The Suitland Federal Center, five miles east of Washington, D.C., installed a photovoltaic (PV) system that was as part of President Clinton's "Million Solar Roofs" initiative. The General Services Administration (GSA) paid for the installation with help from the U.S. Department of Energy (DOE) through the Solar Electric Power Association TEAM-UP program.
The installation site was a former cooling pond (like a swimming pool, 7 ft. deep and 320 ft. in diameter) that had been filled with soil, then compacted and graded. A total of almost 2,300 linear ft. of photovoltaic array structure, divided into 80-ft. bays, had to fit into an area just slightly longer than a football field. To minimize self-shading, the rows were spaced 25 ft. apart. The 100 kW AC photovoltaic array will produce 480 V AC and up to 150 amperes. This power will be fed directly into the utility grid without storage. There is a modest financial payback of 30 years (sooner if energy prices rise faster than inflation), but using renewable clean energy and the knowledge gained from the project is beneficial.
Payback period: 30 years
Cost savings: $6,885/year (at $0.05/kWh)
Energy savings: 137,700 kWh/year