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.