Photovoltaic=Light + Electricity
Chapman's 46.8kW photovoltaic system, comprised of 208 Sunpower SPR-225 Modules, generates 61,000 kWh of clean power per year, offsetting Chapman's total power consumption of 65,000-68,000 kWh per year. The system is grid-connected, sending excess power back to the utility during times of peak production.

Economics
Chapman received a LORI (Large Onsite Renewables Initiative) grant from the Massachusetts Technology Collaborative for the system. That grant, combined with federal and state tax incentives, has allowed us to calculate a five-year payback term for the system. We expect the panels to have a lifetime of approximately 40 years, giving us 35 years of free power after the system has paid for itself.

How It Works
Photovoltaic cells are made of silicon semiconductors. When light hits the semiconductor, energy is absorbed and electrons are freed and induced to travel through an electrical circuit, creating the current. DC power generated by an array is then fed into an inverter, which outputs AC power for building use or to be fed back into the grid.