For 10 days next October, the National Mall in Washington will be dotted with solar-powered homes designed by 20 teams of college and university students from around the world. A project of the US Department of Energy and the National Renewable Energy Lab, the Solar Decathlon takes place every two years and is a showcase for designing, building and operating homes that are completely powered by the sun. In 2009, the event, which is free and open to the public, will be held Oct. 9-18. House tours will be given daily except Wednesday, Oct. 14, when they will be closed for judging.The University of Missouri-Rolla demonstrated one of 20 solar homes set up on the National Mall in Washington in the fall of 2007. The home featured an evacuated tube solar thermal system to heat water for cooking, bathing and washing. Photo credit: Kaye Evans-Lutterodt/Solar Decathlon.According to Richard King, director of the Solar Decathlon, the big surprise in 2007 was that the German team, after traveling across the ocean with a house in tow, competed on American soil against 17 US universities to win the competition. According to King, “The University of Darmstadt designed an exquisite house with cleverness and detailed engineering. They were a surprising delight.” He added that the smallest university from the farthest land distance, Santa Clara University in California, won third place. Everyone thought that they would never even make it, especially when their axel broke on the transport truck in Nebraska, and it took three days to get it fixed. King recalled that, “As they limped into Washington three days late, we all counted them out. Early in the contest when they started in 18th place, no one gave them any hope – except the resilient team of students. They worked hard and clawed their way up in the standings throughout the contest and surprised everyone when they captured third place.”The teams, which actually build their homes on the National Mall, participate in 10 different contests. Each team selected to participate in the Solar Decathlon is awarded $100,000, which helps to advance research on reducing the cost of solar-powered homes. The team then has to raise $200,000 to $300,000 to pay for its home and for transporting it to Washington.The Solar Decathlon was inaugurated in 2002 and also was held in 2005 and 2007. One of the event’s goals is demonstrating “zero energy homes,” which use renewable resources to produce all the energy they consume.