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Your link says that at best we could double our current hydro generation capacity, which supports my point: it's simply too little for our storage needs, and if

by xyzzyz 6y ago

Your link says that at best we could double our current hydro generation capacity, which supports my point: it's simply too little for our storage needs, and if we electrify more of our economy (i.e. use it to replace heat and transport for which we use a lot of fossils now), it will be even less. It might still be worth doing, but is far from solving the storage problem: it just has significant limits on its potential scale.

nl 6y ago
> Your link says that at best we could double our current hydro generation capacity No, it says "that without building a single new dam" [hydro could roughly double its existing capacity in the US]. I'll assume you just misread that, but in any case that's pretty different to building new dams, or utilising tech like mines, or at-sea pumped storage.
- xyzzyz 6y ago
  > No, it says "that without building a single new dam" [hydro could roughly double its existing capacity in the US]. No, that's not what it says. It says: > The report estimates that without building a single new dam, these available hydropower resources, if fully developed, could provide an electrical generating capacity of more than 12 gigawatts (GW), equivalent to roughly 15 percent of current U.S. hydropower capacity. Without constructing any new dams, you only increase it by 15%, not double it. Also, consider that 12 GW is 105 TWh per year. US consumes 4100 TWh of electricity per year. It would sure be nice to increase non-fossil electricity production by 2.5%, but that's clearly not very much. If the plan is to use hydro to cover the shortfall when the renewables are not producing enough, you need much more generating capacity than 12 GW, and more than 65 GW your link suggests could be potentially built. Finally, 2.5% is on the order of our annual growth in electricity consumption, which will in fact accelerate as we move off fossils. Thus, building out all possible hydro will only buy one year of growth in consumption.
  - nl 6y ago
    Yes, sorry you are right! My error was confusing the "7% total capacity" and "15% existing capacity" not being off the same baseline.

by xyzzyz 6y ago

nl 6y ago

> Your link says that at best we could double our current hydro generation capacity No, it says "that without building a single new dam" [hydro could roughly double its existing capacity in the US]. I'll assume you just misread that, but in any case that's pretty different to building new dams, or utilising tech like mines, or at-sea pumped storage.

xyzzyz 6y ago
> No, it says "that without building a single new dam" [hydro could roughly double its existing capacity in the US]. No, that's not what it says. It says: > The report estimates that without building a single new dam, these available hydropower resources, if fully developed, could provide an electrical generating capacity of more than 12 gigawatts (GW), equivalent to roughly 15 percent of current U.S. hydropower capacity. Without constructing any new dams, you only increase it by 15%, not double it. Also, consider that 12 GW is 105 TWh per year. US consumes 4100 TWh of electricity per year. It would sure be nice to increase non-fossil electricity production by 2.5%, but that's clearly not very much. If the plan is to use hydro to cover the shortfall when the renewables are not producing enough, you need much more generating capacity than 12 GW, and more than 65 GW your link suggests could be potentially built. Finally, 2.5% is on the order of our annual growth in electricity consumption, which will in fact accelerate as we move off fossils. Thus, building out all possible hydro will only buy one year of growth in consumption.
- nl 6y ago
  Yes, sorry you are right! My error was confusing the "7% total capacity" and "15% existing capacity" not being off the same baseline.