Solar Settlement, Freiburg

Rolf Disch's Solar Settlement (Solarsiedlung) in Freiburg, Germany, completed in 2006, was the world's first residential development where every home produces more energy than it consumes — a "PlusEnergy" standard now adopted worldwide. The 59 terrace houses, each featuring a "sunship" roof of solar panels angled toward the south, collectively generate 600,000 kilowatt-hours of surplus electricity per year.