Green Energy Times, October 2017
By George Harvey
The Plainfield Elementary School, in Meriden, New Hampshire, is now being supplied with electricity from its own solar array. It was installed by Norwich Solar Technologies (NST), of White River Junction, Vermont, in the early autumn of this year.
The solar array is made up of 378 photovoltaic (PV) panels, each of 355 watts, giving it a capacity of 134,190 watts (DC). It stands on a piece of property across the road from the school building itself, behind the parking lot.
There was some initial concern over the siting from local residents, as often is the case with such installations. The main problem was a question of what impact the array would have on a local hiking trail. NST presented three design alternatives, and after considering the concerns, offered an approach combining their elements.
The School Board entered into an agreement with NST in the first week of May. Soon after, the issue was taken up by the town’s Zoning Board and the Planning Board. With their approvals, construction was undertaken as a summer project.
The array is installed behind the meter. This means that the school can draw electricity directly from the array. It is still on the electric grid, and so can draw electricity from that source any time the array is not producing sufficient power. Excess electricity produced by the array goes to the grid under net metering.
All of the design, permitting, and construction of the array was done by NST. The company will be around a while longer, because it remains responsible for system operation and maintenance of the system.
There were details of the system that are not immediately apparent, when a person casually thinks about an ordinary PV installation at an existing site. In this case, the interconnection and system upgrades were not trivial. The school needed a new transformer, as well. The cost of these upgrades was about $80,000.
Non-profit organizations, including public schools, cannot benefit from the incentives that are available to those who pay taxes. A for-profit partner is normally brought in to help with financing for this reason, and this produces financial benefits for all. In this case, Barrington Power, which specializes in such financing, provided the services, and will own the system for at least the first several years of operation.
Barrington Power entered into a 25-year power purchase agreement with the school, under the terms of which the cost of electricity is reduced by 5%. The agreement also specifies dates at which the school can purchase the array at a fair market value.
The Plainfield School array is expected to generate about 160,000-kilowatt hours of electricity each year. This will offset close to 100% of the school’s electric use, which costs about $24,000 each year. Generating that much power from fossil fuels would produce about 115,000 pounds of carbon dioxide.