I’ve posted on this subject before. We’re still not particularly good at storing electrical power but we’re actually pretty good at storing heat. That presents a potential strategy for storing the power that would otherwise be wasted from wind and solar and, as this article at Bloomberg notes, companies like Google are trying to make use of it:
Two tanks are filled with salt, and two are filled with antifreeze or a hydrocarbon liquid. The system takes in energy in the form of electricity and turns it into separate streams of hot and cold air. The hot air heats up the salt, while the cold air cools the antifreeze, a bit like a refrigerator. The jet engine part: Flip a switch and the process reverses. Hot and cold air rush toward each other, creating powerful gusts that spin a turbine and spit out electricity when the grid needs it. Salt maintains its temperature well, so the system can store energy for many hours, and even days, depending on how much you insulate the tanks.
Scientists have already proven this as a plausible storage technique. Malta’s contribution was to design a system that operates at lower temperatures so it doesn’t require specialized, expensive ceramics and steels. “The thermodynamic physics are well-known to anyone who studied it enough in college,” Green said. “The trick is doing it at the right temperatures, with cheap materials. That is super compelling.”
The real challenge is making the process practical and that’s what they’re trying to master now.
