Storage is essential for clean energy systems because communities need to maintain access to electricity even when the sun isn’t at its brightest or the wind isn’t at its strongest — and that usually means giving them a way to hold onto excess energy.
Traditional power systems are equipped to store energy before it’s been converted into electrical energy for the grid — such as in the form of fuel before it is used, as a Forbes article explains. Such systems help utilities create electricity to meet demand. Yet they can’t easily adapt to storing solar and wind power because these energy sources may generate more than the grid demands at a certain time.
Sage Geosystems is testing new ways of storing excess energy. The geothermal energy company built a 3,200-foot vertical reservoir to store water beneath the earth last year, according to Canary Media. Opening a valve at the top of the reservoir causes the pressure within to release, prompting the water to shoot upward so powerfully that it can turn a turbine to generate electricity.
This system, which has been likened to an “earthen battery,” will allow clean energy systems to store excess energy underground so they can maintain reserve power.
The process is actually pretty simple when you break it down. When a solar array or a wind farm generates extra energy, it uses that extra energy to pump the water into the underground reservoir so that when the time comes, that underground water can be used to generate more electricity on demand.
The first tests showed that 5,000 barrels of water in the reservoir could generate 200 kilowatts of power in just five hours. Meanwhile, 10,000 barrels could produce 200 kilowatts for nine hours, and 20,000 barrels can generate 650 kilowatts for two hours, according to Canary Media.
“The results that we’re getting are so good that we’re wanting to quickly move to a full commercial demonstration,” Sage Geosystems CEO Cindy Taff told Canary Media.
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