A cheap way to store wind and solar power
Invention consists in two large containers of gas and gravel, one hot (500C) and one cold (–160C) provide the temperature difference to operate a heat pump.
The surplus of wind power or solar energy is used to heat up the contents of the hot tank and to retain that temperature.
According to the company’s chief technology officer, it could be cheap at utility-scale – as little as $10/kWh.
The overall operating efficiency of the energy storage process is claimed to be 72% to 80%.
The containers are large and for this much energy storage each tank of gas and gravel is the size of a small building.
California is looking for energy storage because 33% from the electricity will come from renewable sources by 2020.
Also, the world will need more such storage devices because renewable energy is booming.
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