Onset Shared Solar Project

Boston Community Capital (BCC) is a nonprofit community development financial institution. Since 2008, BCC has helped low-income communities access the cost savings and price stability of solar power. The organization1 has developed and currently operates about 7 megawatts of solar photovoltaic systems across Massachusetts. Half of BCC’s solar projects are on-site, rooftop solar installations that serve affordable housing developments and community facilities. It has also developed three off-site shared solar facilities, which use virtual net metering (VNM) to provide benefits to customers unable to put solar on their own roofs.

The Onset Shared Solar Project is one of BCC’s off-site shared solar facilities. Onset is a historic waterfront community in the town of Wareham, MA, on the shore of Buzzards Bay. BCC has built two large, adjacent ground-mounted solar arrays there, on land leased from the Onset Water District. At 1 megawatt each, the arrays produce enough electricity to power about 450 homes annually. The electricity produced by the panels flows to the grid, and BCC earns net metering credits for every kilowatt-hour of electricity generated. BCC, in turn, sells those credits to 19 affordable housing developments at a discounted rate. The arrangement offsets the electricity costs of the property owner, typically in the common areas such as gathering rooms and hallways of an affordable housing development. In some cases, however, the properties are master-metered, meaning the property owner pays all of the tenants’ electricity costs.

BCC allocates net metering credits estimated to offset about 85 percent of a property owner’s annual electricity costs. These credits are sold at a 20 percent discount, for a minimum contract term of 10 years, providing an initial cost savings of about 17 percent; properties will save more if electricity rates go up. Even if electricity rates stay flat, the Onset Shared Solar Project will generate savings to the affordable housing providers of at least $1 million over 10 years.

In addition to serving 19 affordable housing developments served by the Onset arrays, BCC has developed a pilot program to directly offset the electricity bills of 56 residents of two of the affordable housing developments. For these residents, BCC aims to achieve a savings of 50 percent, or $500, off their annual electric bills.

This Onset Shared Solar Project demonstrates the potential of shared solar project models that use VNM to expand access to solar for affordable housing properties and lower electricity bills. It also highlights the opportunity, and some of the challenges, of using VNM to directly benefit the low-income residents of these properties.