6 ms·

> There are not enough sites... This is always claimed, and is always false. Please do not repeat falsehoods. Existing hydro generation needs a watershed. Pum

by ncmncm 4y ago

> There are not enough sites... This is always claimed, and is always false. Please do not repeat falsehoods. Existing hydro generation needs a watershed. Pumped hydro does not. All it needs is a disused hilltop and earthen dike, and not always the dike. It doesn't always need the hill: underground cavities work to pump water up out of, and to drain into. Batteries will always be the most expensive alternative. They will be used in limited amounts, mainly for very short-term (overnight) storage.

Schroedingersat 4y ago
> It doesn't always need the hill: underground cavities work to pump water up out of, and to drain into. Do you have any good numbers on real world projects? I'm very happy to be wrong here, but all the numbers I can find are either lies from nuclear shills or using existing watersheds. Most also only focus on the cost per kW which is higher than batteries and not the relevant metric (as batteries can drain in a few minutes) for season-long storage. Also a quick back of the envelope seems to suggest emptying and filling lake Baikal could store as much energy as about a billion tonnes of chemical storage. This seems like a reasonable upper bound which would indicate pumped hydro is about an order of magnitude short of solving the problem. Current battery production is nowhere near (total cumulative seems to be about a megatonne chemical equivalent even if it is more than doubling annually it'll take over a decade to catch up), but this is expected because batteries are optimal for short term. Overall by gut feel it seems a more feasible to make and store ten cubic kilometers of chemical fuel worldwide than move 200,000km^3 of water around.
- ncmncm 4y ago
  Most current pumped hydro uses existing dams because duh. But nobody is building those anymore, for reasons you note. