Figure 23: 25kW System Energy Production

Figure 23: 25kW System Energy Production The chart above depicts the energy consumed by The Wesley United Methodist Church, seen in blue, and the electricity produced by the 25kW solar array, seen in red. The total “net” usage is seen in green which is the difference between the energy consumed and the energy produced.

Figure 24: 25kW System Cash Flow with Volunteer Installation Figure 8 depicts the total cash flow of the 25kW array with volunteer installation. The figure describes the trend of savings from the initial purchase in year one to the life expectency of a solar array, year 25.
7.6 Assessment:
Revisiting the scenarios above, cost of installation is the single most important factor in whether a system will be feasible. Currently, the cost-per-watt of solar panels is generally fixed at $4-$5. This allows minor room to reduce the cost. However, because installation is not necessarily a fixed cost and most of the work can be done by knowledgeable volunteers it is possible to keep this cost much lower.
Another noticeable result of analyzing these scenarios is that the systems of varying sizes all have a break-even point of approximately nineteen years. The main reason for this phenomenon is the fact that larger arrays, despite their greater initial investment, recover savings much quicker because of their greater electricity production. The 25kW array may generate $164,997.40 in the course of 25 years compared to a smaller, 10kW array which may only produce $65,998.96 of revenue. This observation
displays the fact that a larger solar array is much more beneficial in the long term; however a small one is financially easier in the short term.
7.7 Sensitivity Analysis
Although we have determined that a largest array is the optimal scenario for the production of electricity the nine-teen year break-even point is near the system life expectancy of 20-25 years. However the cost of solar cells is constantly decreasing. Based on discussions with solar manufacturers and installers, it is expected that costs for solar panels will fall quickly in the next three to five years and the payback period will thus decrease rapidly. To illustrate the effect influence lower costs on the solar market we decided to create a sensitivity analysis. This analysis below offers a fifth scenario that projects possible costs and efficiencies of solar panels in five years. The following is a scenario assumes that in the future, technology will reduce the cost-per-watt of a solar panel from $4.30 to $2.00 and increase the solar cell efficiency from 15% to 20%. The result is a dramatic drop in the amount of time it takes to break-even. The period of time necessary to break-even drops from nineteen years to only nine and the number of panels required to generate the same amount of electricity is reduced from 117 panels to 88. The reduction in the number of panels also reduces the need to install solar panels in sub-optimal locations.

Figure 25: Futuristic 25kW System Cash Flow Figure 9 depicts the total cash flow of a 25kW array purchased in five years. The figure describes the trend of savings from the initial purchase in year one to the life expectency of a solar array, year 25.

Figure 26: The Effect of Waiting 5 Years The chart above depicts the outcome if a 25kW system, scenario three, was purchased in the present time period and if a 25kW system was purchased in five years using the data described above. As the results in figure 10 clearly demonstrate, it would be much more beneficial, economically, to implement a 25kW system after five years rather than at the current time period.
8. Social and Environmental Impact
The significance of solar panel systems go far beyond financial factors. Alternative forms of energy are important to the sustainability of our planet. This section identifies the social and environmental impacts that a solar panel installation would have on the church and what we have done to disseminate information about solar panel installations.
8.1 Effects on Carbon Footprint
A Carbon footprint is a measurement of the impact a person or a building has on the environment. It is usually represented as the number of tons of carbon dioxide released into the atmosphere by things such as power plants, cars, or burning heating oil. Based on information available from the Global Footprint Network, current levels of emissions exceed the capacity that the earth is able to absorb. This rate has been sharply increasing since the 1960s.41 Finding solutions to the problem of increased emissions is critical to environmental sustainability. However, offsetting the world’s carbon emissions by planting trees isn’t an efficient solution to the problem of increased emissions. A better solution is reducing the emissions themselves. Reduction of emissions requires cutting back the use of fossil fuels. This means driving less, using cars that are more efficient, and meeting high standards for emissions testing. It also means using less electricity, and when possible looking for ‘green’ alternatives. Sources of environmentally friendly electricity include solar PV, wind energy, and hydroelectric; although hydroelectric plants significantly disrupt the river upon which they are built.
41 Global Footprint Network. Globalfootprintnetwork.com. [Online] [Cited: December 2, 2008.] http://www.footprintnetwork.org/en/index.php/GFN/page/carbon_footprint/.
The church’s carbon footprint is primarily made up of the electricity it consumes, and the natural gas used for heating. Based on the formulas used by the Global Footprint Network the annual
electricity consumption creates 59 tons of carbon dioxide.42 The total amount of carbon dioxide created by or on behalf of the church is at least 67 tons of CO2 emissions per year.2 If the church were to install a 25kW solar array, they would significantly reduce the their annual emissions to 39 tons of CO2, a thirty three percent reduction.
42 Global Footprint Network. Globalfootprintnetwork.com. [Online] http://www.carbonfootprint.com/carbonfootprint.html 43 Harper Collins Publishers. (2009). The Green Bible. Retrieved 3/1, 2009 from http://greenletterbible.com/
8.2 Environmental Stewardship
Wesley United Methodist Church commissioned this study of green technology as an expression of its commitment towards “environmental stewardship.” Many of the individuals who participate in the church feel that it is their responsibility to the community to contribute to the adoption of clean energy. For that reason, the implementation of a solar array would not only reduce green house emissions, but also spread awareness to the wider community and inspire other community members to follow suit. As stewards of the Earth, a church could send a powerful message to the community by acting on these values in their place of worship.
Green stewardship is rapidly becoming a popular topic in the Christian community. There is a new bible that has been printed called the “Green Bible”. It highlights eco-friendly passages in green and has an index in the back where one can look up “green” passages. It is said that the “Green Bible sets out an urgent agenda for the Christian community.”43 One particularly relevant passage from Leviticus is as follows, “You shall not strip your vineyard bare, or gather the fallen grapes of your vineyard; you shall leave them for the poor and the alien: I am the Lord your God”. Another moving passage in support of green stewardship is from Psalm 24, “The earth is the Lord’s and everything in it, the world, and all who live in it.”
Green stewardship is a movement within the church that is rapidly gaining momentum as more and more Christians become aware of the threat humans pose to the planet. As the earth’s destruction continues, many are starting to feel it is part of their calling as followers of God to help. The city of Worcester has many churches of many faiths each concerned about the cost of rising electricity as well as the benefits of helping the environment. If the Wesley United Methodist Church were to decide to implement a solar system, it would be recognized as one of the first churches in the area to do so and demonstrate its leadership as an environmental steward in the community. If the implementation of green energy proves to be beneficial the Wesley United Methodist Church will become an example to those in Worcester and New England.
8.3 Informational Brochure
An informational brochure has been created to spread information to the church about the benefits of solar panel installations. Our correspondence with a Methodist Church from Maine showed us that the spread of information about a solar panel project can greatly reduce opposition and build support for this costly expenditure. The brochure captures the essence of our results. It has financial information, including a graph about the amount of energy produced with a large scale system and a graph showing how the payback period is directly related to the system cost per watt. The brochure also includes a couple of passages from the bible that support the concept of green stewardship and accompanying pictures of God’s magnificent creation. The brochure can be found in Appendix M: Informational Brochure.
8.4 Survey
After our final presentation, given on March 1, 2009, we handed out a brief survey to those who were in attendance (Appendix N). The audience consisted primarily but not exclusively of members of the Board of Trustees and Finance Committee at Wesley. There were only fourteen people in
attendance, so the survey is of little statistical value; however it has helped us to realize some of the general perceptions held by the congregation. All fourteen people responded they felt that investment in alternative energy is important, however their reasons for this answer varied. Some cited green stewardship as their primary reason, while others pointed to the fact that there is a finite supply of fossil fuels. Still others felt that alternative energy was important so that the country could become independent of foreign oil. Most mentioned that it was important to be environmentally conscious and many responses included a combination of these reasons. In response to the second question, which asked about what the public’s perception of a solar panel installation on Wesley United Methodist Church would be, the answers were again unanimous. All responses stated that the public’s view of such an installation would be positive. One responder felt that it would have limited affect, and only be slightly positive, while many responded that this would be “very positive”, “forward thinking”, and “green.” The last two questions had a wider range of responses than the first two. When asked whether or not a solar panel installation should be pursued even if there was no economic gain, most said that it should be pursued for environmental reasons, however, there were a few responses that said that the only factor that was important to them was the financial savings.
Finally, on the last question, which asked whether or not Wesley United Methodist Church should pursue a solar installation now, in the future, or not at all, there was the widest disparity of answers. A number of people felt that the church should wait for five years and then reevaluate the situation, while others felt that church should do more research about it now. Some people felt that the church should absolutely pursue it now, while there was one response that said it should not be pursued at all.
While everyone in attendance of our final presentation felt that alternative energy was important, it can be seen by looking at the remainder of the questions that this belief was weighted differently by each person. Looking into the future, the congregation will have a lot to debate as they try to decide what to do with the results of this project.

9. Conclusions and Recommendations
The benefits of solar panel installations are numerous, ranging from green stewardship to reducing the church’s carbon footprint, and from building a strong public image for the church to reducing the church’s monthly electricity bills. The feasibility of such a system is not determined by a financial analysis alone. Based on current prices, a solar panel system installed at Wesley United Methodist church would have a nine-teen year payback period. We recommend that the church strongly weigh the positive impacts of solar panels alongside the economic feasibility of installation. With the present conditions, it is unlikely that a solar panel installation will lose money over the lifetime of the system; however, it requires a large capital investment and has a slow payback. The church should monitor future the economic conditions using the “Simplified Economics Spreadsheet for Wesley United Methodist Church” that we have provided to get an estimate of economic feasibility of a solar power system. When it is determined that the benefits from a solar panel installation outweigh its drawbacks, such as when the cost per watt drops below a threshold price, the church should follow the procedure outlined below:
1. Form a committee of people who are interested in seeing this project carried forward. 2. Have the committee hold meetings/focus groups with interested members of the congregation to educate the congregation about solar panels and answer any concerns. The committee can use our presentation, brochure, and any of the other materials in this report. 3. Have the committee members contact three to five installers and go through the bidding process as we have outlined.
4. Use the graph “Simplified Economics Spreadsheet for Wesley United Methodist Church” with current data to determine the financial feasibility of this system.
After estimates have been received, the selection process can begin. After choosing an installer, the rest of the process, such as acquiring the Commonwealth Solar rebate and fulfilling permit obligations will be handed by the chosen installer. Hopefully, as solar panel technology continues to drop in price, the church will be able to reap the benefits of clean, renewable energy.
Appendix A: Solar Panel Tilt Analysis
Analysis of the installation orientation of solar panels is crucial to getting the highest power output from the solar panels. Solar panels receive the most energy from the sun when the surface of the solar panel is perpendicular to the sun’s rays. Some solar panels track the position of the sun. The surface of these panels is always perpendicular to the sun, giving tracking panels the highest output of any mounting system. However, the increase in efficiency does not come without a cost. Tracking mounting systems are significantly more expensive than other mounting options and are also a lot more likely to break.
In some cases, solar panels are mounted directly on the roof. However, this is also a sub-optimal solution because the sun will never be perpendicular to the solar panel. In Worcester, MA, the sun is at an angle of 80° above the horizon at noon during the summer and only 30° above the horizon at noon during the winter. 44 It is typically recommended to mount solar panels with a tilt angle that is equal to the latitude for the site location.45 Another approach is to use a solar panel mounting structure that can be changed twice a year, realigning the panel during the winter and the summer. It is essential to predict how much energy will be generated from different panel orientations in order to compare these different solutions and predict the overall energy output from the system. To do this, one must be able to accurately predict the power from the solar panel at any time.
44 GAISMA. [Online] www.gaisma.com. 45 Lenardic, Denis. Solar radiation estimation and site analysis. Atomstromfreie Website. [Online] Greenpeace Energy, September 13, 2008. http://www.pvresources.com/en/location.php.




Θtilt
Θtilt
Θinc
Θsun
The tilt angle is represented above by Θtilt, which is the angle between the solar panel and the ground. This angle is also the angle between the vertical y-axis and a vector normal to the surface of the solar panel. It is shown in both places in the diagram above. The angle between the y-axis and a vector representing the sun’s rays coming onto the surface of the solar panel is represented by Θsun. Subtracting these two values yields the value for Looking at this as a two dimensional problem the amount of energy from the sun that hits the solar panel at any given moment is related to the size of the solar panel times the cosine of the incident angle between the solar panel and the sun’s rays. The incidental power, or actual power, can be determined based on the amount of power that would land on the surface of the solar panel using the equation below.
Since the sun moves not only vertically in the sky but also across the sky from east to west, this concept must be extended to three dimensions in order to get the instantaneous power throughout the day.
To determine what the optimal tilt angle for solar panel installation is, a group from Taiwan created a simulation that used a Genetic Algorithm (23). They simulated the amount of power
generated by the solar panel at five minute intervals using historic weather data for five years. They could then estimate the amount of energy that would have been generated by the solar panels over that time period at a given tilt angle. To find the optimal tilt angle, they created a pool of genes (binary strings) that represented the tilt angle. With each iteration of the program, a selection process is applied, selecting only the best performing solution. The genes then reproduce. Some are direct copies of the previous generation, other experience a mutation, where one bit changes between 0 and 1. Still others experience crossing over, where a substring from one gene is switched with a substring of another. With each generation, the program gets closer to finding an optimal solution. A similar experiment could be done for Worcester, MA, however the difference in power output between this new solution and the usual recommendation of using the Latitude as your angle is likely to be insignificant, as was the case in this experiment.
Appendix B: Recommended Bidding Process
The first step in the bidding process is defining the system the church wants. This needs to include all the specific details including the amount of power the church hopes to generate, the preferred brands of panels, and the DC/AC inverter. This is also the time to determine the areas on the roof which are suitable for mounting panels. Much of the decision should be made by this point as to what the church is willing to install and pay for in order to make providing information to potential contractors simpler. The second step is to gather a list of local contractors that are known to install similar systems in the area. This is as simple as contacting the MTC for a list of installers in the Worcester area or using a phonebook’s yellow pages. It is important to get a list of installers and to determine which of them are interested in putting in a bid for an installation of this size. After a simple phone conversation with each of them, the church should have a list of contractors that are interested in bidding on their project. These first two steps are mostly covered by this report. The report has a recommended system and location on the roof already selected to meet the needs of the church. The report also includes a list of potential installers in the Worcester area. To complete these two steps, the church only needs to agree to the recommended system and call the installers to make a list of those that are interested. The third step in the process is to draft formal letters requesting bids. These letters need to include very detailed information to simplify the process. First of all, there need to be timetables involved. They should include a deadline for the church to receive the quotes from installers, as well as preferred beginning and ending dates for the installation. It’s also important to give all the details determined in step one of the process. It is best to give as much information as possible so that the church does not need to field calls from contractors seeking more information.