A grid with a larger proportion of wind and solar requires more storage capacity to overcome intermittency. Energy is stored all around us, in all sorts of ways. But energy storage is most useful when it is predictable, convenient, and dense, packing lots of power into a small space. Today’s Li-ion batteries are low-density by comparison, and renewable-storage systems also struggle to achieve density, convenience, and scale. The basic technology behind compressed-air energy storage goes back decades, and can involve pumping air into underground caverns, natural or artificial, then letting it out again. There’s room for many kinds of solutions in the clean grid to come; at the same time, the landscape is hyper-competitive. Just as one can store potential energy by lifting a block in the air, you can store it thermally, by heating things up. Companies are banking heat in molten salt, volcanic rocks, and other materials. Giant batteries, based on renewable chemical processes, are also workable. It’s possible to envision a future in which some of the technology works out, and the globe is reshaped by a combination of renewable energy and renewable storage.
By Matthew Hutson. The New Yorker. April 18, 2022.
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