When I was in school for power systems planning the the accepted notion was that pumped hydro storage is cool and great, but like hydropower, it is extremely geographically dependent, and we have basically developed all of the places where it would work (at least in the US), or at least, by order of magnitude, there are not enough remaining untapped hydro-related resources to make a dent in projected storage demand. Is that a wrong understanding?
It is ridiculously uneconomical to create the volume for pumped storage. For context, with 100 meters of pressure head, you'd need 25,000 olympic swimming pools worth of water to store 12 hours of electricity from a 1 GW electric plant with 70% roundtrip efficiency. At a cost of $216/cubic yard of excavation, that's over $17 Billion. If you can make 3 cents per kwh profit buying at low times and selling at high, it would take 129 years to cover just the costs of digging the hole at the high spot. Then you need to dig another hole of the same size at the low spot so you can reuse the water.
There are really only 3 options - dam up a watershed so you can get a huge volume without much structure, build your resevoir on top of a mountain so you can get much larger pressure head and thus require less volume, or reuse a hole you were digging anyways such as an open pit mine. In all three cases you are heavily constrained by geography.
I think you'll find the attached link is project currently in development that does exactly what you're saying is economically impossible. It clearly is not impossible to build a relatively shallow dikes on top of a butte.
Usually the rock is waste from excavation. When buying it you pay the cost of transport, group that did the excavation might have even paid for the rock to be removed.
> All pumped storage requires is a big high spot and a big low spot
I think that's what the GP meant by "extremely geographically dependent." Finding a 1,000 ft height difference (using the Gordon Butte Project as an example) between reservoirs will be really challenging in huge swaths of the United States and elsewhere.
Doesn't need to be near population center. The majority of the energy I've used in my life comes from a dam over a thousand kilometres from where I live.
Yes, and add you can see it's already been developed - for over 60 years. That's not to say more can't be developed, but the rate of new development has been pretty low, and the prevailing belief was that this was the result of all of the best resources being used up.
...and even then they built it mostly inside the mountain, next to an old slate quarry. Which is going to help national park acceptability but not the unit cost of construction I suspect.
The question is, is this something that has been re-evaluated? Are there more site locations available than previously thought? Have the economics changed significantly? Was this a known-wrong assumption 15 years ago? Has the public perception changed re: the environmental costs vs benefits of this land use?
I would much rather we build a bunch of pumped hydro than a bunch of chemical batteries, on the belief that it is a much more sustainable technology. But I have seen a lot of online discussion about pumped hydro that treat siting, operational, economic, and land use concerns as if they don't exist, when often they are the primary reasons these projects don't get built.
It is not "more sustainable". It is just, likely, cheaper.
Siting, operational, and land use concerns for pumped hydro are, generally, trivial. If one site is bad, another is good. There is absolutely no shortage of sites, so only the best need be even considered.
