Riverside County is expected to become the biggest solar-energy producer among all the counties in the nation this year.

A $54.6 million solar buildup will bring clean-energy-producing shade structures and ground systems to two sheriff’s stations and eight other county facilities.

Once the facilities are up and running by the end of 2015, they are expected to generate 12.25 megawatts – enough electricity to serve the equivalent of about 2,600 homes.

What’s more, taxpayers will benefit. The county will save enough on its Southern California Edison bills to cover its loan payments for the solar systems.

“It would be great to break even, but to bring in additional money, was like, ‘Wow,’ said Janet Purchase, an energy manager for county’s Economic Development Agency.

Purchase estimated that savings from the Edison bills will put the county $288,000 in the black after the first year. Over the 30-year life of the panels, the county is expected to save $118 million. That estimate takes into account future electricity rate increases.

If those estimates turn out to be too rosy, the county still should make money. The contract with OpTerra Energy Systems, the company installing the solar systems, guarantees savings averaging $127,000 a year over the 20-year loan period.

And, unlike large solar projects going up in the deserts of Riverside and San Bernardino counties, these smaller solar installations are not being built on undeveloped land, so they won’t affect wildlife habitat.

They will, however, give sheriff’s deputies, other county workers and citizens more shaded places to park. The photovoltaic panels will be installed on new shade structures being built in parking lots at nine facilities.

Sites include sheriff’s stations in Palm Desert and Perris, the animal shelters in San Jacinto and Jurupa Valley, the coroner’s office in Perris, the county hospital in Moreno Valley, the Ben Clark Training Center in Riverside, the administrative offices in Temecula, and a Mead Valley transportation facility.

The project also includes ground-mounted panels at the Brookside Materials Yard in Beaumont and the San Jacinto animal shelter.

The county is borrowing the $54.6 million to pay for the solar systems, which will be paid back over 20 years in a lease-purchase agreement with San Francisco-based OpTerra Energy Systems.

An OpTerra official stopped short of saying that Riverside County’s project is a tipping point for what industry officials call “distributive solar” – smaller systems on rooftops, shade structures and ground systems that make electricity where it is used.

While solar energy is becoming more affordable, the county’s project looks good because of several factors, said Roger Chung, an OpTerra project finance manager. Riverside County is benefiting from a loan with a low interest rate of 3.3 percent, California’s higher costs for electricity, ample sunshine and declining prices for solar panels, Chung said.

Other agencies may get more savings by becoming more energy efficient, Chung said.

Ken Johnson, a vice president with the national Solar Energy Industries Association, said Riverside County’s program puts it ahead of all other U.S. counties.

“There are some variations of this (Riverside County) program in Massachusetts, North Carolina and Virginia,” he said. “But we believe this would be the largest project of its kind involving a county government.”

The Riverside County project is made possible by a California law that makes solar installation more feasible for local government.

The law requires Edison to give the county credit for all electricity made at the 10 facilities as long as the amount generated does not exceed the county’s total use for its buildings that are served by the utility.

This rule gets the county around a major financial hurdle.

In California, utilities generally do not give solar system owners credit for any amount of electricity that is more than what is used at the property where the system is installed.

For example, if a home rooftop system makes more kilowatt-hours than are used by the household, the owner essentially winds up making a free contribution to the electrical energy grid. That’s why homeowners are advised not to install more solar panels than are needed for their home use.

The county, however, doesn’t have that limit. Its biggest installation will be ground systems at the materials yard in Beaumont that will make enough electricity for nearly a thousand homes. But just about 5 percent of the electricity produced there will be used by the yard.

Contact the writer: 951-368-9471 or ddanelski@pe.com