The Solar Decathlon is an international competition run by the U. S. Department of Energy. The aim is to build a Zero Energy Home, which produces as much energy from renewable sources, as it consumes. Just like the Olympic decathlon this competition consists of 10 contests that center on all of the ways in which we use energy in our daily lives. The 10 contests are: Architecture, Market Viability, Engineering, Lighting design, Communications, Comfort Zone, Hot Water, Appliances, Home Entertainment and Net Metering. 20 teams of college and university students participate in the Solar Decathlon 2009, among them one team from Germany from Darmstadt University of Technology.