Why pumping water back into hydro dams beats batteries for renewable power

To cut U.S. greenhouse gas emissions in half within a decade, the Biden administration’s goal, the U.S. is going to need a lot more solar and wind power generation, and lots of cheap energy storage.Wind and solar power vary over the course of a day, so energy storage is essential to provide a continuous flow of electricity. But today’s batteries are typically quite small and store enough energy for only a few hours of electricity. To rely more on wind and solar power, the U.S. will need more overnight and longer-term storage as well.While battery innovations get a lot of attention, there’s a simple, proven long-term storage technique that’s been used in the U.S. since the 1920s.It’s called pumped hydro energy storage. It involves pumping water uphill from one reservoir to another at a higher elevation for storage, then, when power is needed, releasing the water to flow…

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