• ceiphas@lemmy.world
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    2 days ago

    you know that grid storage does not always mean “a huge battery”, you can also just pump water in a higher basin oder push carts up a hill and release the potential energy when you need it…

    • iii@mander.xyz
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      2 days ago

      Pumped storage is a thing yeah. But might just as well go full hydro, if you’re doing the engineering anyways.

      • wolframhydroxide@sh.itjust.works
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        2 days ago

        I feel like we’re missing the part about “push carts up a hill”, which involves virtually no serious engineering difficulties aside from “which hill” and “let’s make sure the tracks run smoothly”. See: the ARES project in Nevada

        • iii@mander.xyz
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          2 days ago

          Yeah, that’s 50MW, storing power for 15 minutes, so 20MWh. (1).

          There’s also a similar company: gravicity.

          They’re a fun academic endeavour. But if gravity provides the potential, water beats them per dollar spend. It’s not even close.

          So do regular batteries.

          • wolframhydroxide@sh.itjust.works
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            2 days ago

            A fair point, but given how the best places to build solar infrastructure tend to not have easily accessible large volumes of water, I should think that economies of scale can apply if we were to put actual investment into scaling up the gravitational potential. Sure, it’s not a geometric law like for kinetic energy, but greater height and greater mass are both trivial quantities to scale in places with large empty areas. I’m simply pointing out that we’ve never invested in that obvious possibility as a civilization. Am I missing something obvious that makes the scaling non-viable?

            • iii@mander.xyz
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              2 days ago

              Transportation of electrical power is quite efficient. I think that colocation of generation amd storage are economically rarely a technical necessity.

              I can see it work in terms of national security, but then again, regular li-ion have better economics.

              The biggest problem with gravitational potential is P=mgh, that is, potential energy only grows linearly in mass and height.

              • wolframhydroxide@sh.itjust.works
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                2 days ago

                I agree with you on the linearity issue. I just feel like using its size as a criticism is invalid, given that the very source you cited pointed out that the reason it’s so small is because they chose to reuse an already-disturbed site, rather than building it on 100 acres of BLM land, which I’d argue is quite admirable. The colocation point is also fair, though our water resources in the entire american west are severely limited, and will become moreso over the next 50 years. Utah’s declining snowpack and the overdrawn Colorado can only cover so much. I feel like, while the GPE law is linear for both mass and height, the fact that we can scale both is a point in favor of both pumped hydro and rail storage, and rail storage can be stored virtually indefinitely, as long as it doesn’t have time to rust in place. Being able to supplement the off-hours is absolutely doable with rail.

                • iii@mander.xyz
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                  1 day ago

                  In practice, you’re usually using existing geography (historical or geographical) for height. So you’re left with scaling m.

                  I honestly also hoped it would be a great idea. I donated to gravicity back in the day. You live and learn.

                  • wolframhydroxide@sh.itjust.works
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                    1 day ago

                    Again, a fair point. Assuming that anyone with an idea of the meaning of “potential energy” survives the next ten years, I’d still like to see it more fully explored in the american west, but it is, unfortunately, rather a moot point for at least five years.