Alternative Energy

Twenty student teams from universities in the U.S., Puerto Rico, Germany, and Spain arrived in Washington, D.C., for the third Solar Decathlon, sponsored by the energy industry and the Department of Energy and held Oct. 12-20 on the National Mall. The student teams assembled real-life, 800-sq-foot, super-efficient homes. All were completely sun-powered, with sufficient energy to light, heat, and cool the home; run a full kitchen; and charge a small electric vehicle.

Like athletes in an Olympic track and field decathlon, the teams competed in 10 categories. Seven categories focused on energy use, and others included comfort and marketability. Each team received $100,000 from event sponsors, about half of what they needed for the competition. Home designs relied strongly on passive heat and efficiency to cut electricity demand.

Carnegie Mellon University's home (far right) incorporated a living wall and roof-a "greenscape" of plants to help cool the house in Washington's heat. The University of Cincinnati relied on another wall, one with 120 tubular thermal collectors to meet other household heating and cooling needs. All homes used solar cells and batteries to meet energy demands. Underscoring the event's importance, DOE says some 70% of U.S. electricity is used to operate buildings.