a photovoltaic project. Given the church’s geographical location in Worcester, Massachusetts, several factors were considered. Each factor dealt primarily with the sunlight available or the geographical layout of the designated site. Factors such as location, average sunlight, daily shadows, obtrusive objects, and structural positioning combined to form the project’s site analysis. To obtain the data needed to form our site analysis, the project was divided into a number of domains. The first dealt primarily with the meteorological conditions of Worcester. This domain sought to answer the question of how much sunlight is available, as well gather any information that would ease the calculation of how much energy can potentially be
produced by an array of solar cells. The second domain dealt with the structural layout of the roof space at the Wesley United Methodist Church. This domain was responsible for determining where solar panels could be placed by taking shadows, obtrusive objects, and structural support into consideration. The third domain consisted of gathering and summarizing the current energy usage of the church. This data could be used to form estimates about how much money could be saved through the energy generated by the installation of a solar panel system. The last domain, concerning the installation of solar panels, dealt with determining what factors would come into play when installing the panels onto the roof, as well as integrating the system into the electrical grid.
3.1.1 Meteorological Analysis
Gathering and summarizing meteorological data was a vital aspect for creating the site analysis. Obtaining meteorological data is done with relative ease these days. One of the greatest resources of weather data is provided by GAISMA28. It includes information such as monthly atmospheric clearness as well as sunrise and sunset durations. Most importantly, GAISMA offers a monthly insolation calculation. Insolation is a composite measurement that summarizes the amount of solar radiation that an area receives. The insolation value is a numerical value that represents the average kWh/m2/day in a given month. These values are exceptional tools that encapsulate various meteorological events; for example, this calculation encompasses the change in sunlight due to cloudy or partially cloudy days. The result is a value that describes the amount of solar radiation (sunlight) available in a given area per day. This average was used in the calculation of how much energy would be produced by a given solar panel. This allowed for relatively accurate calculations of future energy production which was essential for determining when a return on investment could be realized.
28 GIASMA [Online] www.giasma.com
3.1.2 Layout of Roof Space
To determine the layout of the roof space, we took preliminary measurements of the roof. With these basic dimensions, we were able to calculate a best-case scenario for mounting solar panels. This best-case scenario acted as an upper bound on the size of the system that could be installed. With the preliminary measurements, we were also able to obtain a set of plans for the roof, with detailed dimensions. From this, a simpler and smaller-sized CAD drawing was created using the set of plans and the measurements taken on the roof. However, the primary problem with taking our measurements at only one time of day was that they didn’t include all possible shadowed areas. Another problem encountered was that we didn’t initially record the locations of any other possible shadows, such as trees or the chimney, which could cast a shadow over several panels at different times of day. Our research on different panels showed that panels should not be partially shaded. It was therefore decided that we would visit the site at different times of day to take detailed measurements of where shadows fell. This allowed us to create a printed plan of the roof space, including areas representing the shaded portions of the roof, using a software modeling program. With this information, a more accurate calculation of the possible area suitable for a photovoltaic system was made. We also determined the necessary spacing of an array using different panels, to figure out how many panels could effectively fit onto the roof’s surface. Inter-panel spacing was important because tilting the panels for the optimum angle of the sun could potentially cause them to cast shadows onto each other. Using trigonometric calculations, we found the spacing necessary between panels to avoid these types of shadows, as well as determined the maximum number of panels as a result of this spacing. This maximum number of panels allowed us to determine how much power could be harnessed in each of our panel configurations.
3.1.3 Energy Usage
We found it necessary to gather previous energy data from the church in order to gain a better understanding of how a solar panel system would affect the overall amount of energy that the church could save. Previous electric bills contained the number of kilowatt hours consumed by the church, as well as the price paid for these hours. Using this data, we were able to summarize the trends in energy usage over the course of the year, and more importantly, compare this energy data to the estimated energy that could be produced by a solar panel installation. The electrical purchasing history of the church also gave us an initial cost of electricity, which was very useful in our economic analysis.
3.1.4 The Installation Process
Researching the installation process was another important aspect of the site analysis. This involved contacting local installers and analyzing the Worcester Code Enforcement to better understand the electric codes relevant to the installation of a photovoltaic system. In addition to this, we contacted National Grid, the power supplier for the church, to find any other regulations pertaining to connecting the church’s solar panel system to the electrical grid. It was also important to determine the nature of the materials that the roof was composed of, and what methods of mounting the panels would work best on these surfaces. Research was done to create a contact list of local installers who would be able to install a system if it were found to be feasible.
3.2 Analysis of Solar Panels and Systems
In our pursuit of the most economical solar panel solution for Wesley United Methodist Church, we came across many possible options for panels, inverters, and other equipment, each with their own costs and benefits. In order to determine which solution was optimal, we enumerated a list of criteria that was used to evaluate each solution.
We decided that the best metric for evaluating a solar system was the cost per Watt produced by the panel. Naturally, the lower this number, the greater energy production that can be purchased for the same dollar amount. This criterion will lead to a better return on investment and fewer years until the church recovers their initial capital. We determined that the second most important criterion for determining the feasibility of a solar panel system was its durability. Less durable systems would incur higher maintenance costs and exhibit a shorter lifetime of operation. The longer the solar system lasts the more energy the church will be able to obtain from it. We decided that the efficiency rating of the photovoltaic panel was important because it is directly related to the maximum power a system using the panel could produce. The church had a set amount of space available for a solar installation. The higher the efficiency of the solar system, the higher the amount of power we could get from a system covering the same amount of space. The availability of a certain solar technology also factored into our analysis of feasibility. There are long waiting lists for some of the newer solar panel technologies, such as thin film solar panels. For this criterion, there was a trade-off between only looking at what is readily available and waiting for a better technology to become available. The weight of the solar panel system was important. The roof at Wesley United Methodist Church is able to support 35lb per square foot, so any system heavier than that was disregarded.
. A five year warranty provided by the installer of the system for defective workmanship. . A two years product and 20 years performance warranty on the system modules. . A five year warranty on the system mounting. . A ten year warranty on the power inverters.
Other Requirements:
. The equipment installed must be new. . The equipment installed must meet the Underwriters Laboratory standard 1703
. All modules, inverters, and production meters must be on the California Energy Commission’s list of eligible renewable energy equipment. . All photovoltaic projects must have a dedicated production meter . Systems over 10kw must have a production tracking system (PTS).
A solar-energy system purchased for the principal residence of an individual is fully exempt from Massachusetts sales tax. In addition, solar-energy systems purchased for commercial, industrial, or residential use are exempt from property tax over their first twenty years. A 15% tax credit up to $1000 against personal state income tax is available to any owner or tenant for the purchase and installation of a solar-energy system in their primary residence. The system installed must be new, in compliance with all performance and safety standards, and be expected to last at least five years. Renewable energy credits (RECs) are based on the environmental attributes associated with the generation of electricity. They do not have to do with the electricity itself, but the means by which the electricity was generated. Renewable Energy credits exist for two primary reasons. For one, the state government sets Renewable Portfolio Standards on utility companies. These require a certain amount of electricity produced by these companies to be from renewable sources. Utilities that do not produce enough electricity from renewable sources may buy RECs from those who produce energy from renewable sources. RECs may also be sold to consumers who want to be sure that the electricity that they are consuming comes from renewable source. RECs may be sold to various state and nationwide organizations. Current prices for these credits range from .5 cents a kilowatt hour to 5.5 cents a kilowatt hour.
Net metering is an electricity agreement between a consumer and their electricity provider which allows the consumer to offset some, or all, of their energy cost by running the electric meter
backward via producing a surplus amount of energy. Running the electricity meter backward occurs when a consumer is producing more energy than he or she is currently utilizing.21 As a result, in any month with a positive net difference, the customer may choose to receive a credit equal to the average monthly market price of generation per kilowatt hour. The utility company cannot impose special fees on net metering customers.22 The state of Massachusetts currently enforces all investor-owned utilities to offer net metering but does not require municipal utilities to abide by the same standard.
21 CalFinder. What is net metering? Retrieved September, 2008, from http://solar.calfinder.com/blog/solar-information/what-is-net-metering/
22 DSIRE. Massachusetts Incentives for Renewable Energy. Retrieved November, 2008, from http://www.dsireusa.org/documents/Incentives/MA01R.htm
23 DSIRE. Massachusetts Incentives for Renewable Energy: Net Metering. Retrieved November, 2008, from http://www.dsireusa.org/library/includes/incentive2.cfm?Incentive_Code=MA01R&State=MA&CurrentPageID=1
The current standard for net metering was enacted on July 2, 2008, and is applicable to residential, commercial, nonprofit, industrial, school, institutional, agricultural and governmental sectors.23 Net metering customers are grouped into three classes (I, II and III) which are determined by system size. The most common size class for residential and a small commercial is Class 1. Class 1 describes any system which is less than or equal to 60kW. The second and third class apply to systems which are 1MW and 2MW, respectively. For Class 1 solar installations, credits may be carried forward from month to month indefinitely. These customers may also choose to transfer the credits earned to another customer on the same utility.
2.4.2 Factors in Determining Economic Feasibility
The final result of this project will be the determination of whether or not the installation of a solar panel system is economically feasible on Wesley United Methodist Church. Before we proceed with economic analysis of the solar panel system at Wesley United Methodist Church, we must outline what factors determine economic feasibility. The startup costs, operating costs, revenue projections, and financing options will all need to be considered.
In this solar panel installation, the start up costs will include product cost, installation cost, and the cost of inspection and certification. The product cost will include all of the various hardware components of a solar power system, including the actual solar panels, the frames to mount them on, the inverter to convert the DC power to AC, and the grid tie system which will allow it to connect to the power grid. There will also be the cost of a professional installation, as this is a requirement for the MTC grant. Finally, there is the cost of inspection and certification, which is also required to receive the aforementioned grant. All of these costs will be reduced by the grants and incentives outlined in the previous section to determine the overall startup cost. After the solar panels are installed and generating electricity, there is an operational cost that goes along with maintaining them. Solar retailers often give information about the maintenance cost of solar panels, which includes any maintenance or repairs or replacement of damaged solar panels. Even smaller costs, such as the cost of shoveling snow off of the solar panels during the winter would fall under this category.
The money generated from the solar panels would ideally offset the costs mentioned above. Money generated from solar panels can be broken into three main categories: energy saved, energy sold-back, and renewable energy credits. The primary category, energy saved, will be the difference in cost between the electric bill with the solar panels installed and what the electric bill would have been without them installed. In the simplest scenario, this would be the number of kWh generated that does not exceed the amount used multiplied by the cost per kWh. The next category, energy sold back to the electric company, would be any amount of electricity generated by the solar system that exceeded energy usage and could be sold back to the electric company. The final way to profit from solar panels is through the sale of renewable energy credits to other corporations. Corporations are regulated by the government to meet a certain quota for the use of renewable energy. Some generate their own
renewable energy; however, others buy credits in lieu of generating it themselves. These credits have their own market, and the proceeds from of the sale of credits may be in addition to the money received from the previous two categories. The final consideration when analyzing the feasibility of such a project is the available financing. Solar panel systems generally require a large capital investment. Much of this cost is typically paid by borrowing from banks or investors. Important considerations when looking for financing are the interest rate, the duration of the loan, the monthly payment, and the required down payment.
2.5 Similar Case Studies
There are many factors to consider when analyzing the feasibility of different solar systems for Wesley United Methodist Church. We investigated a number of case studies to evaluate the factors in a feasibility study in the domain of renewable energy.
2.5.1 Holy Name Wind Power Feasibility Study
The Holy Name wind power feasibility study investigated the feasibility of installing a wind turbine at Holy Name high school.24 The main task of the project was broken into various parts. First, site data was gathered, including wind speeds, current energy usage and property characteristics. Using this data, a number of sites were proposed and compared against a set of heuristics to determine the best possible location. Then, based on the size of the installation that would be required to provide an adequate amount of electricity, a list of possible turbines was made. These turbines were then compared against each other to find the best possibility. Also, a mathematical model was created to determine the economic feasibility and break-even points using different financing options. Five, seven, ten, and twenty year loans were simulated and return on investment figures were calculated for each simulation. Grants, net metering, energy certificates, tax incentives, and different loan options were all
24 Foley, B., Forbes, T., Jensen, H., & Young, A. (2006). Holy Name High School Wind Turbine Feasibility Study. WPI Library: http://www.wpi.edu/Pubs/E-project/Available/E-project-121306-104131/
explored. The report concluded that 60 to 70% of the school's electric bill could be saved through the installation of a turbine. Although this project did not focus on solar panels, there are many aspects of it that are applicable to any renewable energy feasibility study. The process of determining feasibility itself, from site analysis to comparing different technologies to creating an economic model, is similar regardless of which renewable source is considered. Also, many of the incentives for renewable energy are similar for both wind and solar systems.
2.5.2 Solar Feasibility Study of a Learning Center at WPI
The Feasibility Study of a Solar Learning Lab at WPI was an incredibly insightful case study due to its similar location to our target and the use of photovoltaic panels.25 The goal of this Interactive Qualifying Project was to determine the feasibility of acquiring a Solar Learning Lab somewhere on the WPI campus. A Solar Learning Lab would give the students of WPI the ability to study the effects of solar energy without leaving campus. While the objective of this project was not to generate power for the school, the similarities between this project and ours gave us a good idea of the steps we would have to take to determine if the meteorological conditions were acceptable for using photovoltaics.
25 Wailgum, J., Ledue, J., Chapman, J., & Al-Beik, H. (2003). Feasibility study of a solar learning lab at WPI. WPI Library: http://library.wpi.edu/cgi-bin/Pwebrecon.cgi?BBID=251492
26 Heliotronics. Heliotronics Data Acquisition Systems. http://www.heliotronics.com
A Solar Learning Lab is the term used to describe a photovoltaic system integrated with a Heliotronics educational monitoring system. 26 The entire system is used to bring current solar information to a computer display where students are then capable of manipulating the data to generate graphs and plot trend lines. A Solar Learning Lab is designed to provide students with a hands-on understanding of how photovoltaics work without purchasing a large system.
