Sitting atop FedEx’s 350,000 square foot distribution hub at Oakland International Airport lurks a real powerhouse. Almost the entire surface area of the roof is covered with shiny black solar panels and operates just like the solar cells you’d find on your calculator. The only noises that make it to the roof are the sounds from the huge jet engines of FedEx cargo planes and smaller transport vehicles down below. Otherwise, the solar arrays produce 904 kilowatts of electricity in near silence, enough to power 900 Bay Area homes and significantly reduce greenhouse gasses at the same time.

The Oakland hub solar array was designed and installed by PowerLight Corp., which is based right in Oakland’s backyard in Berkeley. PowerLight public relation’s representative Susan DeVico says that FedEx’s solar system is just one example of the many environmentally friendly power generators that PowerLight has designed and built around the Bay Area. Other locations include California State University East Bay, UC Berkeley Student Union, San Francisco’s Moscone Center, Microsoft’s Silicon Valley campus, and various vineyards in Napa and Santa Rosa.

The FedEx unit, however, is the largest corporately installed electric solar array in California, according to PowerLight. It covers 81,000 square feet, equivalent to one and a half football fields. PowerLight says the amount of greenhouse gasses the system will reduce over the course of its expected 30-year lifespan will be equivalent to planting 3,000 acres of trees or removing 2,100 cars. In the super-cramped Bay Area, that’s a lot of toxic gases we won’t have to breathe.

“FedEx is proud to lead our industry in committing to real, practical ways of reducing pollution, conserving fossil fuels and contributing to a greener world,” says Mitch Jackson, FedEx’s managing director of Corporate Environmental Programs.

At the heart of these solar arrays are photovoltaic panels. They take solar energy from the sun and covert it into the kind of electricity that comes out of electrical outlets in homes. The process consumes no environmentally un-friendly fossil fuels. In fact, the system installed on FedEx’s hub generates so much electricity and is so efficient that some of the power produced makes its way into other locations.

“When this system is putting out more power than the building is using, the power goes back into the grid and actually turns the meter backwards,” said Vice president of Sharp Solar Energy Solution Group Ron Kenedi in a press release.

Moscone Center’s solar array produces 675 kW of electricity, enough to power about 600 single-family homes. Microsoft’s Mountain View campus produces 480 kW, enough to power about 430 homes. Cal State University East Bay’s system produces slightly more than FedEx’s system at 1000 kW, but only provides about 30 percent of the university’s peak electrical needs.

PowerLight says these solar arrays benefit the environment by supplying emission-free electricity and avoiding having to purchase fossil fuel-generated electricity. In the end, this means cleaner air for the entire Bay Area.