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Germany Overturns Solar Rules to Win Decathlon With 200% Solar Home

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For the first time in the Solar Decathlon, a home that has produced twice the amount of energy as it used, won the first prize. And it did so in a very unusual way.

Every year the US Department of Energy has a solar competition for the best house that gets 100% of its electricity from  solar panels. Most are content to supply  100% of their electricity from solar, by simply covering the roof with solar panels.

Germany’s entry; the two story Cube House was unique in that the entire house is covered by solar panels, something that most solar installers would not recommend, because walls are at the wrong angle to the sun.

Walls are at 90 degrees, not the 20 or so which is the optimal angle for solar panels.

The 11 kW solar panel system was comprised of 40 solar panels (monocrystalline silicon) for the roof with 250 thin-film (copper indium gallium diselenide) panels for the walls.

These panels flipped out are at about70 degrees. At this angle they produce less power from the same panels, but a little more than if they were straight up the wall at 90 degrees. On a North facing wall this can be as low as 50%.

In addition,  thinfilm is itself a less efficient solar producer, although better at ambient light conversion -  so they were a better choice for this maverick wall solar idea than PV.

Bucking the common wisdom is nothing new for Germany. That  is how that nation, with as little sun as Massachusetts, somehow leads the world in solar roofs. The government there simply pays people to make solar power with a Feed in Tariff, requiring electric utilities to buy from anyone who sends power to the grid, from their roof, or their field. So people do.

So it is interesting to see how successful breaking the rules of common wisdom can be.

Image:  Solar Decathlon
Source: Energy Matters