One of the first tasks that the IQP group undertook was to determine an acceptable location for their solar panels. This meant that each possible location must agree to a set of criteria and is ranked on how well it matched. Several considerations were safety, space and availability, accessibility, security, connectivity, sunlight exposure, and grid tying considerations. The final location chosen was "Daniels Hall". This building fit each of the criteria and gave the best possible outcome for the project. The decision process of choosing a location was very enlightening and paralleled our own process. The next step of the group was to establish their projected results. The installation process was reviewed many times to determine what spot on the roof of Daniels Hall provided the easiest installation. Several experts from various contracting companies were brought in to provide their detailed analysis on the location and installation situation. This process established the cost of the Solar Learning Lab as well as the installation and maintenance, which enabled the group to generate a cost analysis of their project. The last remaining step was to establish an acceptable marketing campaign that would sell WPI on their idea. The group presented their project's financial aspects, academic benefits, and environmental friendly appearance. Each subject was presented in a fair and unbiased manner that depicted the strengths and weaknesses of the project.
2.5.3 Janssen Ortho LLC Solar Power Feasibility Study
Janssen Ortho LLC is a subsidiary of Johnson and Johnson based in Puerto Rico and had an IQP team evaluate the feasibility of a solar panel installation27. This project discussed the history of Janssen Ortho LLC and the importance of being environmentally friendly to the company (17). Johnson and
27 Sands, E., Moussa, O., Meagher, G., & Lemaire, J. (2004). Solar Energy at Janssen Ortho LLC. WPI Library: http://library.wpi.edu/cgi-bin/Pwebrecon.cgi?BBID=253817
Johnson follow a credo, part of which states that it will be a leader in helping the environment. Janssen Ortho LLC consumes 33 million kWh yearly, certainly too much to be generated entirely from solar power. The project group consulted with Powerlight Corporation, a world leader in solar installations, and eventually recommended a pilot installation. The pilot system would product 101kWp (kilowatts peak), less than 1% of Janssen Ortho’s power consumption; however it would demonstrate to the community that they were interested in alternative energy. This group also proposed a possible larger scale solution that would involve the construction of a solar panel mounting structure over the parking lots. Due to the high expense of building on top of the parking lots, the group only recommended pursuing this if they were able to get 70% government aid. The group also created brochures for employees and for the community to spread information regarding the benefits of solar projects.
3. Methodology
In order to determine the overall feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church, we divided this task into five sections. The first section, site analysis, was concerned with obtaining the physical layout of the roof space suitable for panel placement, as well as determining relevant meteorological data that was needed for energy calculations. The second section, possible solar panels and placements, dealt with determining the criteria and system that would be used to select the best panel style for the church. The third section investigated what the effect of different orientations and configurations of the panels would have on the amount of energy that could be produced. Economic feasibility of the systems, the fourth section, investigated what economic factors and assumptions should be used in order to create an accurate economic model of the solar panel system as an investment vehicle. In the final section, social implications, our objective was to determine what social factors might come into play that could help or hinder the support for the installation of a photovoltaic system.
3.1 Site Analysis
Given the relationship between the sunlight available in a region and a solar cell’s energy output, site analysis was one of the greatest influences on the feasibility of a photovoltaic project. Given the church’s geographical location in Worcester, Massachusetts, several factors were considered. Each factor dealt primarily with the sunlight available or the geographical layout of the designated site. Factors such as location, average sunlight, daily shadows, obtrusive objects, and structural positioning combined to form the project’s site analysis. To obtain the data needed to form our site analysis, the project was divided into a number of domains. The first dealt primarily with the meteorological conditions of Worcester. This domain sought to answer the question of how much sunlight is available, as well gather any information that would ease the calculation of how much energy can potentially be
produced by an array of solar cells. The second domain dealt with the structural layout of the roof space at the Wesley United Methodist Church. This domain was responsible for determining where solar panels could be placed by taking shadows, obtrusive objects, and structural support into consideration. The third domain consisted of gathering and summarizing the current energy usage of the church. This data could be used to form estimates about how much money could be saved through the energy generated by the installation of a solar panel system. The last domain, concerning the installation of solar panels, dealt with determining what factors would come into play when installing the panels onto the roof, as well as integrating the system into the electrical grid.
3.1.1 Meteorological Analysis
Gathering and summarizing meteorological data was a vital aspect for creating the site analysis. Obtaining meteorological data is done with relative ease these days. One of the greatest resources of weather data is provided by GAISMA28. It includes information such as monthly atmospheric clearness as well as sunrise and sunset durations. Most importantly, GAISMA offers a monthly insolation calculation. Insolation is a composite measurement that summarizes the amount of solar radiation that an area receives. The insolation value is a numerical value that represents the average kWh/m2/day in a given month. These values are exceptional tools that encapsulate various meteorological events; for example, this calculation encompasses the change in sunlight due to cloudy or partially cloudy days. The result is a value that describes the amount of solar radiation (sunlight) available in a given area per day. This average was used in the calculation of how much energy would be produced by a given solar panel. This allowed for relatively accurate calculations of future energy production which was essential for determining when a return on investment could be realized.
28 GIASMA [Online] www.giasma.com
3.1.2 Layout of Roof Space
To determine the layout of the roof space, we took preliminary measurements of the roof. With these basic dimensions, we were able to calculate a best-case scenario for mounting solar panels. This best-case scenario acted as an upper bound on the size of the system that could be installed. With the preliminary measurements, we were also able to obtain a set of plans for the roof, with detailed dimensions. From this, a simpler and smaller-sized CAD drawing was created using the set of plans and the measurements taken on the roof. However, the primary problem with taking our measurements at only one time of day was that they didn’t include all possible shadowed areas. Another problem encountered was that we didn’t initially record the locations of any other possible shadows, such as trees or the chimney, which could cast a shadow over several panels at different times of day. Our research on different panels showed that panels should not be partially shaded. It was therefore decided that we would visit the site at different times of day to take detailed measurements of where shadows fell. This allowed us to create a printed plan of the roof space, including areas representing the shaded portions of the roof, using a software modeling program. With this information, a more accurate calculation of the possible area suitable for a photovoltaic system was made. We also determined the necessary spacing of an array using different panels, to figure out how many panels could effectively fit onto the roof’s surface. Inter-panel spacing was important because tilting the panels for the optimum angle of the sun could potentially cause them to cast shadows onto each other. Using trigonometric calculations, we found the spacing necessary between panels to avoid these types of shadows, as well as determined the maximum number of panels as a result of this spacing. This maximum number of panels allowed us to determine how much power could be harnessed in each of our panel configurations.
3.1.3 Energy Usage
We found it necessary to gather previous energy data from the church in order to gain a better understanding of how a solar panel system would affect the overall amount of energy that the church could save. Previous electric bills contained the number of kilowatt hours consumed by the church, as well as the price paid for these hours. Using this data, we were able to summarize the trends in energy usage over the course of the year, and more importantly, compare this energy data to the estimated energy that could be produced by a solar panel installation. The electrical purchasing history of the church also gave us an initial cost of electricity, which was very useful in our economic analysis.
3.1.4 The Installation Process
Researching the installation process was another important aspect of the site analysis. This involved contacting local installers and analyzing the Worcester Code Enforcement to better understand the electric codes relevant to the installation of a photovoltaic system. In addition to this, we contacted National Grid, the power supplier for the church, to find any other regulations pertaining to connecting the church’s solar panel system to the electrical grid. It was also important to determine the nature of the materials that the roof was composed of, and what methods of mounting the panels would work best on these surfaces. Research was done to create a contact list of local installers who would be able to install a system if it were found to be feasible.
3.2 Analysis of Solar Panels and Systems
In our pursuit of the most economical solar panel solution for Wesley United Methodist Church, we came across many possible options for panels, inverters, and other equipment, each with their own costs and benefits. In order to determine which solution was optimal, we enumerated a list of criteria that was used to evaluate each solution.
We decided that the best metric for evaluating a solar system was the cost per Watt produced by the panel. Naturally, the lower this number, the greater energy production that can be purchased for the same dollar amount. This criterion will lead to a better return on investment and fewer years until the church recovers their initial capital. We determined that the second most important criterion for determining the feasibility of a solar panel system was its durability. Less durable systems would incur higher maintenance costs and exhibit a shorter lifetime of operation. The longer the solar system lasts the more energy the church will be able to obtain from it. We decided that the efficiency rating of the photovoltaic panel was important because it is directly related to the maximum power a system using the panel could produce. The church had a set amount of space available for a solar installation. The higher the efficiency of the solar system, the higher the amount of power we could get from a system covering the same amount of space. The availability of a certain solar technology also factored into our analysis of feasibility. There are long waiting lists for some of the newer solar panel technologies, such as thin film solar panels. For this criterion, there was a trade-off between only looking at what is readily available and waiting for a better technology to become available. The weight of the solar panel system was important. The roof at Wesley United Methodist Church is able to support 35lb per square foot, so any system heavier than that was disregarded.
Regulations on a Solar Power System
Figure 6: String Ribbon Manufacturing Process12
http://docs.google.com/File?id=dfd49hhc_5hsjq9mgk_b12 Evergreen Solar, Inc. (2008). String Ribbon. Retrieved October, 2008, from http://evergreensolar.com/images/techology/stringribbon/diagram_string_ribbon_en.jpg
13 Evergreen Solar, Inc. (2008). Our String Ribbon Wafers - Genius in its Simplicity. Retrieved October, 2008, from http://www.evergreensolar.com/app/en/technology/item/48
The result of this process is a thin, silicon ribbon, which is twice the yield of the conventional construction per pound of silicon. Due to this fact, String Ribbon panels use significantly less material than crystalline panels. The process of creating String Ribbon panels achieves a much greater reliability and potency than its silicon wafer counterpart and manufacturing it is one of the most environmentally friendly methods in the business.13
Thin-film Panels
With advent of micro-manufacturing, many large scale photovoltaic panels are becoming smaller and smaller with each progressive decade. The ability to spread a material over a large scale area that averages 1 to 10 micrometers thick has enabled several manufactures to produce an ultra thin variety of solar panels. This newly emerging technology is aptly named: thin-film technology. Thin-film
technology refers to the act of spreading several consecutive layers of silicon and other material to form a working photovoltaic. Thin-film material is 100 times thinner than traditional solar panels, which range from 100 to 300 micrometers thick, and only contains 1% of the silicon to produce an equivalently sized panel.14 The greatest advantages of thin-film technology are that it is flexible, light weight, and incredibly thin. Unlike silicon wafers and String Ribbon panels, many thin-film panels are created as an amorphous material. Instead of being manufactured in chunks and assembled into a panel like String Ribbon panels and silicon wafer panels, thin-film panels are created by combining consecutive thin layers of material together. The result is a single film that is capable of being distributed in rolls or sheets. 15
http://docs.google.com/File?id=dfd49hhc_13cvnqfmfz_b14 PowerFilm, Inc. (2008). Thin Film. Retrieved October, 2008, from http://www.powerfilmsolar.com/technology/index.html 15 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
Figure 7: Thin-film Composition
Today, many thin-film manufacturers have begun producing what is referred to as monolithic integration. Monolithic integration describes the process of integrating the connection junctions between the silicon substrates, which create paths for the electricity to flow from cell to cell, within the amorphous material. This process is can be referred to as the "All-in-one" technique. Because of the character of thin-film material, manufacturers have been able to integrate these connection junctions with such success that many are capable of tolerating a bullet hole without failing. Some are also capable of performing better than traditional silicon wafer panels under low light or shaded
conditions. Monolithic integration reduces manufacturing costs and increases durability of the overall product.
While thin-film technology receives much praise, it does have several drawbacks. Because of its thin nature, thin-film material generally has a lower efficiency compared to its silicon wafer competitor. In consequence, more area must be dedicated to a thin-film panel to produce the same result as a silicon wafer panel of equal power rating. Another disadvantage of a thin material is that durability begins to suffer over time. Thin film solar panels degrade more quickly than other types of technologies which make them candidates for a more frequent replacement.16
16 U.S. Department of Energy. (2006). Polycrystalline Thin Film. Retrieved October, 2008, from http://www1.eere.energy.gov/solar/tf_polycrystalline.html
2.3 Regulations and Installation
There are several rules and regulations in effect that apply to solar array purchasers. Knowing them can not only protect your well being but also save you money. The Massachusetts Technology Collaborative (MTC) provides a wealth of information about the type of funds and rebates available to those interested in installing solar panel arrays on their business or residence. MTC also provides a list of tasks that must be fulfilled before a solar array may be deemed operational and hazard free.
2.3.1 How Solar Panels are Installed
The installation of most roof based solar arrays is a relatively simple process. The primary method involves attaching bolts to the roof support beams, through the roof surface and building a simple framework on top of these bolts to allow a gap between the panels and the roof surface. This gap permits the panels to be installed on roof surfaces ranging from rubber membranes, standard asphalt
shingles, tiles, and slate, even if the roof is somewhat uneven. The gap also allows for airflow to keep the panels cool. The most common way to install panels on a flat roof, like the Wesley Church’s, is to purchase separate frames that assemble into some sort of “A” frame. The panels can be mounted vertically or horizontally with approximately four panels per frame. This frame is then either bolted through the roof into the rafters below, or weighted down with sandbags or something similar. These mounting frames can either be situated at a fixed angle or one that can be adjusted to two or three pre-set angles and locked with removable pins. The adjustment process can be done with two people and increases the efficiency of the cells, while only slightly complicating the mounting frames. On the church roof, several lines of these frames could be assembled with enough space in between to prevent shading from the row in front. Based on the sun’s effect at various times of the day, different groups would be connected in series and then in parallel to the DC/AC converter. These rows should also be spaced in such a way that the roof is still accessible for regular maintenance. While it is possible for homeowners to install several systems themselves, such as the Schott Sunroof PV system, it is generally recommended that one work with a professional contractor. Not only are contractors experienced in installation procedures, they are also familiar with the available rebates and other incentives. Most importantly, the contractor will coordinate with a licensed electrician to make the connections to the breaker panel and request an electrical inspection from the town to ensure that all procedures are up to code.
