4 ms·

Many of the geographically-convenient spots to do pumped hydro in are already being used, which makes this hard to scale beyond what we currently have.

moloch-hai 4y ago
There is no hint of a shortage of places good for pumped hydro. What is in short supply is existing hydro-power dams that have not yet been retrofitted with pumps. Retrofitting an existing hydro plant is cheaper than building a hilltop reservoir, penstock, turbine, and pump. The latter might cost more than other alternatives. Anywhere that is true, expect to see one of the others used.
- coder543 4y ago
  It's not a question of whether you can, it's a question of whether pumped hydro is cheaper than lithium ion batteries, and that price is heavily influenced by the available geography and water supply. Wherever pumped hydro is cheaper, then by all means, we should build a bunch of it.
  - moloch-hai 4y ago
    It is far from clear which will be the cheapest storage medium, in each place. Count on people to install whatever is cheapest where they are at the time they build. Batteries are expensive right now, but costs are still falling. It is conceivable that a substantial fraction of installed storage will actually end up batteries. My favorite medium, at the moment, is heavy weights hung from a disused supertanker moored over a sea trench. Each weight would have its own cable reel, with clutch and brake, sharing a shaft with the rest, the shaft driven by a winch and motor/generator kept out of the weather. A net full of ironstone riprap would serve for the weight. The winch would be whatever is the biggest available off the shelf, with the weights chosen to match the winch. Maybe 1000 tons each? A supertanker is wide enough for multiple shafts, and you can rack together multiple supertankers. A smallish one can hold up 100,000 tons. Taiwan has an excellent trench right off the SE shore, but there are a lot of near-shore trenches, off SE India, SW Mexico, E Korea, SE Japan, and even Monterey and Monaco. Probably a deep trench is not even needed for viability; 1000 meters is probably plenty. A supertanker seems to run $50-100M new, probably a small fraction as scrap. There will be a lot of supertankers to scrap; it is already starting.

moloch-hai 4y ago

There is no hint of a shortage of places good for pumped hydro. What is in short supply is existing hydro-power dams that have not yet been retrofitted with pumps. Retrofitting an existing hydro plant is cheaper than building a hilltop reservoir, penstock, turbine, and pump. The latter might cost more than other alternatives. Anywhere that is true, expect to see one of the others used.

coder543 4y ago
It's not a question of whether you can, it's a question of whether pumped hydro is cheaper than lithium ion batteries, and that price is heavily influenced by the available geography and water supply. Wherever pumped hydro is cheaper, then by all means, we should build a bunch of it.
- moloch-hai 4y ago
  It is far from clear which will be the cheapest storage medium, in each place. Count on people to install whatever is cheapest where they are at the time they build. Batteries are expensive right now, but costs are still falling. It is conceivable that a substantial fraction of installed storage will actually end up batteries. My favorite medium, at the moment, is heavy weights hung from a disused supertanker moored over a sea trench. Each weight would have its own cable reel, with clutch and brake, sharing a shaft with the rest, the shaft driven by a winch and motor/generator kept out of the weather. A net full of ironstone riprap would serve for the weight. The winch would be whatever is the biggest available off the shelf, with the weights chosen to match the winch. Maybe 1000 tons each? A supertanker is wide enough for multiple shafts, and you can rack together multiple supertankers. A smallish one can hold up 100,000 tons. Taiwan has an excellent trench right off the SE shore, but there are a lot of near-shore trenches, off SE India, SW Mexico, E Korea, SE Japan, and even Monterey and Monaco. Probably a deep trench is not even needed for viability; 1000 meters is probably plenty. A supertanker seems to run $50-100M new, probably a small fraction as scrap. There will be a lot of supertankers to scrap; it is already starting.