Solar power in Alameda County

Solar photovoltaic (PV) power systems from PowerLight generate electricity for seven Alameda County facilities, including the Oakland Courthouse and the offices of county emergency services and environmental health services. The first and by far the largest project is the 1.18 megawatt (MW), convert|3|acre|m2|sing=on, solar array on the roof of the Santa Rita Jail.

anta Rita Jail

The Santa Rita Jail is one of the largest county jails in the USA. It houses 4,200 inmates and 500 staff near the suburb of Dublin, and its 1.18 MW installation is one of the largest solar roofs in the United States. [http://www.cleanedge.com/book/Chapter1_The_Clean_Tech_Revolution.pdf Solar Energy: Scaling Up Manufacturing and Driving Down Costs] p. 41.]

When solar power was first considered for the jail in 2000, the economics were poor. Average electricity rates were less than 7 cents per kilowatt-hour, so in the first 500 kW phase of the project, PowerLight also offered energy efficiency improvements, such as a better water chiller for air-conditioning. The following year brought a summer of rolling blackouts and Enron market manipulation as California’s energy deregulation crisis hit, and electricity rates nearly doubled. Phase two didn't need any efficiency measures and added another 180 kW, and phase three (completed in 2002) involved an additional 500 kW.

PV panels now generate as much as half of the jail’s peak power on sunny summer afternoons. Throughout the year, solar contributes anaverage of 20% of the daytime electricity and 12% overall, since solar panels can’t harness any sun after dark.

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