this post was submitted on 16 Nov 2023
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Doesn’t pumped hydro storage require natural variation in elevation?
some projects use old mines for this
I don't want to sound pedantic, but how exactly do you believe pumped storage work? It's not that complicated: you have a dam, i.e. renewable hydro, and when you get excess electricity from elsewhere, some of the water downstream is pumped back upstream so the dam can do its thing once again. Essentially, developing hydro storage means developing hydroelectricity and dams, but if hydro's contribution to the grid hasn't increased much in a very long time, it's not because of conspiracies, but simply because most of the available capacity has been tapped already: https://en.wikipedia.org/wiki/Hydroelectric_power_in_the_United_States
So, back to our initial problem: chemical storage (batteries) is expensive, environmentally dubious, problematic in many aspects and inefficient, chemical conversion (e.g. hydrolysis) is wasteful/inefficient, etc. So, no, we have no good answer to that.
In technical terms, could you lay out what's the difference? You've got a water retention system that empties into a generator and a capability to pump some of the water back upstream. What larger storages and generators do we have besides dams? None, and there's no topographic feature that could be at an advantage there. Because the problem at hand is one of scale: https://ourworldindata.org/grapher/electricity-prod-source-stacked?country=~USA
Assuming that energy demand remains the same (instead of increasing, which we know will be the case with more electrification), and that, to keep targetting those 4000TWh produced, we replace coal and gas by wind and solar. That would mean having to store what amounts to 2000TWh of production (under an extremely optimistic assumption of 80% storage capacity for the replaced energy only). That would mean that, just to buffer out what solar+wind require in storage, we would have to surpass what current hydro produces, 8 times over.
I know this isn't accurate (storage ≠ production, grid can be balanced out geographically, etc), but we are one order of magnitude in trouble already.
I mean, you don't answer the billion dollar question here. Let's not call it a dam, but a container, and let's not mention the need to pump anything. The amount of (potential) energy you can store is a function of the volume of the above container, isn't it? Then, could you estimate the amount of water this container would need to be able to retain in a scenario where the grid relies primarily on intermittent energy sources? And can you propose an engineering solution to contain this much amount of water?
The intuition here is that you are re-inventing dams, without the room to build more.
I don't agree nor disagree with the rest of what you say, I just can't get beyond the "energy storage is a solved problem" point yet.
That's correct, those are Joules in SI. Now if you turn this mass into mass per second by introducing the flow of water through the dam, you get the power (Watts) produced through the release.
But here we are talking about energy storage (Watt.hours), which is, for how long will you be able to sustain emptying your container while delivering the desired power. And obviously this is a function of how large the container is because eventually you will run out of water no matter the elevation difference.
So, now that we are back 3 messages up thread
To help you out with the scale, again, your example from earlier (Bath county) has a storage capacity of only 24GWh, annual hydro production of the USA is 256TWh. Bath county has a reservoir of 34•10⁶m³, Oahe dam has 29•10⁹m³.
Anyway, this is a good tool to keep an eye on this "solved problem", and relate to how the world is dealing with it, independently from the regulatory dissatisfaction you mentioned: https://sandia.gov/ess-ssl/gesdb/public/
And this paper goes neatly through the variables at play and why oversimplifications are not helpful: https://www.frontiersin.org/articles/10.3389/fenvs.2023.1076830/full
why, in your opinion, is this more an obsession than "pulling power cables" and "tugging floating wind turbines"? This is very much part of the grid transitioning towards more intermittent (and renewable) energy sources. We can't just keep putting wind and sun without offsetting the intermittence (since we are also removing carbon-heavy sources), which means either adding low CO₂ base-load (nuclear), but we are not going there fast enough, or adding more storage (and neither there do we have a solution).
It's funny, because my link https://sandia.gov/ess-ssl/gesdb/public/ shows that there are 1693 such projects in the world, with 739 by the USA. China, with a more important landmass and not bothered by F35s (or whatever) doesn't even cross the 100 threshold. So the onus of the proof is on you to demonstrate that we can actually build hundred more pumped storages in the USA for it to make a difference.
This isn't even contentious. What is, is that you believe that we have this silver bullet of pumped hydro to cover our upcoming energy storage needs. And that's not nearly the case.
Which was my point all along
I don't want to argue about semantics. If the solution is too costly to be implemented, then it's not a solution. I don't think there's more to be said here.
Let's keep this simple. It all started with your affirmation that energy storage is a solved problem. When I asked how you would go about implementing the solution, you brought-up pumped hydro. And we ended-up with enough data pointing towards this problem being all but solved (cost is one aspect that you are quick to dismiss, but engineering/practicality is a major one).
In all, we agree, we are in the same boat, we want more budget being allocated for the energy transition. But where we diverge I that I don't see how turning a complex problem into a caricature (bordering a conspiracy theory) helps anyone. The physical world we live in doesn't care about opinions, and isn't affected by digital money. You don't have to believe a random stranger on the internet (who happens to work in this field), if this is your crusade, there should be people near you, academics, scientists, engineers, who would be pleased to educate you on the subject. This is pedant, I don't see where's the belligerence.