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We do have a very simple large-scale storage system that's already in use across the world: pumping water uphill. It's just not as economical as rain when you f

We do have a very simple large-scale storage system that's already in use across the world: pumping water uphill. It's just not as economical as rain when you factor in the efficiency losses from generating and transferring power twice.

rurounijones 8y ago
And pumping water uphill is a regional solution that requires specific regional geography, to me that does not class as "scalable". I should be more specific in that to me "scalable" is a solution that can be deployed anywhere without require specific regional properties. Maybe you think this is unneeded and that a lot of region specific solutions can cover the storage requirements. However another posted did point out that 1 mile by 1 mile of batteries is apparently enough to store US energy requirements.
- ShorsHammer 8y ago
  Unless there is big improvements in battery tech I don't see it as a solution. Lithium batteries have their own environmental problems and die after 10 years. Pumped hydro requires the geography, building new capacity tends to flood large areas and release huge amounts of greenhouse gases initially. Simply lifting weights on cranes or rail tracks is looking more efficient and can be adapted anywhere. It will probably win out in many cases.
  - usrusr 8y ago
    > Simply lifting weights on cranes or rail tracks is looking more efficient and can be adapted anywhere. The energy density of that kind of scheme is a joke. Thought experiment: a fully charged Tesla, how often could it climb a hill the size of that crane if it skips recuperation on the downhill leg? That's how much lower the energy density of a crane storage would be. Pumped storage works (where the geography allows it) because water is by far the cheapest and the most easily transported ballast and geographic height differences dwarf almost every human made structure. If you want something that scales everywhere, look no further than compressed air. It's usually ignored because of the big thermal losses, but if you have a direct application for coolant they are not that bad and even without, it serves as an almost trivial lower bound to the storage problem. We can calculate how much intermittent energy production we would need with compressed air to serve a power demand profile and everything else is just a possible improvement.
    - ShorsHammer 8y ago
      Since when was energy density ever been a problem for grid storage? Even in the most crowded cities on earth it's not a constraint. Unless you are talking about portable applications it's all about round trip efficiency and cost, I'm not sure if you are getting confused about terms here or talking about an entirely different subject. Compressed air efficiency isn't great. Using it for cooling lowers the efficiency even more. Crane and rail gravity storage are pushing 80-90% round trip efficiency. Previous HN discussion: https://news.ycombinator.com/item?id=17789456 https://news.ycombinator.com/item?id=17789456
- rjf72 8y ago
  It doesn't require specific geography. You can create entirely artificial pump systems isolated from any natural water. These are called closed loop systems. You could create an closed loop pumped hydroeletric system in the middle of the Sahara if so desired. Incidentally you could power the entire world with a solar area taking up a single digit percent of the Sahara. These haven't been actively developed in the past because we don't have much need for massive storage and they also take something on the order of a couple of years to plan, develop, and execute. You need the demand to be there before the storage is built, but the demand won't exist until the storage is built. Fun problems. Because of this batteries are a more practical immediate solution. They can be deployed anywhere, at practically any scale, with negligible time requirements. And similarly for manufacturing. Since they aren't 'geo locked' their market flexibility is much greater.
  - dredmorbius 8y ago
    The Sahara-global-solar-facility scale starts bumping up a lot when you factor in realities. PV efficiency, spacing factors, panel replacement cycles, storage requirements, the fact that we're looking at total energy use and not just electricity, first-world rather than third-world per-capita use rates (presuming we're not going to freeze the entire world at its present state of energy consumption), and projected population growth. You can still provide most or all the hypothetical demand from the Sahara, but you're well above 1% land use. I've sketched this out elsewhere previously, don't have numbers handy. Beware optimistic estimates.
    - rjf72 8y ago
      I worked out the numbers several years back and it was around 5%. Efficiency improvements since then should have improved this a fair amount. Even if you bump it up by an order of magnitude it's still rather remarkable how easily we could power the entire world on solar alone. However, I completely agree on the real issue being one of longterm consumption. I would say this is something that's regularly ignored. The developing world starting to consume developed world electricity/capita alongside increasing world population is easily going to increase energy consumption by some orders of magnitude in the foreseeable future. This poses unique challenges few are considering. For instance nuclear also runs into problems here with resource availability. The technology is already rather cost prohibitive and for future energy needs if it became a primary source you'd absolutely need to move to breeder reactors alongside saltwater uranium extraction which would both push the prices up significantly higher than even present. High energy demands alongside high energy prices might make the production owners/shareholders happy, but not much of anybody else. In any case sooner or later we'll end up relying on solar simply because nothing else can compete on gross energy availability. The sun's a fusion reactor that could fit about 1.3 million Earths inside of it. That enables practically unlimited power out there just waiting to be harnessed one way or the other.
- dv_dt 8y ago
  Nuclear power plants are also regional solutions that requires specific geography....
  - dredmorbius 8y ago
    Nuke plant siting is vastly less constrained than pumped hydro facilities.

rurounijones 8y ago

And pumping water uphill is a regional solution that requires specific regional geography, to me that does not class as "scalable". I should be more specific in that to me "scalable" is a solution that can be deployed anywhere without require specific regional properties. Maybe you think this is unneeded and that a lot of region specific solutions can cover the storage requirements. However another posted did point out that 1 mile by 1 mile of batteries is apparently enough to store US energy requirements.

