The electricity grid is increasingly using solar and wind power. Depending on those two sources requires the ability to store energy to have on hand when the sun isn’t shining and the wind isn’t blowing. Energy needs to be stored away to be used hours, days, or even weeks after it is produced.
Energy storage is booming. California has increased its energy storage capacity tenfold in recent times. One day in April, storage batteries were the largest source of electricity in the state for a period of two hours. But batteries are not the only way to store energy. There are chemical, electrochemical, mechanical, and thermal methods that each has potential advantages and unique features.
A project in Kern County, California, is making use of an abandoned oil field to create a long-term energy storage installation. The plan is to retrofit depleted oil wells to store concentrated solar energy in superheated groundwater for long periods of time. The stored heat can then be used to drive turbines when electricity is needed.
Some 1,200 feet below the surface of the oil field are pockets of permeable sandstone that have been emptied of the oil they previously contained. An array of parabolic mirrors will gather solar energy that will heat silicon oil in an underground loop to 700 degrees Fahrenheit. The oil pipeline will heat up groundwater down below. When electricity is needed, the heated groundwater will be brought to the surface to operate turbines.
There is no new technology involved. The individual aspects have never all been combined before, but the likelihood of success is high. There are lots of depleted oil fields that could be used this way in the future.
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Can a California Oilfield Be Retrofitted to Store Solar Energy?
Photo, posted July 18, 2017, courtesy of John Ciccarelli / BLM via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio