Energy Alton, an award-winning community group in Hampshire, had previously initiated the installation of photovoltaic solar panels on the roof of Alton library. It wanted to build on this success by installing solar panels on three secondary schools in the town, and brought in the National Energy Foundation as part of a Rural Community Energy Fund grant award to assess the potential and examine the financial case for installing PV.
We visited each school and identified suitable locations on different buildings across the three sites. We worked out which roofs were suitable for PV, the maximum size of array that could be installed, how much it would cost to purchase and install panels, how much electricity this would generate, and how long it would take for the investment to pay for itself.
Aerial photo of one of the schools
We also spoke to the local planning authorities to assess whether they would support planning applications to install PV, and what issues they would bear in mind in any decisions. We looked at different governance and legal structures for managing the installation and ownership of the panels, including legal contracts for leasing roof-space, as well as liability and insurance issues. We also explored network issues, and how Alton Energy or the schools would need to set up grid connections to export surplus electricity.
We worked out that the three schools could install photovoltaics with a peak output of up to 504 kW. Our modelling suggested this would generate 482 MWh a year of electricity, worth £42,000 (including Feed-In Tariff payments - the government’s main incentive for installing renewable energy).
Although Feed-In Tariffs have fallen dramatically in recent years, they still bolster the financial case for PV. Depending on the size of the arrays installed, these school projects stand to yield 6-10% a year – accepting that investors will not be able to get back their capital at the end of the project.
The capital cost of installing PV at the three schools would be repaid in 12 years for smaller arrays (up to 50 kWp, excluding discounting of future costs and revenues), or up to 15 years when future costs are discounted.
Regarding the best form of governance for managing the PV, we recommended establishing either a Community Benefit Society (which might be eligible for Social Investment Tax Relief) or a Cooperative Society.
Seasonal variation of PV (Credit: Transition Cambridge)