Chris Rogge, left, director of solar design with Cromwell Environmental, and Nick Gardner, installer, mount several solar panels on the roof of the Douglas County Extension Office building in this November 2010 file photo. The units will supply about 15 percent of the building’s energy and will also be used for educational purposes.

A lack of sun didn’t keep a freshly installed photovoltaic system from generating energy this week.

Crews from Cromwell Environmental placed 20 solar panels on the south-facing roof of Douglas County Extension Office, 2110 Harper St. Along with producing 15 percent of the building’s electricity over the next 25 years, the system will be used as an educational tool for the extension office.

“This is just an energy-saving appliance,” said Aron Cromwell, a Lawrence city commissioner and CEO of the company contracted to install the panels.

The $20,000 system, a quarter of the cost of which will be covered by a Kansas State Energy Office grant, is one of three solar projects Douglas County installed this year.

This summer, solar thermal panels were installed at Douglas County Jail, 3601 E. 25th St., to heat water. In the fall, the county completed a similar system at the Douglas County Youth Services building in North Lawrence. The two combined for a $19,996 contract.

These projects are already cutting down on Douglas County’s utility bills, the county and city’s sustainability coordinator, Eileen Horn, said.

From the beginning of June to the end of September, the solar thermal panels at the jail shaved off $538.51 from its natural gas bill. One of the jail’s five hot water systems had its natural gas usage dropped by 70 percent.

Savings are on track to meet the projected eight-year payback of the jail’s five solar panels, Horn said. She called the solar panels a “smart, appropriate application of renewable energy.”

As for the panels going up this week on the extension office building, energy savings are expected to cover their expense over 16 years and avoid producing 261,000 pounds of carbon dioxide emissions over the next 25 years.

Beginning Wednesday, electricity was already trickling into the building.

Halfway through installing the panels on the extension office and under cloudy skies, crews switched on the solar panel inverter, a box that converts the solar panel’s direct current of electricity into the alternating current of electricity that is needed to power the building.

The meter read 33 watts.

“That’s enough for a compact fluorescent (light),” Cromwell said.