Nation's Largest Solar Roof Dedicated in Dublin, CA

the nation’s largest rooftop solar electric system—located atop the Santa Rita Jail in Dublin, California.

The 1.18 MW photovoltaic (PV) system is an expansion of a 640 kW PV system that was completed in the summer of 2001. The PowerGuard^® system, which covers approximately 3 acres (1.2 ha) of the jail’s roof, was built by the PowerLight Corporation of Berkeley. The patented solar roof tiles insulate and protect the roof while generating electricity from sunlight. The PowerGuard tiles are fabricated with PV cells produced by both AstroPower and BP Solar. The system has reduced the jail’s peak summer demand consumption of grid-generated electricity by 35% and is projected to save Alameda County approximately $425,000 per year—or $15 million over the 25-year life of the project. The rooftop system provides enough electricity to power about 1,000 homes.