"I want to congratulate this year's Solar Decathlon champion, Technische Universitaet Darmstadt, and the 19 other teams for their innovative designs and application of solar technologies," US Energy Secretary Samuel Bodman said at the awards ceremony in Washington, where the decathlon began last week.
Teams from universities in Canada, Germany, Puerto Rico, Spain and the United States took part in the competition, which, like the sports version of the decathlon, consists of 10 categories.
"It was a close race with the University of Maryland, which also built a beautiful house, with very good architecture and a good system," Barbara Gehrung, the German team's spokeswoman, told AFP.
Teams in the competition erected their energy-efficient homes, powered exclusively by the sun, on the National Mall in Washington, in the shadow of the White House.
The homes were open to the public for the duration of the competition.
They were judged on whether they maintained a comfortable temperature, had adequate lighting, sufficient power for household appliances and home electronics, and hot water -- all produced using solar energy.
The houses also had to power an electric vehicle.
"We'll keep from this experience the fact that solar energy works," Gehrung said.
"We have proved that we can live better in the future without fossil fuels. We can, if we work together internationally, achieve something."
The most points in the competition were awarded for architecture (200 points), followed by engineering and market viability, which measures the market appeal and suitability to daily living of the house, at 150 points each.
The remaining categories -- communications, comfort zone, appliances, hot water, lighting, energy balance and "getting around", which has to do with the electric car -- scored a maximum 100 points each.
The Darmstadt team reaped the highest score for architecture, engineering, and energy balance.
The next Solar Decathlon will take place in 2009.