To make sure people always have access to electricity, power plants are making power regardless of actual consumption, so there is discrepancy between supply and demand which worsens at night. Since wind power runs primarily at night, a lot of electricity is wasted if it is not stored.
One of the most widely used methods to store electricity are batteries. Market leaders are investing millions in building gigafactories. For example, the second factory for lithium-ion batteries is built with an investment of 500 million euros by Daimler subsidiary Accumotive in Kamenz. Tesla Inc. has plans to invest in and build 10-20 gigafactories worldwide in the future. The company has invested 600+ million USD in its plant in Nevada to produce mass quantities of lithium-ion batteries.
Yet, some companies have a different strategy using salt caverns to store large amounts of surplus energy, like one Alabama power company is using “Half a mile underground, a salt cavern that could fit the Statue of Liberty holds Power South Energy Cooperative’s most useful resource: air“.
The McIntosh Power Plant is the only utility-scale Compressed Air Energy Storage (CAES) facility in the United States, and one of the few in the world. (“This is the world’s second diabatic compressed air energy power plant, that began operations back in 1991. The world’s first compressed air energy storage power plant started operation in Huntorf approx. 40 km north-west of Bremen in 1978“)
Power South Energy Cooperative compresses air and stores it in a salt cavern to produce electricity when needed by the natural gas plant. Thanks to storage, it is able to compress the air at night when electricity is cheap and it can supply electricity to 110,000 homes for 26 hours. Although the plant does not use renewable sources of energy at the moment, this method can use “green” sources of electricity for compression.
There is a plan for such facility – The Bethel Energy Center in West Texas. If developed, it would be a salt CAES plant that uses electricity produced by wind turbines to compress the air /Anticipated Commercial Operation Date: Summer 2020/. Energy storage not only facilitates the integration of renewables, but it also reduces the amount of gas needed.
Image credit: inhabitat.com – New York Times