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Another myth is that hydroelectric is “green.” It’s absolutely not. The huge amount of land required to build something like the hoover dam or the three-gorges dam is massively destructive to the existing ecology. It’s often overlooked, but land use has to be part of any environmentally sound analysis.

I would say that while the Hoover Dam, or the Three-gorges dam by themselves are acceptable, they are wholly impossible solutions for grid level storage for the entire united states/China. How practical do you think it would be to build thousands of hoover dams?

Other options like kinetic batteries etc, all come down to energy density. The highest energy density options that humans can harness are nuclear Isotopes like Uranium 238, or Plutonium 239 (what powers the voyager probes) After that is lithium batteries at ~<1% density of a nuclear battery. Everything else is fractions of a percent as efficient. Sure there are some specific use cases where a huge fly-wheel makes sense to build (data centers for example) but those cases are highly specific, and cannot be scaled out to “grid-level.” The amount of resources required per kilowatt is way too high, and you’d be better off just building some more power-plants.

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frezik@lemmy.blahaj.zone ⁨3⁩ ⁨hours⁩ ago
This is why you have HVDC lines.

The longest one is in Brazil, and is about 2400km long. With that kind of reach, solar in Arizona can power Chicago, wind in Nebraska can power New York, and every single existing hydro dam along the way can provide storage.

These problems are solved. We do not need new nuclear.

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trailee@sh.itjust.works ⁨9⁩ ⁨hours⁩ ago
Unclear if you’re misinformed or disingenuous.

Hoover Dam does generate power, but it’s not an energy storage project to time-shift intermittent clean energy generation to match grid consumption. That’s known as pumped hydroelectric energy storage, and it requires having paired reservoirs in close geographic proximity with a substantial elevation difference. It’s not an ideal technology for several reasons, but it’s the largest type of grid-scale storage currently deployed. Fundamentally it’s gravitational potential energy storage using water as the transport medium.

A higher-efficiency but not yet fully proven technology also uses gravity and elevation differences, but relies on train rails and massive cars. Here’s one company leading the charge, as it were.

Nuclear isn’t a good option to balance out the variability of wind and solar because it’s slow to ramp up and down. Nuclear is much better suited to baseline generation.

There are plenty of other wacky energy suave ideas out there, such as pumping compressed air into depleted natural gas mines, and letting it drive turbines on its way back out. That might also be riddled with problems, but it’s disingenuous to claim that chemical energy storage is the only (non-) option and therefore increasing wind and solar necessarily also increase fossil fuel scaling.

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- PowerCrazy@lemmy.ml ⁨8⁩ ⁨hours⁩ ago
  Again, i’m talking energy density. All those other wacky ideas aren’t viable at all. Yes I know that the hoover dam is for generation, but the idea of pumped reserve power is literally identical to hydroelectric generation. The only difference is we would have a man-made solar/wind powered pump fill the resevoir, instead a natural source of solar power fill the resevoir. Either way, it’s a huge amount of land use for it to be considered “green.”
  
  Additionally I never claimed nuclear power should be used as a peak generation, it should 100% used for baseload replacing all of our fossil fuel reactors, with huge taxes being applied to carbon generators.
  
  As an aside:
  
  A higher-efficiency but not yet fully proven technology also uses gravity and elevation differences, but relies on train rails and massive cars. Here’s one company leading the charge, as it were.
  
  This idea is trash and as far as I can tell the hypothetical existence of this is an oil industry fud campaign. The only viable version of this is pumped hydro, which has the land use problem I’ve already described.
  
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  - trailee@sh.itjust.works ⁨8⁩ ⁨hours⁩ ago
    Pumped hydroelectric storage obviously works with the same kind of turbines as dams located on rivers, but the land use is far from “literally identical”. For one, I agree with you that damming rivers is generally a bad thing. Large dam sites are chosen to min-max construction effort and reservoir capacity, and usually double as flood control. A grid storage project only needs to hold enough water for its daily power use, and it doesn’t need to be located directly on a water course. That’s not to say that there are unlimited suitable sites, but it’s more flexible.
    
    Pumped hydro storage is quite green in its lack of carbon emissions and ability to time-shift green generation capacity to match grid demand timing. Land use is a consideration, but large anything requires land. You haven’t actually attacked the weakest part of pumped hydro, which is that there just aren’t very many geographically suitable locations for it.
    
    You’ve also neglected to acknowledge the pesky spent nuclear fuel storage problem, which is unsolved and distinctly not eco-friendly. There are potentially better paths available such as the thorium fuel cycle, but they all either have no economic traction or are actively opposed by various governments (which don’t have any good solutions for existing spent fuel).
    
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