Monday marked an important day for the California solar industry as AT&T and SunEdison introduced a new San Diego, California rooftop solar energy installation that is expected to produce 420,000 kilowatt-hours (kWh) of energy during its first year of operation. According to MarketWatch, the system will generate over 7.7 million kWh of energy over a 20-year lifespan — enough to power 720 homes in the United States each year.

The San Diego project is part of a larger contract between the two companies to install five other rooftop systems in five other California cities: Dunnigan, Commerce, Mojave, Santa Ana and West Sacramento. These five solar projects, along with the recently completed San Diego project, are expected to add a combined two megawatts of solar energy capacity to California, which AT&T will purchase to offset the company’s own grid demand. Under the power purchasing agreement (PPA) between the two, SunEdison will build, monitor and maintain all six installations. Combined, the six systems are expected to prevent 62 million pounds of CO2 from infiltrating the air. Construction of all projects are set to begin by the second quarter of fiscal year 2011.