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Where does this extra water come from?
by sidewndr46 4y ago
Where does this extra water come from?
- whiddershins 4y agoIt’s just borrowed
- BurningFrog 4y agoHydro power work by water flowing down turbines from a higher body of water to a lower. So you can typically pump the lower water back up, using wind or solar power.
- sidewndr46 4y agoWouldn't this mean the downstream would have no water flowing through it?
- pfdietz 4y agoPumped hydro can be built entirely off rivers. There's a plan to put a reservoir for one on top of a mesa in the desert in Arizona, for example.
- sidewndr46 4y agoWhat does the location of the reservoir matter? If you're taking a river and pumping it up on top of somewhere (a mesa in your example) aren't you going to cause the river to basically run dry everywhere downstream of where your pump is?
- pfdietz 4y agoThere's no river at the bottom, either. I thought the "desert" part would make that clear, but I guess it had to be said. Water in this system is part of the capital cost (charging it up when you start), then a minor maintenance cost (replacing evaporation). Otherwise, unlike primary hydro, there is no large constant flow out of the system, and no need to be on a river. The water lost to evaporation is at least an order of magnitude less than water evaporated from a nuclear plant of the same levelized power.
- sidewndr46 4y agoWouldn't you need two reservoirs in that case? Otherwise where is the water being drained down to take advantage of the potential energy?
- pfdietz 4y agoYes, of course. Off-river pumped hydro involves two reservoirs.
- nirimda 4y agoI think the confusion is a couple of comments up you said "There's a plan to put a reservoir for one on top of a mesa in the desert in Arizona" which is really confusing since of course they're planning to put a pair of reservoirs for one in the desert in Arizona. I guess only one is on top of the mesa though.
- sidewndr46 4y agoSo at that point why use a river? Couldn't you just use ocean water? It's comparatively "free" and we aren't going to run out anytime soon.
- BurningFrog 4y agoWith a high enough plateau near an ocean, that should work. I think those places are really rare though.
- heavenlyblue 4y agoYou need a reservoir to store that water downstream as well, it can't just be a river
- seanmcdirmid 4y agoYa, this is how they do it. Eg see https://en.wikipedia.org/wiki/Dry_Falls_Dam https://en.wikipedia.org/wiki/Dry_Falls_Dam