2.3.2 Regulations on a Solar Power System
In order to ensure the safety of a solar power system, the system must conform to a number of federal, state, and local regulations. In particular, Commonwealth Solar, an organization that offers rebates to individuals or groups wishing to install a solar panel system, outlines a number of criteria that
a solar panel system must meet in order to receive a rebate. These criteria go beyond simple safety measures to include requirements on the life and overall quality of the system.17 Many of the safety regulations for solar panel installations regard the electrical safety of the system. A system installed in Massachusetts must be installed by a licensed electrician, and conform to all federal, state, and local electric and building codes. Wiring must be properly insulated and weatherproofed. Devices that can be disconnected from the rest of the electrical system for service and inspection must also be installed. Although it is not required, the MTC recommends that surge protectors are installed to protect the system components from any electrical surges.
17 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
18 Commonwealth Solar. Overview. Retrieved September, 2008, from http://www.masstech.org/SOLAR/
2.4 Economics
2.4.1 Incentives Available to System Buyers
Because of the increasing demand for renewable energies, a number of organizations have been created to foster the growth of systems that utilize renewable sources. Both public and private institutions can benefit from the incentives that such organizations provide. When determining the feasibility of a solar power system, it is important to consider the economic incentives that may apply, because they may account for a considerable portion of the system cost.
Commonwealth Solar is an initiative from the Massachusetts Technology Collaborative (MTC) to provide rebates to residential, commercial, industrial, and public facilities. Commonwealth Solar provides rebates on photovoltaic systems on a non-competitive, first-come, first-serve basis. Starting in 2008, the initiative has $68 million available over the next four years.18 The amount of reimbursement that an installation may receive depends on the size of the installation (in kW), whether the components
of the system were manufactured in Massachusetts, and whether the installation is on a public or private building. The rebates are calculated in dollars per DC watt of energy produced by the system.
The base rebate per Watt, based on system size, is shown below:19
19 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
Size of system (kW)
1 to 25 kW
>25 to 100 kW
>100 to 200 kW
>200 to 500 kW
Rebate in dollars per watt
$3.25
$3.00
$2.00
$1.50
Table 1: MTC Rebates
. An additional $0.25 per watt will be added if the components of the system were manufactured in Massachusetts . An additional $1.00 per watt will be added if the system is installed on a public building.
In order to receive a grant from Commonwealth Solar, the system that is to be installed must have a projected efficiency of at least 80% compared to a system under optimal conditions. Commonwealth solar derives these optimal efficiencies from the PVWATTS calculations made by the National Renewable Energy Laboratory. The parameters for optimal installation in Worcester, MA are as follows:
. 77% DC to AC conversion rate . A 42 degree array tilt . A due South orientation of the panels
Applying these parameters to the Worcester area produces a kilowatt per hour price of 11.8 cents with a price of 14.8 cents per kilowatt hour if the system is at 80% for the efficiency of the optimal system. Systems with a projected efficiency less than 80% may still be considered for a rebate, but the amount of the rebate is reduced on a sliding scale with reduced efficiency. Using this scale, systems with efficiencies as low as 65% of optimal may still receive a rebate (70% of the normal rebate with a 65% optimal system). The price per kilowatt hour for a system with 65% of optimal efficiency is 19.7 cents.20 In order to be eligible, the installation must be approved by a Massachusetts licensed electrician. The installation must meet all local, state, and federal building and electrical codes. An Interconnection Agreement must also be filed with the utility company to which the system will interface. The components of the solar system to be installed must have certain minimum warranties in order to qualify, including: http://docs.google.com/File?id=dfd49hhc_5hsjq9mgk_b12 Evergreen Solar, Inc. (2008). String Ribbon. Retrieved October, 2008, from http://evergreensolar.com/images/techology/stringribbon/diagram_string_ribbon_en.jpg
13 Evergreen Solar, Inc. (2008). Our String Ribbon Wafers - Genius in its Simplicity. Retrieved October, 2008, from http://www.evergreensolar.com/app/en/technology/item/48
The result of this process is a thin, silicon ribbon, which is twice the yield of the conventional construction per pound of silicon. Due to this fact, String Ribbon panels use significantly less material than crystalline panels. The process of creating String Ribbon panels achieves a much greater reliability and potency than its silicon wafer counterpart and manufacturing it is one of the most environmentally friendly methods in the business.13
Thin-film Panels
With advent of micro-manufacturing, many large scale photovoltaic panels are becoming smaller and smaller with each progressive decade. The ability to spread a material over a large scale area that averages 1 to 10 micrometers thick has enabled several manufactures to produce an ultra thin variety of solar panels. This newly emerging technology is aptly named: thin-film technology. Thin-film
technology refers to the act of spreading several consecutive layers of silicon and other material to form a working photovoltaic. Thin-film material is 100 times thinner than traditional solar panels, which range from 100 to 300 micrometers thick, and only contains 1% of the silicon to produce an equivalently sized panel.14 The greatest advantages of thin-film technology are that it is flexible, light weight, and incredibly thin. Unlike silicon wafers and String Ribbon panels, many thin-film panels are created as an amorphous material. Instead of being manufactured in chunks and assembled into a panel like String Ribbon panels and silicon wafer panels, thin-film panels are created by combining consecutive thin layers of material together. The result is a single film that is capable of being distributed in rolls or sheets. 15
http://docs.google.com/File?id=dfd49hhc_13cvnqfmfz_b14 PowerFilm, Inc. (2008). Thin Film. Retrieved October, 2008, from http://www.powerfilmsolar.com/technology/index.html 15 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
Figure 7: Thin-film Composition
Today, many thin-film manufacturers have begun producing what is referred to as monolithic integration. Monolithic integration describes the process of integrating the connection junctions between the silicon substrates, which create paths for the electricity to flow from cell to cell, within the amorphous material. This process is can be referred to as the "All-in-one" technique. Because of the character of thin-film material, manufacturers have been able to integrate these connection junctions with such success that many are capable of tolerating a bullet hole without failing. Some are also capable of performing better than traditional silicon wafer panels under low light or shaded
conditions. Monolithic integration reduces manufacturing costs and increases durability of the overall product.
While thin-film technology receives much praise, it does have several drawbacks. Because of its thin nature, thin-film material generally has a lower efficiency compared to its silicon wafer competitor. In consequence, more area must be dedicated to a thin-film panel to produce the same result as a silicon wafer panel of equal power rating. Another disadvantage of a thin material is that durability begins to suffer over time. Thin film solar panels degrade more quickly than other types of technologies which make them candidates for a more frequent replacement.16
16 U.S. Department of Energy. (2006). Polycrystalline Thin Film. Retrieved October, 2008, from http://www1.eere.energy.gov/solar/tf_polycrystalline.html
2.3 Regulations and Installation
There are several rules and regulations in effect that apply to solar array purchasers. Knowing them can not only protect your well being but also save you money. The Massachusetts Technology Collaborative (MTC) provides a wealth of information about the type of funds and rebates available to those interested in installing solar panel arrays on their business or residence. MTC also provides a list of tasks that must be fulfilled before a solar array may be deemed operational and hazard free.
2.3.1 How Solar Panels are Installed
The installation of most roof based solar arrays is a relatively simple process. The primary method involves attaching bolts to the roof support beams, through the roof surface and building a simple framework on top of these bolts to allow a gap between the panels and the roof surface. This gap permits the panels to be installed on roof surfaces ranging from rubber membranes, standard asphalt
shingles, tiles, and slate, even if the roof is somewhat uneven. The gap also allows for airflow to keep the panels cool. The most common way to install panels on a flat roof, like the Wesley Church’s, is to purchase separate frames that assemble into some sort of “A” frame. The panels can be mounted vertically or horizontally with approximately four panels per frame. This frame is then either bolted through the roof into the rafters below, or weighted down with sandbags or something similar. These mounting frames can either be situated at a fixed angle or one that can be adjusted to two or three pre-set angles and locked with removable pins. The adjustment process can be done with two people and increases the efficiency of the cells, while only slightly complicating the mounting frames. On the church roof, several lines of these frames could be assembled with enough space in between to prevent shading from the row in front. Based on the sun’s effect at various times of the day, different groups would be connected in series and then in parallel to the DC/AC converter. These rows should also be spaced in such a way that the roof is still accessible for regular maintenance. While it is possible for homeowners to install several systems themselves, such as the Schott Sunroof PV system, it is generally recommended that one work with a professional contractor. Not only are contractors experienced in installation procedures, they are also familiar with the available rebates and other incentives. Most importantly, the contractor will coordinate with a licensed electrician to make the connections to the breaker panel and request an electrical inspection from the town to ensure that all procedures are up to code.
2.3.2 Regulations on a Solar Power System
In order to ensure the safety of a solar power system, the system must conform to a number of federal, state, and local regulations. In particular, Commonwealth Solar, an organization that offers rebates to individuals or groups wishing to install a solar panel system, outlines a number of criteria that
a solar panel system must meet in order to receive a rebate. These criteria go beyond simple safety measures to include requirements on the life and overall quality of the system.17 Many of the safety regulations for solar panel installations regard the electrical safety of the system. A system installed in Massachusetts must be installed by a licensed electrician, and conform to all federal, state, and local electric and building codes. Wiring must be properly insulated and weatherproofed. Devices that can be disconnected from the rest of the electrical system for service and inspection must also be installed. Although it is not required, the MTC recommends that surge protectors are installed to protect the system components from any electrical surges.
17 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
18 Commonwealth Solar. Overview. Retrieved September, 2008, from http://www.masstech.org/SOLAR/
2.4 Economics
2.4.1 Incentives Available to System Buyers
Because of the increasing demand for renewable energies, a number of organizations have been created to foster the growth of systems that utilize renewable sources. Both public and private institutions can benefit from the incentives that such organizations provide. When determining the feasibility of a solar power system, it is important to consider the economic incentives that may apply, because they may account for a considerable portion of the system cost.
Commonwealth Solar is an initiative from the Massachusetts Technology Collaborative (MTC) to provide rebates to residential, commercial, industrial, and public facilities. Commonwealth Solar provides rebates on photovoltaic systems on a non-competitive, first-come, first-serve basis. Starting in 2008, the initiative has $68 million available over the next four years.18 The amount of reimbursement that an installation may receive depends on the size of the installation (in kW), whether the components
of the system were manufactured in Massachusetts, and whether the installation is on a public or private building. The rebates are calculated in dollars per DC watt of energy produced by the system.
The base rebate per Watt, based on system size, is shown below:19
19 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
Size of system (kW)
1 to 25 kW
>25 to 100 kW
>100 to 200 kW
>200 to 500 kW
Rebate in dollars per watt
$3.25
$3.00
$2.00
$1.50
Table 1: MTC Rebates
. An additional $0.25 per watt will be added if the components of the system were manufactured in Massachusetts . An additional $1.00 per watt will be added if the system is installed on a public building.
In order to receive a grant from Commonwealth Solar, the system that is to be installed must have a projected efficiency of at least 80% compared to a system under optimal conditions. Commonwealth solar derives these optimal efficiencies from the PVWATTS calculations made by the National Renewable Energy Laboratory. The parameters for optimal installation in Worcester, MA are as follows:
. 77% DC to AC conversion rate . A 42 degree array tilt . A due South orientation of the panels
Applying these parameters to the Worcester area produces a kilowatt per hour price of 11.8 cents with a price of 14.8 cents per kilowatt hour if the system is at 80% for the efficiency of the optimal system. Systems with a projected efficiency less than 80% may still be considered for a rebate, but the amount of the rebate is reduced on a sliding scale with reduced efficiency. Using this scale, systems with efficiencies as low as 65% of optimal may still receive a rebate (70% of the normal rebate with a 65% optimal system). The price per kilowatt hour for a system with 65% of optimal efficiency is 19.7 cents.20 In order to be eligible, the installation must be approved by a Massachusetts licensed electrician. The installation must meet all local, state, and federal building and electrical codes. An Interconnection Agreement must also be filed with the utility company to which the system will interface. The components of the solar system to be installed must have certain minimum warranties in order to qualify, including:
http://docs.google.com/File?id=dfd49hhc_5hsjq9mgk_b12 Evergreen Solar, Inc. (2008). String Ribbon. Retrieved October, 2008, from http://evergreensolar.com/images/techology/stringribbon/diagram_string_ribbon_en.jpg
13 Evergreen Solar, Inc. (2008). Our String Ribbon Wafers - Genius in its Simplicity. Retrieved October, 2008, from http://www.evergreensolar.com/app/en/technology/item/48
The result of this process is a thin, silicon ribbon, which is twice the yield of the conventional construction per pound of silicon. Due to this fact, String Ribbon panels use significantly less material than crystalline panels. The process of creating String Ribbon panels achieves a much greater reliability and potency than its silicon wafer counterpart and manufacturing it is one of the most environmentally friendly methods in the business.13
Thin-film Panels
With advent of micro-manufacturing, many large scale photovoltaic panels are becoming smaller and smaller with each progressive decade. The ability to spread a material over a large scale area that averages 1 to 10 micrometers thick has enabled several manufactures to produce an ultra thin variety of solar panels. This newly emerging technology is aptly named: thin-film technology. Thin-film
technology refers to the act of spreading several consecutive layers of silicon and other material to form a working photovoltaic. Thin-film material is 100 times thinner than traditional solar panels, which range from 100 to 300 micrometers thick, and only contains 1% of the silicon to produce an equivalently sized panel.14 The greatest advantages of thin-film technology are that it is flexible, light weight, and incredibly thin. Unlike silicon wafers and String Ribbon panels, many thin-film panels are created as an amorphous material. Instead of being manufactured in chunks and assembled into a panel like String Ribbon panels and silicon wafer panels, thin-film panels are created by combining consecutive thin layers of material together. The result is a single film that is capable of being distributed in rolls or sheets. 15
http://docs.google.com/File?id=dfd49hhc_13cvnqfmfz_b14 PowerFilm, Inc. (2008). Thin Film. Retrieved October, 2008, from http://www.powerfilmsolar.com/technology/index.html 15 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
Figure 7: Thin-film Composition
Today, many thin-film manufacturers have begun producing what is referred to as monolithic integration. Monolithic integration describes the process of integrating the connection junctions between the silicon substrates, which create paths for the electricity to flow from cell to cell, within the amorphous material. This process is can be referred to as the "All-in-one" technique. Because of the character of thin-film material, manufacturers have been able to integrate these connection junctions with such success that many are capable of tolerating a bullet hole without failing. Some are also capable of performing better than traditional silicon wafer panels under low light or shaded
conditions. Monolithic integration reduces manufacturing costs and increases durability of the overall product.
