The Department of Energy (DOE) and Department of Defense (DOD) have dedicated the largest alternating current (ac) photovoltaic (PV) system in the United States, serving the largest office building in the world: the Pentagon.

The system was assembled and connected to the Pentagon in seven days, the first step in a real-world test to confirm that the SunSine™ 300 modules are as reliable and easy to install as planned during their research and development.

Energy initiative

Installing this solar power system is a step toward meeting President Clinton’s goal to make the federal government as energy efficient as possible, as stated in the recently issued Executive Order 13123 and as part of his Million Solar Roofs Initiative.

This initiative seeks to add solar power systems to one million buildings across the country by 2010.

Secretary of Energy Bill Richardson said, “DOD is stepping out decisively as a leader with this project, and with the hundreds of Million Solar Roof installations they have already installed.”

Solar fits into Pentagon's plans

The SunSine modules are different from typical PV panels because each unit has its own microinverter that converts the direct current produced by the PV material, to alternating current that can be used by homes or office buildings.

The new system was installed in the midst of a massive renovation of the Pentagon. Scheduled to take 10 years, renovating the 50-year-old building will cost $1.1 billion.

The solar panels are part of an effort to increase the energy performance of the facility, with a goal of saving 25% in building energy costs. Other energy-efficiency projects include upgrading lighting systems and retrofitting of the windows.

The PV system has a maximum output of 18 kW, equal to the electric capacity of three single-family homes. By harnessing the power of sunlight, greenhouse gas emissions will also be curtailed.

Ascension Technology, a division of Applied Power Co., Lacey, WA, built the panels. DOE and more than 20 electric power companies supported the development of the modules, which are National Electrical Code-compliant and are the world’s first UL-certified ac modules.

Adapted from FEMP Focus, September/October 1999, published by the U.S. Department of Energy, Federal Energy Management Program, Washington, DC.