ShorsHammer 8y ago
Unless there is big improvements in battery tech I don't see it as a solution. Lithium batteries have their own environmental problems and die after 10 years. Pumped hydro requires the geography, building new capacity tends to flood large areas and release huge amounts of greenhouse gases initially. Simply lifting weights on cranes or rail tracks is looking more efficient and can be adapted anywhere. It will probably win out in many cases.
- usrusr 8y ago
  > Simply lifting weights on cranes or rail tracks is looking more efficient and can be adapted anywhere. The energy density of that kind of scheme is a joke. Thought experiment: a fully charged Tesla, how often could it climb a hill the size of that crane if it skips recuperation on the downhill leg? That's how much lower the energy density of a crane storage would be. Pumped storage works (where the geography allows it) because water is by far the cheapest and the most easily transported ballast and geographic height differences dwarf almost every human made structure. If you want something that scales everywhere, look no further than compressed air. It's usually ignored because of the big thermal losses, but if you have a direct application for coolant they are not that bad and even without, it serves as an almost trivial lower bound to the storage problem. We can calculate how much intermittent energy production we would need with compressed air to serve a power demand profile and everything else is just a possible improvement.
  - ShorsHammer 8y ago
    Since when was energy density ever been a problem for grid storage? Even in the most crowded cities on earth it's not a constraint. Unless you are talking about portable applications it's all about round trip efficiency and cost, I'm not sure if you are getting confused about terms here or talking about an entirely different subject. Compressed air efficiency isn't great. Using it for cooling lowers the efficiency even more. Crane and rail gravity storage are pushing 80-90% round trip efficiency. Previous HN discussion: https://news.ycombinator.com/item?id=17789456 https://news.ycombinator.com/item?id=17789456
rjf72 8y ago
It doesn't require specific geography. You can create entirely artificial pump systems isolated from any natural water. These are called closed loop systems. You could create an closed loop pumped hydroeletric system in the middle of the Sahara if so desired. Incidentally you could power the entire world with a solar area taking up a single digit percent of the Sahara. These haven't been actively developed in the past because we don't have much need for massive storage and they also take something on the order of a couple of years to plan, develop, and execute. You need the demand to be there before the storage is built, but the demand won't exist until the storage is built. Fun problems. Because of this batteries are a more practical immediate solution. They can be deployed anywhere, at practically any scale, with negligible time requirements. And similarly for manufacturing. Since they aren't 'geo locked' their market flexibility is much greater.
- dredmorbius 8y ago
  The Sahara-global-solar-facility scale starts bumping up a lot when you factor in realities. PV efficiency, spacing factors, panel replacement cycles, storage requirements, the fact that we're looking at total energy use and not just electricity, first-world rather than third-world per-capita use rates (presuming we're not going to freeze the entire world at its present state of energy consumption), and projected population growth. You can still provide most or all the hypothetical demand from the Sahara, but you're well above 1% land use. I've sketched this out elsewhere previously, don't have numbers handy. Beware optimistic estimates.
  - rjf72 8y ago
    I worked out the numbers several years back and it was around 5%. Efficiency improvements since then should have improved this a fair amount. Even if you bump it up by an order of magnitude it's still rather remarkable how easily we could power the entire world on solar alone. However, I completely agree on the real issue being one of longterm consumption. I would say this is something that's regularly ignored. The developing world starting to consume developed world electricity/capita alongside increasing world population is easily going to increase energy consumption by some orders of magnitude in the foreseeable future. This poses unique challenges few are considering. For instance nuclear also runs into problems here with resource availability. The technology is already rather cost prohibitive and for future energy needs if it became a primary source you'd absolutely need to move to breeder reactors alongside saltwater uranium extraction which would both push the prices up significantly higher than even present. High energy demands alongside high energy prices might make the production owners/shareholders happy, but not much of anybody else. In any case sooner or later we'll end up relying on solar simply because nothing else can compete on gross energy availability. The sun's a fusion reactor that could fit about 1.3 million Earths inside of it. That enables practically unlimited power out there just waiting to be harnessed one way or the other.
dv_dt 8y ago
Nuclear power plants are also regional solutions that requires specific geography....
- dredmorbius 8y ago
  Nuke plant siting is vastly less constrained than pumped hydro facilities.