"As the world looks to incorporate more renewables into energy grids, centuries-old systems that can balance supply and demand are being reappraised and innovated upon."
"In late November, in a quiet corner of Devon, England, workers began adding a secret, light brown powder to water as they mixed up a special fluid that can store energy. They blended it with the utmost care, like some kind of giant protein shake, over the course of multiple weeks. Their goal was to achieve a mixture 2.5 times denser than water.
“It’s quite a hands-on process. At bigger scales, we would automate it,” says Stephen Crosher, chief executive and co-founder of RheEnergise, a British energy-storage company. He emphasizes that the mineral-based fluid must flow easily. “You want it to be really runny.”
That’s because, in the company’s demonstration system, at a china clay mine near the city of Plymouth, this mystery liquid can now slosh down angled pipes connecting an upper container to a lower container 80 meters below. In the process, the fluid drives turbines to create electricity. Pumping the mixture back up at times when there’s excess energy on the grid resets the whole system. It’s a new take on an old energy-storage technology currently experiencing a renaissance: pumped hydro."
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