While thin-film technology receives much praise, it does have several drawbacks. Because of its thin nature, thin-film material generally has a lower efficiency compared to its silicon wafer competitor. In consequence, more area must be dedicated to a thin-film panel to produce the same result as a silicon wafer panel of equal power rating. Another disadvantage of a thin material is that durability begins to suffer over time. Thin film solar panels degrade more quickly than other types of technologies which make them candidates for a more frequent replacement.16
16 U.S. Department of Energy. (2006). Polycrystalline Thin Film. Retrieved October, 2008, from http://www1.eere.energy.gov/solar/tf_polycrystalline.html
2.3 Regulations and Installation
There are several rules and regulations in effect that apply to solar array purchasers. Knowing them can not only protect your well being but also save you money. The Massachusetts Technology Collaborative (MTC) provides a wealth of information about the type of funds and rebates available to those interested in installing solar panel arrays on their business or residence. MTC also provides a list of tasks that must be fulfilled before a solar array may be deemed operational and hazard free.
2.3.1 How Solar Panels are Installed
The installation of most roof based solar arrays is a relatively simple process. The primary method involves attaching bolts to the roof support beams, through the roof surface and building a simple framework on top of these bolts to allow a gap between the panels and the roof surface. This gap permits the panels to be installed on roof surfaces ranging from rubber membranes, standard asphalt
shingles, tiles, and slate, even if the roof is somewhat uneven. The gap also allows for airflow to keep the panels cool. The most common way to install panels on a flat roof, like the Wesley Church’s, is to purchase separate frames that assemble into some sort of “A” frame. The panels can be mounted vertically or horizontally with approximately four panels per frame. This frame is then either bolted through the roof into the rafters below, or weighted down with sandbags or something similar. These mounting frames can either be situated at a fixed angle or one that can be adjusted to two or three pre-set angles and locked with removable pins. The adjustment process can be done with two people and increases the efficiency of the cells, while only slightly complicating the mounting frames. On the church roof, several lines of these frames could be assembled with enough space in between to prevent shading from the row in front. Based on the sun’s effect at various times of the day, different groups would be connected in series and then in parallel to the DC/AC converter. These rows should also be spaced in such a way that the roof is still accessible for regular maintenance. While it is possible for homeowners to install several systems themselves, such as the Schott Sunroof PV system, it is generally recommended that one work with a professional contractor. Not only are contractors experienced in installation procedures, they are also familiar with the available rebates and other incentives. Most importantly, the contractor will coordinate with a licensed electrician to make the connections to the breaker panel and request an electrical inspection from the town to ensure that all procedures are up to code.
2.3.2 Regulations on a Solar Power System
In order to ensure the safety of a solar power system, the system must conform to a number of federal, state, and local regulations. In particular, Commonwealth Solar, an organization that offers rebates to individuals or groups wishing to install a solar panel system, outlines a number of criteria that
a solar panel system must meet in order to receive a rebate. These criteria go beyond simple safety measures to include requirements on the life and overall quality of the system.17 Many of the safety regulations for solar panel installations regard the electrical safety of the system. A system installed in Massachusetts must be installed by a licensed electrician, and conform to all federal, state, and local electric and building codes. Wiring must be properly insulated and weatherproofed. Devices that can be disconnected from the rest of the electrical system for service and inspection must also be installed. Although it is not required, the MTC recommends that surge protectors are installed to protect the system components from any electrical surges.
17 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
18 Commonwealth Solar. Overview. Retrieved September, 2008, from http://www.masstech.org/SOLAR/
2.4 Economics
2.4.1 Incentives Available to System Buyers
Because of the increasing demand for renewable energies, a number of organizations have been created to foster the growth of systems that utilize renewable sources. Both public and private institutions can benefit from the incentives that such organizations provide. When determining the feasibility of a solar power system, it is important to consider the economic incentives that may apply, because they may account for a considerable portion of the system cost.
Commonwealth Solar is an initiative from the Massachusetts Technology Collaborative (MTC) to provide rebates to residential, commercial, industrial, and public facilities. Commonwealth Solar provides rebates on photovoltaic systems on a non-competitive, first-come, first-serve basis. Starting in 2008, the initiative has $68 million available over the next four years.18 The amount of reimbursement that an installation may receive depends on the size of the installation (in kW), whether the components
of the system were manufactured in Massachusetts, and whether the installation is on a public or private building. The rebates are calculated in dollars per DC watt of energy produced by the system.
The base rebate per Watt, based on system size, is shown below:19
19 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
Size of system (kW)
1 to 25 kW
>25 to 100 kW
>100 to 200 kW
>200 to 500 kW
Rebate in dollars per watt
$3.25
$3.00
$2.00
$1.50
Table 1: MTC Rebates
. An additional $0.25 per watt will be added if the components of the system were manufactured in Massachusetts . An additional $1.00 per watt will be added if the system is installed on a public building.
In order to receive a grant from Commonwealth Solar, the system that is to be installed must have a projected efficiency of at least 80% compared to a system under optimal conditions. Commonwealth solar derives these optimal efficiencies from the PVWATTS calculations made by the National Renewable Energy Laboratory. The parameters for optimal installation in Worcester, MA are as follows:
. 77% DC to AC conversion rate . A 42 degree array tilt . A due South orientation of the panels
Applying these parameters to the Worcester area produces a kilowatt per hour price of 11.8 cents with a price of 14.8 cents per kilowatt hour if the system is at 80% for the efficiency of the optimal system. Systems with a projected efficiency less than 80% may still be considered for a rebate, but the amount of the rebate is reduced on a sliding scale with reduced efficiency. Using this scale, systems with efficiencies as low as 65% of optimal may still receive a rebate (70% of the normal rebate with a 65% optimal system). The price per kilowatt hour for a system with 65% of optimal efficiency is 19.7 cents.20 In order to be eligible, the installation must be approved by a Massachusetts licensed electrician. The installation must meet all local, state, and federal building and electrical codes. An Interconnection Agreement must also be filed with the utility company to which the system will interface. The components of the solar system to be installed must have certain minimum warranties in order to qualify, including: http://docs.google.com/File?id=dfd49hhc_5hsjq9mgk_b12 Evergreen Solar, Inc. (2008). String Ribbon. Retrieved October, 2008, from http://evergreensolar.com/images/techology/stringribbon/diagram_string_ribbon_en.jpg
13 Evergreen Solar, Inc. (2008). Our String Ribbon Wafers - Genius in its Simplicity. Retrieved October, 2008, from http://www.evergreensolar.com/app/en/technology/item/48
The result of this process is a thin, silicon ribbon, which is twice the yield of the conventional construction per pound of silicon. Due to this fact, String Ribbon panels use significantly less material than crystalline panels. The process of creating String Ribbon panels achieves a much greater reliability and potency than its silicon wafer counterpart and manufacturing it is one of the most environmentally friendly methods in the business.13
Thin-film Panels
With advent of micro-manufacturing, many large scale photovoltaic panels are becoming smaller and smaller with each progressive decade. The ability to spread a material over a large scale area that averages 1 to 10 micrometers thick has enabled several manufactures to produce an ultra thin variety of solar panels. This newly emerging technology is aptly named: thin-film technology. Thin-film
technology refers to the act of spreading several consecutive layers of silicon and other material to form a working photovoltaic. Thin-film material is 100 times thinner than traditional solar panels, which range from 100 to 300 micrometers thick, and only contains 1% of the silicon to produce an equivalently sized panel.14 The greatest advantages of thin-film technology are that it is flexible, light weight, and incredibly thin. Unlike silicon wafers and String Ribbon panels, many thin-film panels are created as an amorphous material. Instead of being manufactured in chunks and assembled into a panel like String Ribbon panels and silicon wafer panels, thin-film panels are created by combining consecutive thin layers of material together. The result is a single film that is capable of being distributed in rolls or sheets. 15
http://docs.google.com/File?id=dfd49hhc_13cvnqfmfz_b14 PowerFilm, Inc. (2008). Thin Film. Retrieved October, 2008, from http://www.powerfilmsolar.com/technology/index.html 15 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
Figure 7: Thin-film Composition
Today, many thin-film manufacturers have begun producing what is referred to as monolithic integration. Monolithic integration describes the process of integrating the connection junctions between the silicon substrates, which create paths for the electricity to flow from cell to cell, within the amorphous material. This process is can be referred to as the "All-in-one" technique. Because of the character of thin-film material, manufacturers have been able to integrate these connection junctions with such success that many are capable of tolerating a bullet hole without failing. Some are also capable of performing better than traditional silicon wafer panels under low light or shaded
conditions. Monolithic integration reduces manufacturing costs and increases durability of the overall product.
While thin-film technology receives much praise, it does have several drawbacks. Because of its thin nature, thin-film material generally has a lower efficiency compared to its silicon wafer competitor. In consequence, more area must be dedicated to a thin-film panel to produce the same result as a silicon wafer panel of equal power rating. Another disadvantage of a thin material is that durability begins to suffer over time. Thin film solar panels degrade more quickly than other types of technologies which make them candidates for a more frequent replacement.16
16 U.S. Department of Energy. (2006). Polycrystalline Thin Film. Retrieved October, 2008, from http://www1.eere.energy.gov/solar/tf_polycrystalline.html
2.3 Regulations and Installation
There are several rules and regulations in effect that apply to solar array purchasers. Knowing them can not only protect your well being but also save you money. The Massachusetts Technology Collaborative (MTC) provides a wealth of information about the type of funds and rebates available to those interested in installing solar panel arrays on their business or residence. MTC also provides a list of tasks that must be fulfilled before a solar array may be deemed operational and hazard free.
2.3.1 How Solar Panels are Installed
The installation of most roof based solar arrays is a relatively simple process. The primary method involves attaching bolts to the roof support beams, through the roof surface and building a simple framework on top of these bolts to allow a gap between the panels and the roof surface. This gap permits the panels to be installed on roof surfaces ranging from rubber membranes, standard asphalt
shingles, tiles, and slate, even if the roof is somewhat uneven. The gap also allows for airflow to keep the panels cool. The most common way to install panels on a flat roof, like the Wesley Church’s, is to purchase separate frames that assemble into some sort of “A” frame. The panels can be mounted vertically or horizontally with approximately four panels per frame. This frame is then either bolted through the roof into the rafters below, or weighted down with sandbags or something similar. These mounting frames can either be situated at a fixed angle or one that can be adjusted to two or three pre-set angles and locked with removable pins. The adjustment process can be done with two people and increases the efficiency of the cells, while only slightly complicating the mounting frames. On the church roof, several lines of these frames could be assembled with enough space in between to prevent shading from the row in front. Based on the sun’s effect at various times of the day, different groups would be connected in series and then in parallel to the DC/AC converter. These rows should also be spaced in such a way that the roof is still accessible for regular maintenance. While it is possible for homeowners to install several systems themselves, such as the Schott Sunroof PV system, it is generally recommended that one work with a professional contractor. Not only are contractors experienced in installation procedures, they are also familiar with the available rebates and other incentives. Most importantly, the contractor will coordinate with a licensed electrician to make the connections to the breaker panel and request an electrical inspection from the town to ensure that all procedures are up to code.
2.3.2 Regulations on a Solar Power System
In order to ensure the safety of a solar power system, the system must conform to a number of federal, state, and local regulations. In particular, Commonwealth Solar, an organization that offers rebates to individuals or groups wishing to install a solar panel system, outlines a number of criteria that
a solar panel system must meet in order to receive a rebate. These criteria go beyond simple safety measures to include requirements on the life and overall quality of the system.17 Many of the safety regulations for solar panel installations regard the electrical safety of the system. A system installed in Massachusetts must be installed by a licensed electrician, and conform to all federal, state, and local electric and building codes. Wiring must be properly insulated and weatherproofed. Devices that can be disconnected from the rest of the electrical system for service and inspection must also be installed. Although it is not required, the MTC recommends that surge protectors are installed to protect the system components from any electrical surges.
17 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
18 Commonwealth Solar. Overview. Retrieved September, 2008, from http://www.masstech.org/SOLAR/
2.4 Economics
2.4.1 Incentives Available to System Buyers
Because of the increasing demand for renewable energies, a number of organizations have been created to foster the growth of systems that utilize renewable sources. Both public and private institutions can benefit from the incentives that such organizations provide. When determining the feasibility of a solar power system, it is important to consider the economic incentives that may apply, because they may account for a considerable portion of the system cost.
Commonwealth Solar is an initiative from the Massachusetts Technology Collaborative (MTC) to provide rebates to residential, commercial, industrial, and public facilities. Commonwealth Solar provides rebates on photovoltaic systems on a non-competitive, first-come, first-serve basis. Starting in 2008, the initiative has $68 million available over the next four years.18 The amount of reimbursement that an installation may receive depends on the size of the installation (in kW), whether the components
of the system were manufactured in Massachusetts, and whether the installation is on a public or private building. The rebates are calculated in dollars per DC watt of energy produced by the system.
The base rebate per Watt, based on system size, is shown below:19
19 Commonwealth Solar. (2008). Solar Photovoltaic Rebates: Program Manual. Retrieved September, 2008, from http://www.masstech.org/SOLAR/Commonwealth%20Solar%20Program%20Handbook_v2_070108.pdf
Size of system (kW)
1 to 25 kW
>25 to 100 kW
>100 to 200 kW
>200 to 500 kW
Rebate in dollars per watt
$3.25
$3.00
$2.00
$1.50
Table 1: MTC Rebates
. An additional $0.25 per watt will be added if the components of the system were manufactured in Massachusetts . An additional $1.00 per watt will be added if the system is installed on a public building.
In order to receive a grant from Commonwealth Solar, the system that is to be installed must have a projected efficiency of at least 80% compared to a system under optimal conditions. Commonwealth solar derives these optimal efficiencies from the PVWATTS calculations made by the National Renewable Energy Laboratory. The parameters for optimal installation in Worcester, MA are as follows:
. 77% DC to AC conversion rate . A 42 degree array tilt . A due South orientation of the panels
Applying these parameters to the Worcester area produces a kilowatt per hour price of 11.8 cents with a price of 14.8 cents per kilowatt hour if the system is at 80% for the efficiency of the optimal system. Systems with a projected efficiency less than 80% may still be considered for a rebate, but the amount of the rebate is reduced on a sliding scale with reduced efficiency. Using this scale, systems with efficiencies as low as 65% of optimal may still receive a rebate (70% of the normal rebate with a 65% optimal system). The price per kilowatt hour for a system with 65% of optimal efficiency is 19.7 cents.20 In order to be eligible, the installation must be approved by a Massachusetts licensed electrician. The installation must meet all local, state, and federal building and electrical codes. An Interconnection Agreement must also be filed with the utility company to which the system will interface. The components of the solar system to be installed must have certain minimum warranties in order to qualify, including:
The only remaining piece of the puzzle is the catalyst that starts this transfer of "free" electrons
Figure 1: P-N Junction6
http://docs.google.com/File?id=dfd49hhc_12ffjw9gcg_b6 REUK. Renewable energy UK. Retrieved October, 2008, from http://www.reuk.co.uk/OtherImages/pnjunction.jpg
7 Aldous, S. How solar cells work. Retrieved October, 2008, from http://www.howstuffworks.com/solar-cell.htm
The only remaining piece of the puzzle is the catalyst that starts this transfer of "free" electrons to the "holes" on the other side. This process is called the photovoltaic effect. The photovoltaic effect describes the interaction between a photon, a particle of light, and specific metal materials. When a photon interacts with a metal material it may be reflected or absorbed. If absorbed, the photon transfers its energy to a local atom, which in turn, lends its energy to an orbiting valence electron. This process causes a free electron which is capable of moving to a "hole" creating an electrical current. The more photons that interact with the material, the more valence electrons are freed and allowed to flow to an electron-hole. Once light is absorbed by the two materials, electricity begins to flow through the connected load. The more light that interacts with the solar cell, the more electricity is generated.7
Figure 2: Solar Panel Construction and Implementation8 On a bright, sunny day, the sun shines with approximately 1 kilowatt of energy per square meter on the Earth's surface. To gather this energy solar panels are generally coated with a non-reflective surface texture. This texture increases the probability that a photon will be absorbed rather than reflected. A cross section of composition can be seen below.
http://docs.google.com/File?id=dfd49hhc_11hn4x2ddc_b8 The Seitch Blog. Retrieved October, 2008, from www.blog.thesietch.org/wp-content/uploads/2007/06/solarcell.jpg
Figure 3: Solar Cell Composition
2.2.3 Different Types of Photovoltaic Panels
Crystalline Silicon (Traditional Method)
The largest and most popular solar panel technology on the market today is commonly referred to as crystalline silicon solar cells. Being one of the original solar panel technologies it is not surprising that this type of solar panel currently holds an unprecedented 93% of the market to date. Because of its relatively simple construction and manufacturing process, crystalline solar cells gained large popularity during the infancy of the alternative energy boom.
Today, there are two major types of crystalline silicon used in manufacturing and production: mono-crystalline and poly-crystalline. The first, mono-crystalline, requires absolutely pure semi-conduction material. Melted silicon is first poured in the shape of rods. After a solid has formed, the rods are then sawed into thin small wafers which are up to 150 mm in diameter and 350 microns thick. This type of production results in an approximately 24% lab efficiency, and 15% efficiency in production.9
Solar Panel Layers.bmp9 The Solarserver. (2008). Photovoltaics. Retrieved October, 2008, from http://www.solarserver.de/wissen/photovoltaik-e.html
Figure 4: Mono-Crystalline Solar Cells
The second type of crystalline silicon chiefly used today is referred to as poly-crystalline. Poly-crystalline production is similar to mono-crystalline in the way that both result in silicon wafers, however, the method by which the final product is created differs. First, liquid silicon is poured into blocks that are then cut into bars, and then finally cut into wafers. Because the silicon hardens in large blocks, many large crystalline structures begin to form, hence “poly-crystalline”. Poly-crystalline cells are more cost effective to produce due to the fact that many cells can be created from a single block, but because every time silicon is cut, the edges become deformed, which results in a lower operating efficiency. The efficiency for a poly-crystalline cell in the laboratory is approximately 18% and in production reaches only 14%.10
10 The Solarserver. (2008). Photovoltaics. Retrieved October, 2008, from http://www.solarserver.de/wissen/photovoltaik-e.html
Figure 5: Poly-Crystalline Solar Cells
The benefits of a crystalline solar cell come from the fact that the cells that comprise the overall solar panel are very cheap to produce. Because crystalline cells were one of the first technologies on the scene, much of the production and manufacturing techniques have been refined to their maximum potential. Despite effective production processes, one of the largest problems that plague crystalline silicon cells is the limits of their efficiency. When any crystalline structure is split it undergoes deformation. The technique by which mono-crystalline and poly-crystalline cells are created intensely relies on severing of silicon into smaller pieces. This leaves much of the area deformed which decreases operating efficiency for that cell. This is one of the reasons that String Ribbon technology (which is covered in the next section) is so efficient, because it manufactures silicon in a method that produces no deformities.
String Ribbon Panels
With the ever increasing demand of cheap solar panel production techniques, it has become critical for companies to devise new alternatives for producing silicon. One of the most promising of these techniques is String Ribbon manufacturing. Unlike the generic silicon wafers used in the bulk of solar panel production today, string ribbon provides a healthy alternative which decreases production costs as well as the carbon footprint used to produce a solar cell. The technique behind String Ribbon silicon is the manipulation of surface tension. Two parallel strings are pulled vertically through a silicon melt. As the strings rise, silicon begins to span the distance between the two strings, much like a bubble spans the ring on which it is blown. As the silicon rises it begins to cool and form a hardened structure between the strings. This process continues uninterrupted until the silicon ribbon is of desired length.11
11 SolarHome.org. (2008). String-Ribbon. Retrieved October, 2008, from http://www.solarhome.org/string-ribbon.html
http://docs.google.com/File?id=dfd49hhc_12ffjw9gcg_b6 REUK. Renewable energy UK. Retrieved October, 2008, from http://www.reuk.co.uk/OtherImages/pnjunction.jpg
7 Aldous, S. How solar cells work. Retrieved October, 2008, from http://www.howstuffworks.com/solar-cell.htm
The only remaining piece of the puzzle is the catalyst that starts this transfer of "free" electrons to the "holes" on the other side. This process is called the photovoltaic effect. The photovoltaic effect describes the interaction between a photon, a particle of light, and specific metal materials. When a photon interacts with a metal material it may be reflected or absorbed. If absorbed, the photon transfers its energy to a local atom, which in turn, lends its energy to an orbiting valence electron. This process causes a free electron which is capable of moving to a "hole" creating an electrical current. The more photons that interact with the material, the more valence electrons are freed and allowed to flow to an electron-hole. Once light is absorbed by the two materials, electricity begins to flow through the connected load. The more light that interacts with the solar cell, the more electricity is generated.7
Figure 2: Solar Panel Construction and Implementation8 On a bright, sunny day, the sun shines with approximately 1 kilowatt of energy per square meter on the Earth's surface. To gather this energy solar panels are generally coated with a non-reflective surface texture. This texture increases the probability that a photon will be absorbed rather than reflected. A cross section of composition can be seen below.
http://docs.google.com/File?id=dfd49hhc_11hn4x2ddc_b8 The Seitch Blog. Retrieved October, 2008, from www.blog.thesietch.org/wp-content/uploads/2007/06/solarcell.jpg
Figure 3: Solar Cell Composition
2.2.3 Different Types of Photovoltaic Panels
Crystalline Silicon (Traditional Method)
The largest and most popular solar panel technology on the market today is commonly referred to as crystalline silicon solar cells. Being one of the original solar panel technologies it is not surprising that this type of solar panel currently holds an unprecedented 93% of the market to date. Because of its relatively simple construction and manufacturing process, crystalline solar cells gained large popularity during the infancy of the alternative energy boom.
Today, there are two major types of crystalline silicon used in manufacturing and production: mono-crystalline and poly-crystalline. The first, mono-crystalline, requires absolutely pure semi-conduction material. Melted silicon is first poured in the shape of rods. After a solid has formed, the rods are then sawed into thin small wafers which are up to 150 mm in diameter and 350 microns thick. This type of production results in an approximately 24% lab efficiency, and 15% efficiency in production.9
Solar Panel Layers.bmp9 The Solarserver. (2008). Photovoltaics. Retrieved October, 2008, from http://www.solarserver.de/wissen/photovoltaik-e.html
Figure 4: Mono-Crystalline Solar Cells
The second type of crystalline silicon chiefly used today is referred to as poly-crystalline. Poly-crystalline production is similar to mono-crystalline in the way that both result in silicon wafers, however, the method by which the final product is created differs. First, liquid silicon is poured into blocks that are then cut into bars, and then finally cut into wafers. Because the silicon hardens in large blocks, many large crystalline structures begin to form, hence “poly-crystalline”. Poly-crystalline cells are more cost effective to produce due to the fact that many cells can be created from a single block, but because every time silicon is cut, the edges become deformed, which results in a lower operating efficiency. The efficiency for a poly-crystalline cell in the laboratory is approximately 18% and in production reaches only 14%.10
10 The Solarserver. (2008). Photovoltaics. Retrieved October, 2008, from http://www.solarserver.de/wissen/photovoltaik-e.html
Figure 5: Poly-Crystalline Solar Cells
The benefits of a crystalline solar cell come from the fact that the cells that comprise the overall solar panel are very cheap to produce. Because crystalline cells were one of the first technologies on the scene, much of the production and manufacturing techniques have been refined to their maximum potential. Despite effective production processes, one of the largest problems that plague crystalline silicon cells is the limits of their efficiency. When any crystalline structure is split it undergoes deformation. The technique by which mono-crystalline and poly-crystalline cells are created intensely relies on severing of silicon into smaller pieces. This leaves much of the area deformed which decreases operating efficiency for that cell. This is one of the reasons that String Ribbon technology (which is covered in the next section) is so efficient, because it manufactures silicon in a method that produces no deformities.
String Ribbon Panels
With the ever increasing demand of cheap solar panel production techniques, it has become critical for companies to devise new alternatives for producing silicon. One of the most promising of these techniques is String Ribbon manufacturing. Unlike the generic silicon wafers used in the bulk of solar panel production today, string ribbon provides a healthy alternative which decreases production costs as well as the carbon footprint used to produce a solar cell. The technique behind String Ribbon silicon is the manipulation of surface tension. Two parallel strings are pulled vertically through a silicon melt. As the strings rise, silicon begins to span the distance between the two strings, much like a bubble spans the ring on which it is blown. As the silicon rises it begins to cool and form a hardened structure between the strings. This process continues uninterrupted until the silicon ribbon is of desired length.11
11 SolarHome.org. (2008). String-Ribbon. Retrieved October, 2008, from http://www.solarhome.org/string-ribbon.html
Because the church does not want to incur any debt in order to finance an installation, instead
Because the church does not want to incur any debt in order to finance an installation, instead preferring to use money from gifts or a trust fund, we performed our calculations with a 100% down payment. By analyzing the historical values of the Consumer Price Index we felt that an inflation rate of 3.29% was a good long term estimation, especially considering the estimated 25 year lifespan of a photovoltaic system. The Energy Information Administration predicts that the cost of energy will increase at a rate of 0.6% over inflation. Evaluating various sized installations using the information above yielded similar economic results across system sizes. Without the additional income provided by renewable energy credits, the investment turns positive after 22 years. With renewable energy credit income, this figure drops to 19 years. The investment potential of a photovoltaic system was found to be largely tied to the overall cost per watt figure cited by installers. If this figure were to drop, the nature of the investment could change significantly. For example, if the overall price per watt were to drop to $6.50, even without renewable energy credit income, the investment would become economical in 15 years. The cost of electricity and how fast this cost is expected to rise also impacts the investment. For each additional 0.6% of estimated increase in electricity, one year is deducted from the investment breakeven point. Our recommendation to the church was to delay the purchase of a photovoltaic system. Although the investment would become economical after a period of time shorter than the lifespan of the system, its economic benefit would not be substantial. In addition to this, the costs of photovoltaic panels are expected to drop significantly in the near future, causing an investment taken in a few years to be substantially more beneficial.
