Santa Rita Jail integrates solar electric generation and energy efficiency

Alameda County commissioned PowerLight in early 2001 to help reduce the Santa Rita Jail's electric utility bill in two ways.

First, a 1.14-MW photovoltaic array displaced utility electricity with clean on-site solar power. Secondly, the facility's overall need for electricity was reduced through a combination of added insulation from the solar roof tiles and a comprehensive upgrade of the jail's central plant, including state-of-the-art cooling equipment and controls. CMS Viron Energy Services, an engineering-based energy services and performance-contracting company, implemented the central plant upgrades.

The combined on-site solar power and energy-efficiency upgrades delivered impressive net savings to the county. The combined project reduced the facility's peak summer demand of grid-generated electricity by 25 percent.

The Santa Rita Jail project diverts nearly 2 million kWh of annual electricity consumption from California's electric grid. Those savings benefit state consumers by reducing grid power purchases, most of which occur during peak electrical demand hours at times when state transmission lines are the most constrained.