ANTIOCH -- Solar panels are helping Delta Diablo Sanitation District generate big savings on its Pacific Gas & Electric bills.

Since May, almost 1,000 panels installed on nine individual carport structures covering a 75-space parking lot have been providing most of the electricity used by the district's adjacent two-story administration building.

"We paid on the order of $120,000 per year for electricity on that building," before the solar photovoltaics were installed, said Dean Eckerson, principal engineer for the district, which provides sewage treatment, household hazardous waste disposal services and street sweeping for 52,000 households in Antioch, Bay Point and Pittsburg.

Now, the district expects its yearly power costs will be about $10,000 for the administration building, which also includes laboratories for testing water quality of discharged wastewater, mechanical equipment repair and warehouse facilities.

On an annual basis, the district's 421-kilowatt solar project is expected to provide enough energy to power 58 single-family homes. It is the first solar project installed by the district, which is looking into adding a second such project on its property.

The panels, along with the carports that they sit upon, were installed over a six-month period at a total project cost of $2.85 million. A $650,000 grant from the California Solar Initiative, which is funded by ratepayers from PG&E, Southern California Edison and San Diego Gas & Electric, will help offset project costs over a five-year period.


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But beyond the grant money, the district will be saving more than $100,000 a year from lower PG&E bills, Eckerson said.

Having a solar system also lets the district export some of its surplus energy back to the grid.

"There are times of the day and the year when we over generate, and PG&E is crediting us the value back on the bill," he said.

Paying less for electricity is among many factors that the district will take into consideration when setting rates in the future. And while rates aren't expected to decrease going forward, having lower energy costs for the administrative building could potentially offset other rising operational costs.

"This lowers one portion of operating costs," Eckerson said. "Ultimately, it would be reflected in the rates, but it's just one component."

Plans are under way for a second solar project for the district's recycled water facility, which would provide up to 70 percent of the facility's energy needs.

Delta Diablo is among a growing number of PG&E customers deriving energy from the sun.

"We've connected solar facilities for more than 75,000 residences and businesses throughout our service area," PG&E spokesman Jason King said. "It is by far the most of any utility in the United States."

Contact Eve Mitchell at 925-779-7189. Follow her on Twitter.com/EastCounty_Girl.