Table of Contents
Abstract ........................................................................................................................................................ 3 Executive Summary ...................................................................................................................................... 4 Table of Contents ......................................................................................................................................... 8 Table of Figures .......................................................................................................................................... 11 Table of Tables ........................................................................................................................................... 11 1. Introduction ........................................................................................................................................... 12 2. Background ............................................................................................................................................ 14 2.1 History of the Church ........................................................................................................................ 14 2.2 Solar Technology ............................................................................................................................... 15 2.2.1 The History of Solar Power ........................................................................................................ 15 2.2.2 How Solar Power Works ............................................................................................................ 16 2.2.3 Different Types of Photovoltaic Panels ...................................................................................... 20 2.3 Regulations and Installation .............................................................................................................. 25 2.3.1 How Solar Panels are Installed ................................................................................................... 25 2.3.2 Regulations on a Solar Power System ........................................................................................ 26 2.4 Economics ........................................................................................................................................ 27 2.4.1 Incentives Available to System Buyers ...................................................................................... 27 2.4.2 Factors in Determining Economic Feasibility ............................................................................. 31 2.5 Similar Case Studies .......................................................................................................................... 33 2.5.1 Holy Name Wind Power Feasibility Study .................................................................................. 33 2.5.2 Solar Feasibility Study of a Learning Center at WPI ................................................................... 34 2.5.3 Janssen Ortho LLC Solar Power Feasibility Study ....................................................................... 35 3. Methodology .......................................................................................................................................... 37 3.1 Site Analysis ..................................................................................................................................... 37 3.1.1 Meteorological Analysis ............................................................................................................. 38 3.1.2 Layout of Roof Space ................................................................................................................. 39 3.1.3 Energy Usage ............................................................................................................................. 40 3.1.4 The Installation Process ............................................................................................................. 40 3.2 Analysis of Solar Panels and Systems ................................................................................................ 40 3.3 Solar Panel Placement ...................................................................................................................... 43 3.4 Economic Feasibility of the Systems ................................................................................................. 46 3.5 Social Implications ............................................................................................................................. 49 4. Site Analysis ........................................................................................................................................... 52 4.1 Location of the Church ...................................................................................................................... 52 4.2 Meteorological Analysis .................................................................................................................... 52 4.3 Layout of Roof Space ........................................................................................................................ 56 4.4 Energy Usage .................................................................................................................................... 58 4.5 The Installation Process .................................................................................................................... 60 5. Possible Solar Panels and Inverters ........................................................................................................ 63 5.1 Solar panels ...................................................................................................................................... 63 5.2 Inverter Choice ................................................................................................................................. 65 6. Economic Context .................................................................................................................................. 67 7. Scenarios ................................................................................................................................................ 75 7.1 Assumptions and Selection of Solar Panels ...................................................................................... 75 7.2 Scenario 1: Small System Size: .......................................................................................................... 76 Characteristics: .................................................................................................................................. 77 Impact: ............................................................................................................................................... 77 7. 3 Scenario 2: Moderate System Size: .................................................................................................. 78 Characteristics: .................................................................................................................................. 78 Impact: ............................................................................................................................................... 79 7.4 Scenario 3: Maximum System Size: .................................................................................................. 80 Characteristics: .................................................................................................................................. 80 Impact: ............................................................................................................................................... 81 7.5 Scenario 4: Maximum System Size with Volunteer installation: ...................................................... 82 Characteristics: .................................................................................................................................. 82 Impact: ............................................................................................................................................... 83 7.6 Assessment: ..................................................................................................................................... 84 7.7 Sensitivity Analysis ............................................................................................................................ 85 8. Social and Environmental Impact ........................................................................................................... 88 8.1 Effects on Carbon Footprint .............................................................................................................. 88 8.2 Environmental Stewardship .............................................................................................................. 89 8.3 Informational Brochure ..................................................................................................................... 90 8.4 Survey ............................................................................................................................................... 90 9. Conclusions and Recommendations ....................................................................................................... 93 Appendix A: Solar Panel Tilt Analysis ...................................................................................................... 95 Appendix B: Recommended Bidding Process ......................................................................................... 98 Appendix C: Site Dimensions ................................................................................................................ 100 Appendix D: Morning Shade ................................................................................................................. 101 Appendix E: Afternoon Shade ............................................................................................................... 102 Appendix F: Shading with Raised Panels ............................................................................................... 103 Appendix G: Meetings and Correspondences ...................................................................................... 104 Meeting with Tom Sikina on December 5, 2008: ............................................................................. 104 Meeting with York-Ogunquit United Methodist Church .................................................................. 106 Correspondences with the Massachusetts Technology Collaborative: ............................................ 107 Correspondences with solar panel installers: ................................................................................... 107 Appendix H: Solar panel installers ........................................................................................................ 109 Appendix I: Future Solar Panel Costs .................................................................................................... 110 Appendix J: Scale Model ....................................................................................................................... 112 Appendix K: Site Pictures ...................................................................................................................... 115 Appendix L: Simplified Economic Spreadsheet ..................................................................................... 118 Appendix M: Informational Brochure ................................................................................................... 120 Appendix N: Survey ............................................................................................................................... 123 Works Cited .............................................................................................................................................. 124
Table of Figures
Figure 1: P-N Junction ................................................................................................................................ 18 Figure 2: Solar Panel Construction and Implementation ............................................................................ 19 Figure 3: Solar Cell Composition ................................................................................................................. 20 Figure 4: Mono-Crystalline Solar Cells ........................................................................................................ 21 Figure 5: Poly-Crystalline Solar Cells ........................................................................................................... 21 Figure 6: String Ribbon Manufacturing Process.......................................................................................... 23 Figure 7: Thin-film Composition.................................................................................................................. 24 Figure 8: Depiction of the Sun Rays vs the Tilt of the Solar Panels............................................................. 44 Figure 9: Mean Daily Irradiation for Worcester .......................................................................................... 55 Figure 10: Weasly United Methodist Church’s Electricity Consumption .................................................... 59 Figure 11: Power Consumption vs Energy Production of a 20 kW System ................................................. 60 Figure 12: A screenshot of the economics spreadsheet. ............................................................................ 68 Figure 13: Solar panel efficiency over time................................................................................................. 70 Figure 14: Historical prices of the national average cost per kWh. ............................................................ 71 Figure 15: The year to year percent change in the Consumer Price Index. ................................................ 73 Figure 16: The amount of money required to have the same value as $10 in 1914. ................................. 74 Figure 17: 10kW System Energy Production ............................................................................................... 77 Figure 18: 10kW System Cash Flow ............................................................................................................ 78 Figure 19: 15kW System Energy Production ............................................................................................... 79 Figure 20: 15kW System Cash Flow ............................................................................................................ 80 Figure 21: 25kW System Energy Production ............................................................................................... 81 Figure 22: 25kW System Cash Flow ............................................................................................................ 82 Figure 23: 25kW System Energy Production ............................................................................................... 83 Figure 24: 25kW System Cash Flow with Volunteer Installation ................................................................ 84 Figure 25: Futuristic 25kW System Cash Flow ............................................................................................ 86 Figure 26: The Effect of Waiting 5 Years ..................................................................................................... 87 Figure 27: Graph showing the falling cost of PV intallations in Japan. ..................................................... 111 Table of Tables
Table 1: MTC Rebates ................................................................................................................................ 28 Table 2: Solar Panel Criteria ........................................................................................................................ 42 Table 3: Potential Solar Panels .................................................................................................................... 64 Table 4: Potential Inverters ......................................................................................................................... 66
Table of Contents
Abstract ........................................................................................................................................................ 3 Executive Summary ...................................................................................................................................... 4 Table of Contents ......................................................................................................................................... 8 Table of Figures .......................................................................................................................................... 11 Table of Tables ........................................................................................................................................... 11 1. Introduction ........................................................................................................................................... 12 2. Background ............................................................................................................................................ 14 2.1 History of the Church ........................................................................................................................ 14 2.2 Solar Technology ............................................................................................................................... 15 2.2.1 The History of Solar Power ........................................................................................................ 15 2.2.2 How Solar Power Works ............................................................................................................ 16 2.2.3 Different Types of Photovoltaic Panels ...................................................................................... 20 2.3 Regulations and Installation .............................................................................................................. 25 2.3.1 How Solar Panels are Installed ................................................................................................... 25 2.3.2 Regulations on a Solar Power System ........................................................................................ 26 2.4 Economics ........................................................................................................................................ 27 2.4.1 Incentives Available to System Buyers ...................................................................................... 27 2.4.2 Factors in Determining Economic Feasibility ............................................................................. 31 2.5 Similar Case Studies .......................................................................................................................... 33 2.5.1 Holy Name Wind Power Feasibility Study .................................................................................. 33 2.5.2 Solar Feasibility Study of a Learning Center at WPI ................................................................... 34 2.5.3 Janssen Ortho LLC Solar Power Feasibility Study ....................................................................... 35 3. Methodology .......................................................................................................................................... 37 3.1 Site Analysis ..................................................................................................................................... 37 3.1.1 Meteorological Analysis ............................................................................................................. 38 3.1.2 Layout of Roof Space ................................................................................................................. 39 3.1.3 Energy Usage ............................................................................................................................. 40 3.1.4 The Installation Process ............................................................................................................. 40 3.2 Analysis of Solar Panels and Systems ................................................................................................ 40 3.3 Solar Panel Placement ...................................................................................................................... 43 3.4 Economic Feasibility of the Systems ................................................................................................. 46 3.5 Social Implications ............................................................................................................................. 49 4. Site Analysis ........................................................................................................................................... 52 4.1 Location of the Church ...................................................................................................................... 52 4.2 Meteorological Analysis .................................................................................................................... 52 4.3 Layout of Roof Space ........................................................................................................................ 56 4.4 Energy Usage .................................................................................................................................... 58 4.5 The Installation Process .................................................................................................................... 60 5. Possible Solar Panels and Inverters ........................................................................................................ 63 5.1 Solar panels ...................................................................................................................................... 63 5.2 Inverter Choice ................................................................................................................................. 65 6. Economic Context .................................................................................................................................. 67 7. Scenarios ................................................................................................................................................ 75 7.1 Assumptions and Selection of Solar Panels ...................................................................................... 75 7.2 Scenario 1: Small System Size: .......................................................................................................... 76 Characteristics: .................................................................................................................................. 77 Impact: ............................................................................................................................................... 77 7. 3 Scenario 2: Moderate System Size: .................................................................................................. 78 Characteristics: .................................................................................................................................. 78 Impact: ............................................................................................................................................... 79 7.4 Scenario 3: Maximum System Size: .................................................................................................. 80 Characteristics: .................................................................................................................................. 80 Impact: ............................................................................................................................................... 81 7.5 Scenario 4: Maximum System Size with Volunteer installation: ...................................................... 82 Characteristics: .................................................................................................................................. 82 Impact: ............................................................................................................................................... 83 7.6 Assessment: ..................................................................................................................................... 84 7.7 Sensitivity Analysis ............................................................................................................................ 85 8. Social and Environmental Impact ........................................................................................................... 88 8.1 Effects on Carbon Footprint .............................................................................................................. 88 8.2 Environmental Stewardship .............................................................................................................. 89 8.3 Informational Brochure ..................................................................................................................... 90 8.4 Survey ............................................................................................................................................... 90 9. Conclusions and Recommendations ....................................................................................................... 93 Appendix A: Solar Panel Tilt Analysis ...................................................................................................... 95 Appendix B: Recommended Bidding Process ......................................................................................... 98 Appendix C: Site Dimensions ................................................................................................................ 100 Appendix D: Morning Shade ................................................................................................................. 101 Appendix E: Afternoon Shade ............................................................................................................... 102 Appendix F: Shading with Raised Panels ............................................................................................... 103 Appendix G: Meetings and Correspondences ...................................................................................... 104 Meeting with Tom Sikina on December 5, 2008: ............................................................................. 104 Meeting with York-Ogunquit United Methodist Church .................................................................. 106 Correspondences with the Massachusetts Technology Collaborative: ............................................ 107 Correspondences with solar panel installers: ................................................................................... 107 Appendix H: Solar panel installers ........................................................................................................ 109 Appendix I: Future Solar Panel Costs .................................................................................................... 110 Appendix J: Scale Model ....................................................................................................................... 112 Appendix K: Site Pictures ...................................................................................................................... 115 Appendix L: Simplified Economic Spreadsheet ..................................................................................... 118 Appendix M: Informational Brochure ................................................................................................... 120 Appendix N: Survey ............................................................................................................................... 123 Works Cited .............................................................................................................................................. 124
Table of Figures
Figure 1: P-N Junction ................................................................................................................................ 18 Figure 2: Solar Panel Construction and Implementation ............................................................................ 19 Figure 3: Solar Cell Composition ................................................................................................................. 20 Figure 4: Mono-Crystalline Solar Cells ........................................................................................................ 21 Figure 5: Poly-Crystalline Solar Cells ........................................................................................................... 21 Figure 6: String Ribbon Manufacturing Process.......................................................................................... 23 Figure 7: Thin-film Composition.................................................................................................................. 24 Figure 8: Depiction of the Sun Rays vs the Tilt of the Solar Panels............................................................. 44 Figure 9: Mean Daily Irradiation for Worcester .......................................................................................... 55 Figure 10: Weasly United Methodist Church’s Electricity Consumption .................................................... 59 Figure 11: Power Consumption vs Energy Production of a 20 kW System ................................................. 60 Figure 12: A screenshot of the economics spreadsheet. ............................................................................ 68 Figure 13: Solar panel efficiency over time................................................................................................. 70 Figure 14: Historical prices of the national average cost per kWh. ............................................................ 71 Figure 15: The year to year percent change in the Consumer Price Index. ................................................ 73 Figure 16: The amount of money required to have the same value as $10 in 1914. ................................. 74 Figure 17: 10kW System Energy Production ............................................................................................... 77 Figure 18: 10kW System Cash Flow ............................................................................................................ 78 Figure 19: 15kW System Energy Production ............................................................................................... 79 Figure 20: 15kW System Cash Flow ............................................................................................................ 80 Figure 21: 25kW System Energy Production ............................................................................................... 81 Figure 22: 25kW System Cash Flow ............................................................................................................ 82 Figure 23: 25kW System Energy Production ............................................................................................... 83 Figure 24: 25kW System Cash Flow with Volunteer Installation ................................................................ 84 Figure 25: Futuristic 25kW System Cash Flow ............................................................................................ 86 Figure 26: The Effect of Waiting 5 Years ..................................................................................................... 87 Figure 27: Graph showing the falling cost of PV intallations in Japan. ..................................................... 111 Table of Tables
Table 1: MTC Rebates ................................................................................................................................ 28 Table 2: Solar Panel Criteria ........................................................................................................................ 42 Table 3: Potential Solar Panels .................................................................................................................... 64 Table 4: Potential Inverters ......................................................................................................................... 66
The need for energy from renewable sources has become a pressing issue in recent years. Many
1. Introduction
The need for energy from renewable sources has become a pressing issue in recent years. Many individuals and organizations have become concerned about the future energy needs of our society and have begun searching for ways to meet these needs. With the finite and rapidly depleting reserves of oil, coal, and natural gas, it has become a chief issue to discover sources of renewable energy and implement systems that harness them. An energy infrastructure based on renewable sources would be better able to sustain the needs of a society with continually increasing energy demands due to its growth in size and its increased standard of living. The adoption of such systems would also have a positive impact on our environment. Renewable forms of energy, such as solar, wind, or geothermal power produce virtually no pollution. The implementation of renewable energy systems may even be a wise investment; energy produced by such systems would no longer have to be purchased, and over a period of time, these savings in energy costs may exceed the price of the system. The Wesley United Methodist Church, located in Worcester, Massachusetts, is interested in the feasibility of implementing such a system. The church incurs a costly electric bill, which, coupled with a gas heating bill, imposes a significant financial burden. Concerned that the costs of electricity would only rise in the future, the church’s business administrator began looking into alternative energy options. The church has a prominent, south-facing roof space, and its leadership is particularly interested in determining if a solar power system could be installed to utilize this space.
