Edwin L. Aguirre
Cities and towns across the country are trying to come up with green ways to cut energy costs and save natural resources. For the Chelmsford Water District, the solution was to install a photovoltaic (PV) system that will harness enough solar energy to power the district’s entire Crooked Spring Water Treatment Plant during peak operating hours.
The district’s proposal was so well received at the state’s Department of Environmental Protection that the agency appropriated $3,783,000 of federal stimulus money to finance the project, which will create one of the largest municipal solar projects on the East Coast.
Patrick Retelle, a graduate student in UMass Lowell’s solar engineering program, helped the district come up with a “shovel-ready” plan of using 2,300 PV panels that are estimated to generate about 588,000 kilowatt-hours of electricity per year.
“Pat volunteered his time to do the analysis for the district’s grant application through Madeline Snow of the University’s Lowell Center for Sustainable Production,” says Mechanical Engineering Prof. John Duffy, coordinator of UMass Lowell’s solar engineering graduate program. “Pat is also using the analysis for his project course as part of his master’s degree requirements. It’s a service-learning project. I was his advisor, but he did most of the work on his own.”
Retelle says he worked with Todd Melanson, the water district’s environmental compliance manager, to assess the feasibility of installing a PV system.
“First, I made sure that very efficient pumps and equipment were being used at the treatment plant. Then, I determined the plant’s overall square footage of usable space, the site’s orientation to true south and potential shading issues, and the number of panels that could physically fit at varying tilt angles,” he says. “Afterward, I estimated the power outputs for various PV module types as well as the number of additional components needed such as DC to AC inverters and combiners. Finally, I calculated the project’s payback, which I estimated to be at least 12 years.”
Retelle submitted his report to Melanson and had a couple of meetings with him.
“Todd is the champion of the project and without him this would not be a reality,” says Retelle. “I supported him in the technical aspects of the project.”
In addition to its goal of energy self-reliance, the project will help reduce the water district’s carbon footprint by 132 tons of carbon dioxide emission annually. This is equivalent to saving about 111 acres of forest each year.
Work on the project is expected to begin in July next year.