A giant ‘water battery’ in the Swiss Alps is finally operational, 14 years after construction work began. The Nant de Drance hydroelectric plant can collect enough energy to charge 400,000 car batteries.
Until fusion can solve all our energy needs, we have a renewable energy problem to solve. What do we do when more energy is produced than we need?
On particularly windy or sunny days, production from wind and solar farms can exceed the respective electricity demand. While this is obviously a better problem than the other way around, and sometimes even leads to a situation where consumers are paid to consume electricity, storage solutions are needed for days when the sun doesn’t shine and the wind is calm , appropriate IFLScience.
Why a “water battery”?
The Nant de Drance hydroelectric plant is a new solution for storing large amounts of this excess energy. At times when renewable energy sources produce more energy than demand, the surplus energy is used to pump water from the plant into the Vieux Emosson reservoir above. The water can then be used by the hydroelectric plant below when more power is needed, using the water to power the turbines as it flows through it at 360 cubic meters per second.
The idea has been called a “water battery”, in the sense that the energy is “stored” in the form of water, only at a slightly higher altitude than it was previously. While its efficiency isn’t perfect, it’s much, much better than letting excess energy go to waste.
“There are losses as in any warehouse, but the yield is very good. We have a yield of approximately 80% throughout the cycle,” said director Alain Sauthier.
The hydroelectric plant can store enough energy for a large part of Europe
“In less than ten minutes we can reverse the direction of rotation of the turbines and switch from energy production to storage. Such flexibility is essential to react promptly to the needs of the power grid and to adapt the production and consumption of electricity. Otherwise, there is a risk of a collapse of the network and a blackout,” said director Alain Sauthier.
The plant can provide storage for much of Europe, not just Switzerland. Now fully operational, this is one of the most powerful plants on the continent.