Team Germany's window louvers with integrated thin-film CIGS cells. (Credit: Stefano Paltera/DOE Solar Decathlon)

Team Germany!

Team Germany won first place in the 2009 Solar Decathlon by applying photovoltaics to every available surface. I had been rooting for Virginia Tech for their use of aerogel as insulation that allowed natural light to shine through, but it only ranked 13 out of 20 competitors.

Team Germany’s Cube House was considered the most technologically advanced.

On the roof: a 11.1 kW photovoltaic system of 40 monocrystalline silicon panels. On the sides: 250 thin-film panels that look like glossy clapboards. The thin films used copper-indium-gallium-diselenide layers.

The combination system was expected to produce 200 percent of the energy needed by the house. The thin film panels, while less efficient than conventional silicon, were projected to perform better in cloudy weather than silicon.

Team Germany got its proof on the competition’s fifth day when skies turned slate gray and a cold rain splattered the solar village. By late afternoon, as federal commuters started streaming home and electricity demand throughout the city began climbing, the Team Germany house was producing 12.68 kW and consuming 12.33 kW, for a net export of .35 kW. Net production also occurred on two other rainy days.

Team Illinois’ house finished a close second, emphasizing energy efficiency over power production.

“Team Germany built a gingerbread house packed with solar panels,” said Richard King, DOE Solar Decathlon director. “In the rain, the thin-film panels were making electricity. It made the difference.”

Each team actually was graded on 10 criteria:

  • Architecture
  • Market Viability
  • Engineering
  • Lighting Design
  • Communications
  • Comfort Zone
  • Hot Water
  • Appliances
  • Home Entertainment
  • Net Metering

Team Germany was the only team to score a perfect 150 points out of a possible 150 in the net metering category, for having produced more electricity over the entire two-week testing period than it consumed. The DOE gave the Net Metering the highest weight in the contest, and each of the other categories received 75-100 possible points each.

The University of Minnesota entry was winner in the Engineering category and ranked 5th overall.