The goal of this project was to determine the economic feasibility of installing a solar power system on the roof of the Wesley United Methodist Church. New incentives and agencies, such as Commonwealth Solar, are making it more affordable to install renewable energy systems. Also, as the demand grows for renewable energy, more cost effective technologies and production processes are being developed to meet the growing demand. It is the infancy and volatility of this market that warrants an up to date investigation of the current options and their costs.
The feasibility of installing a solar array on the Wesley United Methodist Church was determined by gathering pertinent weather data, conducting a site analysis, investigating possible solar panels and mounting solutions, and finally, creating an economic model. These attributes combined to form a final solution through which we determined the investment potential as well as the social and environmental impacts of implementing such a system. Our results indicated that both a system of small size and a larger size would both have a payback period of roughly 19 years.
2. Background
Humans have always been fascinated with the power of the sun. Egyptian pharaohs claimed to be direct descendents of Re, the sun god, and creator of light and all other things. Greek mythology tells the story of Icarus, who flew too close to the sun while using wax wings and plunged to his death. For years, cultures worshipped the sun for the power it gave to life. Many cultures still respect the sun for its central role in sustaining life on earth. Since the 1800s, scientists have made progress towards harnessing the sun’s power in the form of electrical energy. Throughout the last two centuries, significant progress has been made in developing the solar technologies we have today. Many photovoltaic installations are connected to the power grid, and thus each installation is accompanied by many regulations. This chapter provides a broad overview of how photovoltaic panels work, the economics involved in determining the feasibility of a photovoltaic system, and a summary of similar case studies.
2.1 History of the Church
The vision of building Wesley United Methodist Church began in two smaller congregations in 1923. After months of planning, the members of Grace Church (formerly on Walnut Street) and Trinity Church (on Main and Chandler Streets) came together with their pastors (Dr. James Wagner and Dr. Berton Jennings) to join their two churches and establish one Methodist Church in the city of Worcester. The present location was chosen as the future site of this joint effort. It was decided that a new name would be chosen for this new church. Wesley United Methodist Church is named after the founder of Methodism, John Wesley. In addition to a new name, both pastors felt a new minister should be appointed to pastor this newly joined congregation.
According to the official histories of Wesley United Methodist Church, the first construction loan of $350,000 was made possible by the trustees who put themselves and their families on the line,
signing the bank notes personally. The women of the church had taken on the responsibility of paying for the marble altar in the sanctuary. This was done by donations of gold and silver jewelry as well as other items which were sold to make this gift possible. A construction firm from Boston was hired and on May 8, 1927 the first Sunday worship was held in the present building. The first Easter services included 2552 people in two services! The church’s foundational statement is etched in stone over the entrance on 114 Main Street. It reads, “To the glory of God and the service of man.” Wesley Church continues to exist as a place where all may come to worship God and be nourished by God’s love.
2.2 Solar Technology
Solar technology has evolved drastically since humans first became interested in the sun. In the 1800s the photoelectric effect was discovered, and since then, scientific progress has been made towards harnessing the sun’s power. Today, there are many types of solar technology, including crystalline silicon (the traditional method) and newer alternatives such as string ribbon and thin film technologies.
2.2.1 The History of Solar Power
The word “photovoltaic” comes from the Greek word “photo” meaning light and after Count Volta, the Italian physicist (1745-1827) whom the electrical unit Volt is named after. Photovoltaic technology began in 1839 with the French physicist Alexandre Becqueral’s discovery of the photo effect. In 1877 the first photovoltaic cell was constructed from Selenium. The photovoltaic effect was further explained by Albert Einstein and Robert Millikan in the early 1900’s. Finally, in the 1950’s, Shockley
provided a model for the p-n junction, which enabled the beginning of modern photovoltaic technology development.1
1 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
2 Lund, H., Nilson, R., Solamatova, D. & Skare, E. The History Highlight of Solar Cells. Retrieved October, 2008, from http://org.ntnu.no/solarcells/pages/history.php
3 Aldous, S. How Solar Cells Work. Retrieved October, 2008, from http://www.howstuffworks.com/solar-cell.htm
4 Radiochemistry Society. Periodic Table of Elements: Silicon. Retrieved October, 2008, from http://www.radiochemistry.org/periodictable/elements/14.html
In 1954 Bell Labs produced the first modern photovoltaic cell with an efficiency of only four percent.2 Early solar panels carried high price tags, usually costing a couple of thousand dollars per Watt. Energy generated at this cost was only feasible for space projects. Research in this arena progressively drove the costs lower and the efficiencies higher. In the last half century, photovoltaic technology has continued to improve, as has the economics of photovoltaic power generation.
2.2.2 How Solar Power Works
Solar cells, also called photovoltaic cells, are used to convert the electromagnetic radiation from the sun into electricity that can be used to power today’s electronic gadgets, as well as residential and commercial dwellings. The simplest photovoltaic cells are comprised primarily of three materials, silicon, and two doping agents.3 Silicon, which comprises a majority of the photovoltaic cell, has several chemical properties that make it well suited for the use in solar cells. It is the second most abundant element on Earth and has four valence electrons.4 Valence electrons, in layman’s terms, can be thought of as "free" electrons. These "free" electrons are capable of bonding atoms together, as well as doing electro-magnetic work. In pure silicon, atoms bond together via their valence electrons to form a crystalline structure. However, because these valence electrons are tied up bonding atoms together, they cannot be used to produce electricity. This is the primary reason two doping agents are applied to the silicon material. Silicon, on its own, cannot produce electricity. Instead, atoms with greater than or
less than four valence electrons are added to the silicon structure to produce an impurity. Adding this impurity to the silicon structure is what allows the flow of electricity.5 If a Phosphorous doping agent, which has five valence electrons, is added to a group of silicon atoms, it produces a crystalline structure with a "free" valence electron. This "free" valence electron can be used to generate electricity. This type of material is given the name "n-type material". The only thing needed is a place for this "free" electron to flow. No electrical work can be done if there is no potential between two points. The solution to this problem lies within our second doping agent. The second doping agent, unlike the first, has fewer than four valence electrons. As a result, when a structure of Silicon and Boron, an element with only three valence electrons, is formed, "holes" begin to develop within the material structure. These "holes" are the absence of an electron and are capable of being filled by other electrons within the structure. This material is given the name "p-type" material. Now we have two parts to this puzzle. One puzzle piece is Silicon doped with a material that produces "free" electrons. The second is Silicon doped with an element that produces "holes" within the structure that is capable of being filled by "free" electrons. A solar panel is comprised of both n-type material and p-type material. Both materials are sandwiched together to produce what is referred to as a "p-n junction".
5 Cooler Planet. (2008). How Photovoltaic Cells Work. Retrieved October, 2008, from http://solar.coolerplanet.com/Content/Photovoltaic.aspx
The need for energy from renewable sources has become a pressing issue in recent years. Many individuals and organizations have become concerned about the future energy needs of our society and have begun searching for ways to meet these needs. With the finite and rapidly depleting reserves of oil, coal, and natural gas, it has become a chief issue to discover sources of renewable energy and implement systems that harness them. An energy infrastructure based on renewable sources would be better able to sustain the needs of a society with continually increasing energy demands due to its growth in size and its increased standard of living. The adoption of such systems would also have a positive impact on our environment. Renewable forms of energy, such as solar, wind, or geothermal power produce virtually no pollution. The implementation of renewable energy systems may even be a wise investment; energy produced by such systems would no longer have to be purchased, and over a period of time, these savings in energy costs may exceed the price of the system. The Wesley United Methodist Church, located in Worcester, Massachusetts, is interested in the feasibility of implementing such a system. The church incurs a costly electric bill, which, coupled with a gas heating bill, imposes a significant financial burden. Concerned that the costs of electricity would only rise in the future, the church’s business administrator began looking into alternative energy options. The church has a prominent, south-facing roof space, and its leadership is particularly interested in determining if a solar power system could be installed to utilize this space.
The goal of this project was to determine the economic feasibility of installing a solar power system on the roof of the Wesley United Methodist Church. New incentives and agencies, such as Commonwealth Solar, are making it more affordable to install renewable energy systems. Also, as the demand grows for renewable energy, more cost effective technologies and production processes are being developed to meet the growing demand. It is the infancy and volatility of this market that warrants an up to date investigation of the current options and their costs.
The feasibility of installing a solar array on the Wesley United Methodist Church was determined by gathering pertinent weather data, conducting a site analysis, investigating possible solar panels and mounting solutions, and finally, creating an economic model. These attributes combined to form a final solution through which we determined the investment potential as well as the social and environmental impacts of implementing such a system. Our results indicated that both a system of small size and a larger size would both have a payback period of roughly 19 years.
2. Background
Humans have always been fascinated with the power of the sun. Egyptian pharaohs claimed to be direct descendents of Re, the sun god, and creator of light and all other things. Greek mythology tells the story of Icarus, who flew too close to the sun while using wax wings and plunged to his death. For years, cultures worshipped the sun for the power it gave to life. Many cultures still respect the sun for its central role in sustaining life on earth. Since the 1800s, scientists have made progress towards harnessing the sun’s power in the form of electrical energy. Throughout the last two centuries, significant progress has been made in developing the solar technologies we have today. Many photovoltaic installations are connected to the power grid, and thus each installation is accompanied by many regulations. This chapter provides a broad overview of how photovoltaic panels work, the economics involved in determining the feasibility of a photovoltaic system, and a summary of similar case studies.
2.1 History of the Church
The vision of building Wesley United Methodist Church began in two smaller congregations in 1923. After months of planning, the members of Grace Church (formerly on Walnut Street) and Trinity Church (on Main and Chandler Streets) came together with their pastors (Dr. James Wagner and Dr. Berton Jennings) to join their two churches and establish one Methodist Church in the city of Worcester. The present location was chosen as the future site of this joint effort. It was decided that a new name would be chosen for this new church. Wesley United Methodist Church is named after the founder of Methodism, John Wesley. In addition to a new name, both pastors felt a new minister should be appointed to pastor this newly joined congregation.
According to the official histories of Wesley United Methodist Church, the first construction loan of $350,000 was made possible by the trustees who put themselves and their families on the line,
signing the bank notes personally. The women of the church had taken on the responsibility of paying for the marble altar in the sanctuary. This was done by donations of gold and silver jewelry as well as other items which were sold to make this gift possible. A construction firm from Boston was hired and on May 8, 1927 the first Sunday worship was held in the present building. The first Easter services included 2552 people in two services! The church’s foundational statement is etched in stone over the entrance on 114 Main Street. It reads, “To the glory of God and the service of man.” Wesley Church continues to exist as a place where all may come to worship God and be nourished by God’s love.
2.2 Solar Technology
Solar technology has evolved drastically since humans first became interested in the sun. In the 1800s the photoelectric effect was discovered, and since then, scientific progress has been made towards harnessing the sun’s power. Today, there are many types of solar technology, including crystalline silicon (the traditional method) and newer alternatives such as string ribbon and thin film technologies.
2.2.1 The History of Solar Power
The word “photovoltaic” comes from the Greek word “photo” meaning light and after Count Volta, the Italian physicist (1745-1827) whom the electrical unit Volt is named after. Photovoltaic technology began in 1839 with the French physicist Alexandre Becqueral’s discovery of the photo effect. In 1877 the first photovoltaic cell was constructed from Selenium. The photovoltaic effect was further explained by Albert Einstein and Robert Millikan in the early 1900’s. Finally, in the 1950’s, Shockley
provided a model for the p-n junction, which enabled the beginning of modern photovoltaic technology development.1
1 Quaschning, Volkerr. Understanding Renewable Energy Sources. London : Earthscan, 2005.
2 Lund, H., Nilson, R., Solamatova, D. & Skare, E. The History Highlight of Solar Cells. Retrieved October, 2008, from http://org.ntnu.no/solarcells/pages/history.php
3 Aldous, S. How Solar Cells Work. Retrieved October, 2008, from http://www.howstuffworks.com/solar-cell.htm
4 Radiochemistry Society. Periodic Table of Elements: Silicon. Retrieved October, 2008, from http://www.radiochemistry.org/periodictable/elements/14.html
In 1954 Bell Labs produced the first modern photovoltaic cell with an efficiency of only four percent.2 Early solar panels carried high price tags, usually costing a couple of thousand dollars per Watt. Energy generated at this cost was only feasible for space projects. Research in this arena progressively drove the costs lower and the efficiencies higher. In the last half century, photovoltaic technology has continued to improve, as has the economics of photovoltaic power generation.
