Yes, we can do this for some dams, but not enough to move the needle. Hoover Dam’s generating power is quite tiny relative to the total storage needs, and if yo

Yes, we can do this for some dams, but not enough to move the needle. Hoover Dam’s generating power is quite tiny relative to the total storage needs, and if you add up all the other viable dams, you’ll find that it doesn’t add up to a lot. To put it in context: Columbia River basin produces 40% of US hydroelectricity. Out of 14 dams on Columbia River, 12 of them produce (each individually) more electricity than Hoover Dam, most by a factor of 3x or more. Very little of it can be turned into storage as of today, what does not get used must be spilled. This is not to say that using dams for energy storage is a bad idea, it’s not. It just will not work well in practice with most of currently existing dams, at least without huge retrofits and/or screwing over downstream water consumers and upstream reservoir users.