The 205 kilowatt solar array atop the Department of Energy’s Forrestal Building will generate approximately 200 megawatt hours of electricity annually, providing up to 8 percent of the complex’s energy during peak hours.

The 205 kilowatt solar array atop the Department of Energy’s Forrestal Building will generate approximately 200 megawatt hours of electricity annually, providing up to 8 percent of the complex’s energy during peak hours.

Credit: Jeffrey Lee

Washington, D.C., Sept. 9 -- In an event that signifies the widening use of solar power nationwide, U.S. Department of Energy Secretary Samuel Bodman today inaugurated one of the largest solar electric photovoltaic systems in Washington, D.C., installed on the roof of the DOE’s Forrestal Building.

“The significance of this solar array is both practical and symbolic,” he said. “It provides real-world savings and improves the way the department consumes energy. And it is a symbol of America’s commitment to using the best available new technologies to confront the energy challenges we face today and will face tomorrow.”

The 205 kilowatt installation, which is about 40 to 50 times the size of a typical residential PV system, will generate approximately 200 megawatt hours of electricity annually, providing up to 8 percent of the Forrestal complex’s energy during peak hours.

SunPower, a Silicon Valley-based manufacturer, designed and installed the system, which is comprised of 891 individual photovoltaic modules, each with an efficiency of 18.5 percent, among the highest efficiency modules available.

The DOE’s investment in the array indicates its confidence in solar technology, Julie Blunden, vice president of public policy and corporate communications for SunPower, told EcoHome Online.

“The Department of Energy has been behind R&D funding for photovoltaics for decades,” she said. “They fully understand where we are in the curve of bringing solar to market. We have the Department of Energy, who is as knowledgeable as anyone about solar, and they’re saying, ‘Now’s the time.’”

The solar array, designed and installed by San Jose-based SunPower, is comprised of 891 individual photovoltaic modules, each with an efficiency of 18.5 percent, among the highest efficiency modules available.

The solar array, designed and installed by San Jose-based SunPower, is comprised of 891 individual photovoltaic modules, each with an efficiency of 18.5 percent, among the highest efficiency modules available.

Credit: Jeffrey Lee

The installation was one step toward meeting President George Bush’s executive order calling for all federal agencies to reduce their buildings’ energy intensity, or consumption per square foot, by 30 percent, and the Energy Policy Act’s requirement of having 7.5 percent of the DOE’s electricity provided by renewable energy by 2013.

“I determined that the Department of Energy should—and would—lead by example,” Bodman said. “America’s transition to a clean energy future begins with many small steps like this array because we have reached the point where energy savings accrue to our overall benefit. The U.S. economy’s most available source of new energy is the energy we lose everyday to waste and inefficiency.”

In a telephone interview, Blunden said that improved tax incentives for residential applications would increase national uptake beyond its traditional stronghold in California and called for a 30 percent residential tax credit that matches the business tax credit.

“In order for us to have nationwide solar, we really need the federal government to step forward,” she said.

The DOE solar installation also will serve as a demonstration project for the public and other federal agencies. A video display in the Forrestal lobby monitors electricity generated by the solar array and explains other aspects of the project. Furthermore, the rooftop installation includes a technology showcase area for monitoring and evaluating current and cutting-edge solar energy technologies.