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Here’s a Building That Makes Money Selling Electricity

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Sipéa builds and runs social housing in Poitiers, central France. The buildings are very green, so much s that their use of energy is actually net-negative. In this way the building actually earns a little income from selling its excess power from the solar roof. This little extra comes in handy when when you are running a non-profit.

This new building houses Sipea headquarters. It was designed so that…

the operating cost would be negative : the selling to the grid of the electricity produced by the solar roof incorporated into the south-facing side on the roof more than offsets the running costs of the buildings energy use for heating and cooling.

The  rooftop solar produces 9,000 kilowatt-hours a year of electricity, and manages to use far less than that itself.

Due to PassivHaus construction (basically; lots of insulation)  the heating and cooling requirements of the building are negligible, thanks to careful design and construction. The roof is a kind of see-through solar that is not yet available in the US. Then it is sandwhiched between layers of glass to be super energy efficient: not lose heat or gain it.

The roof does let natural lighting in though, affording a dappled protection against direct solar glare, while reducing the heat loss and producing electricity. The cells are spaced out between two sheets of glass, mounted in between the double-glazed sun-roof.

The yearly operation of the building requires very little active heating, thanks to PassivHaus  insulation (22 cm of cellulosic wool in the outer walls) and it needs no active cooling at all, just ventilation.

Even with this highly efficient design, the  construction costs were only $207 a square foot and the yearly operating costs are lower than their previous – much smaller headquarters.

Images: Flikr user paspog
Source: Sipea
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