2.2.2 How Solar Power Works
Solar cells, also called photovoltaic cells, are used to convert the electromagnetic radiation from the sun into electricity that can be used to power today’s electronic gadgets, as well as residential and commercial dwellings. The simplest photovoltaic cells are comprised primarily of three materials, silicon, and two doping agents.3 Silicon, which comprises a majority of the photovoltaic cell, has several chemical properties that make it well suited for the use in solar cells. It is the second most abundant element on Earth and has four valence electrons.4 Valence electrons, in layman’s terms, can be thought of as "free" electrons. These "free" electrons are capable of bonding atoms together, as well as doing electro-magnetic work. In pure silicon, atoms bond together via their valence electrons to form a crystalline structure. However, because these valence electrons are tied up bonding atoms together, they cannot be used to produce electricity. This is the primary reason two doping agents are applied to the silicon material. Silicon, on its own, cannot produce electricity. Instead, atoms with greater than or
less than four valence electrons are added to the silicon structure to produce an impurity. Adding this impurity to the silicon structure is what allows the flow of electricity.5 If a Phosphorous doping agent, which has five valence electrons, is added to a group of silicon atoms, it produces a crystalline structure with a "free" valence electron. This "free" valence electron can be used to generate electricity. This type of material is given the name "n-type material". The only thing needed is a place for this "free" electron to flow. No electrical work can be done if there is no potential between two points. The solution to this problem lies within our second doping agent. The second doping agent, unlike the first, has fewer than four valence electrons. As a result, when a structure of Silicon and Boron, an element with only three valence electrons, is formed, "holes" begin to develop within the material structure. These "holes" are the absence of an electron and are capable of being filled by other electrons within the structure. This material is given the name "p-type" material. Now we have two parts to this puzzle. One puzzle piece is Silicon doped with a material that produces "free" electrons. The second is Silicon doped with an element that produces "holes" within the structure that is capable of being filled by "free" electrons. A solar panel is comprised of both n-type material and p-type material. Both materials are sandwiched together to produce what is referred to as a "p-n junction".
5 Cooler Planet. (2008). How Photovoltaic Cells Work. Retrieved October, 2008, from http://solar.coolerplanet.com/Content/Photovoltaic.aspx
Wesley United Methodist Church
Wesley United Methodist Church
2008
Solar Panel Feasibility Study
March 5, 2009
DSC01919_edited.jpgBrian Bates bsbates@wpi.edu
Dillon Buchanan dillonb@wpi.edu
Stephen Mueller smueller@wpi.edu
Thomas Parenteau tap@wpi.edu Total Pages: 126 Worcester Polytechnic Institute 100 Institute Road Worcester, MA 01609 +1-508-831-5000
Solar Panel Feasibility Study At Wesley United Methodist Church, Worcester An Interactive Qualifying Project Report submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE in partial fulfillment of the requirements for the Degree of Bachelor of Science by Brian Bates Dillon Buchanan Stephen Mueller Thomas Parenteau Date: March 5, 2009 Report submitted to: Faculty Project Advisors: Prof. Peter H. Hansen Prof. Alex Emanuel Wesley United Methodist Church Project Liaison: Lorna Mattus-Merrill This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its web site without editorial or peer review.
Abstract
This project evaluated the feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church in Worcester, MA. Analysis of the site, weather data, and economic incentives available to church facilitated the creation of a model that could predict the value of a photovoltaic system as an economic investment. This analysis resulted in a long payback period, but projections using this model indicate significant changes as the price of photovoltaic panels continue to fall.
Executive Summary
The Wesley United Methodist Church, located in Worcester, Massachusetts, was interested in the feasibility of installing a photovoltaic panel system on its roof. The church incurs a costly electric bill, which, coupled with a gas heating bill, imposes a significant financial burden. Concerned that the costs of electricity would only rise in the future, the church’s business administrator began looking into alternative energy options. The church has a prominent, south-facing roof space, and its leadership was particularly interested in determining if a solar power system could be installed to utilize this space. The overall goal of this project was to create an economic model that could predict the feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church. Creating a model tailored to the church was important because of the church’s status as a non-taxable institution. This meant that traditional models for estimating the feasibility of such a system, which included numerous tax benefits and deductions, would not be applicable. The secondary goal of this project was to assess the social implications of installing a photovoltaic system on the church. We wanted to determine how much the church’s congregation knew about solar panels, as well as how they felt about installing such a system on their church. If installed, the panels may be visible from the ground, which could have a negative aesthetic impact for some congregation members. Besides this, we also wanted to determine how non-economic factors, such as green stewardship and carbon footprint, would affect the overall feasibility of a solar panel installation.
The task of determining the overall feasibility of installing a photovoltaic system was divided into five sections. The first section, site analysis, was concerned with obtaining the physical layout of the roof space suitable for panel placement, as well as determining relevant meteorological data that was needed for energy calculations. The goal of this section was to create an accurate map of where panels could be placed on the roof, as well as how much energy could be gathered given Worcester’s
climate. The second section, possible solar panels and placements, dealt with determining the criteria and system that would be used to select the best panel equipment for the church. The third section investigated what effect different orientations and configurations of the panels would have on the amount of energy that could be produced. The goal of this section was to determine the best tilt angle for the solar panels as well as the most effective inter-panel spacing. Economic feasibility of the systems, the fourth section, investigated what economic factors and assumptions should be used in order to create an accurate economic model of the solar panel system as an investment vehicle. In the final section, social implications, our objective was to determine what social factors might come into play that could help or hinder the support for the installation of a photovoltaic system. From our analysis of Worcester weather data and the roof of the church, we determined that the maximum installation size possible on the roof of the church was approximately 25kW. From the 420 m2 of flat space on the roof, we found that 200 m2 was suitable for installing solar panels. This was because shadows from surrounding portions of the roof would make placing panels in these areas impractical. Determining shadowed areas was done by taking measurements early and late in the day, when shadows were most prevalent.
Our solar panel selection process suggested that the most suitable panel for an installation on the church would be the Kyocera KC200GT. This panel had an efficiency rating of 15% and an overall cost per watt of $4.35, making it the most cost effective panel of those investigated. The power inverter chosen, which was needed to convert the DC electricity from the panels into AC electricity that the church could use, was the Sunny Boy SB7000US. This inverter was chosen because of its 95% efficiency coupled with its ability to be scaled to different system sizes. Using this inverter, we estimated a total DC to AC conversion factor of 79.49%. This factor was a result of the inverter efficiency as well as the efficiency of the AC and DC wiring and connections to the system. Combining the efficiency of the solar
panels and the efficiency of the DC to AC conversion, we calculated an overall system efficiency of 11.92%. Tilting the solar panels at an angle of 42 degrees allowed them to capture the most sunlight. The yearly average of daily irradiation per square meter at this angle was 4.69 kWh/m2/day. With an overall system efficiency of 11.92%, this led to an average monthly electrical generation of 2838 kWh for a 25kW system. Given that the church consumes an average of 9500 kWh, a system of maximum size would cover only 30% of the church’s electricity needs. Through a combination of the equipment chosen, estimates on installation costs gathered from installers, and state averages for similar installations, we found that installing a photovoltaic system on the church would cost approximately $8.00 per watt. Using the maximum size of 25kW would produce a raw system cost of $200,000. However, a number of different system sizes were evaluated, ranging from 10kW to 25kW. Given an overall price of a photovoltaic system, it was important to determine if this price would translate into an effective investment. The important factors in calculating the investment potential of such a system included: the savings in electricity costs, other income such as renewable energy credits, the rebates and incentives available, how the investment will be financed, and expected trends in inflation and energy costs. The electricity savings produced by a photovoltaic system are directly proportional to the system’s size because of the church’s contract with the electric utility. Renewable energy credits could generate additional revenues of $0.03 per kWh, but from correspondences with the Mass Energy Consumers Alliance we found that these contracts may not be available in the future. Because the church is a non-taxable institution, the only significant incentive for installing a solar panel system is the rebate offered by Commonwealth Solar. For installations under 25kW, the rebate offers a price reduction of $3.25 per watt. In order for to receive the rebate, however, the installation must be done by an approved solar panel installation company.
2008
Solar Panel Feasibility Study
March 5, 2009
DSC01919_edited.jpgBrian Bates bsbates@wpi.edu
Dillon Buchanan dillonb@wpi.edu
Stephen Mueller smueller@wpi.edu
Thomas Parenteau tap@wpi.edu Total Pages: 126 Worcester Polytechnic Institute 100 Institute Road Worcester, MA 01609 +1-508-831-5000
Solar Panel Feasibility Study At Wesley United Methodist Church, Worcester An Interactive Qualifying Project Report submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE in partial fulfillment of the requirements for the Degree of Bachelor of Science by Brian Bates Dillon Buchanan Stephen Mueller Thomas Parenteau Date: March 5, 2009 Report submitted to: Faculty Project Advisors: Prof. Peter H. Hansen Prof. Alex Emanuel Wesley United Methodist Church Project Liaison: Lorna Mattus-Merrill This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its web site without editorial or peer review.
Abstract
This project evaluated the feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church in Worcester, MA. Analysis of the site, weather data, and economic incentives available to church facilitated the creation of a model that could predict the value of a photovoltaic system as an economic investment. This analysis resulted in a long payback period, but projections using this model indicate significant changes as the price of photovoltaic panels continue to fall.
Executive Summary
The Wesley United Methodist Church, located in Worcester, Massachusetts, was interested in the feasibility of installing a photovoltaic panel system on its roof. The church incurs a costly electric bill, which, coupled with a gas heating bill, imposes a significant financial burden. Concerned that the costs of electricity would only rise in the future, the church’s business administrator began looking into alternative energy options. The church has a prominent, south-facing roof space, and its leadership was particularly interested in determining if a solar power system could be installed to utilize this space. The overall goal of this project was to create an economic model that could predict the feasibility of installing a photovoltaic system on the roof of the Wesley United Methodist Church. Creating a model tailored to the church was important because of the church’s status as a non-taxable institution. This meant that traditional models for estimating the feasibility of such a system, which included numerous tax benefits and deductions, would not be applicable. The secondary goal of this project was to assess the social implications of installing a photovoltaic system on the church. We wanted to determine how much the church’s congregation knew about solar panels, as well as how they felt about installing such a system on their church. If installed, the panels may be visible from the ground, which could have a negative aesthetic impact for some congregation members. Besides this, we also wanted to determine how non-economic factors, such as green stewardship and carbon footprint, would affect the overall feasibility of a solar panel installation.
The task of determining the overall feasibility of installing a photovoltaic system was divided into five sections. The first section, site analysis, was concerned with obtaining the physical layout of the roof space suitable for panel placement, as well as determining relevant meteorological data that was needed for energy calculations. The goal of this section was to create an accurate map of where panels could be placed on the roof, as well as how much energy could be gathered given Worcester’s
climate. The second section, possible solar panels and placements, dealt with determining the criteria and system that would be used to select the best panel equipment for the church. The third section investigated what effect different orientations and configurations of the panels would have on the amount of energy that could be produced. The goal of this section was to determine the best tilt angle for the solar panels as well as the most effective inter-panel spacing. Economic feasibility of the systems, the fourth section, investigated what economic factors and assumptions should be used in order to create an accurate economic model of the solar panel system as an investment vehicle. In the final section, social implications, our objective was to determine what social factors might come into play that could help or hinder the support for the installation of a photovoltaic system. From our analysis of Worcester weather data and the roof of the church, we determined that the maximum installation size possible on the roof of the church was approximately 25kW. From the 420 m2 of flat space on the roof, we found that 200 m2 was suitable for installing solar panels. This was because shadows from surrounding portions of the roof would make placing panels in these areas impractical. Determining shadowed areas was done by taking measurements early and late in the day, when shadows were most prevalent.
Our solar panel selection process suggested that the most suitable panel for an installation on the church would be the Kyocera KC200GT. This panel had an efficiency rating of 15% and an overall cost per watt of $4.35, making it the most cost effective panel of those investigated. The power inverter chosen, which was needed to convert the DC electricity from the panels into AC electricity that the church could use, was the Sunny Boy SB7000US. This inverter was chosen because of its 95% efficiency coupled with its ability to be scaled to different system sizes. Using this inverter, we estimated a total DC to AC conversion factor of 79.49%. This factor was a result of the inverter efficiency as well as the efficiency of the AC and DC wiring and connections to the system. Combining the efficiency of the solar
panels and the efficiency of the DC to AC conversion, we calculated an overall system efficiency of 11.92%. Tilting the solar panels at an angle of 42 degrees allowed them to capture the most sunlight. The yearly average of daily irradiation per square meter at this angle was 4.69 kWh/m2/day. With an overall system efficiency of 11.92%, this led to an average monthly electrical generation of 2838 kWh for a 25kW system. Given that the church consumes an average of 9500 kWh, a system of maximum size would cover only 30% of the church’s electricity needs. Through a combination of the equipment chosen, estimates on installation costs gathered from installers, and state averages for similar installations, we found that installing a photovoltaic system on the church would cost approximately $8.00 per watt. Using the maximum size of 25kW would produce a raw system cost of $200,000. However, a number of different system sizes were evaluated, ranging from 10kW to 25kW. Given an overall price of a photovoltaic system, it was important to determine if this price would translate into an effective investment. The important factors in calculating the investment potential of such a system included: the savings in electricity costs, other income such as renewable energy credits, the rebates and incentives available, how the investment will be financed, and expected trends in inflation and energy costs. The electricity savings produced by a photovoltaic system are directly proportional to the system’s size because of the church’s contract with the electric utility. Renewable energy credits could generate additional revenues of $0.03 per kWh, but from correspondences with the Mass Energy Consumers Alliance we found that these contracts may not be available in the future. Because the church is a non-taxable institution, the only significant incentive for installing a solar panel system is the rebate offered by Commonwealth Solar. For installations under 25kW, the rebate offers a price reduction of $3.25 per watt. In order for to receive the rebate, however, the installation must be done by an approved solar panel installation company.
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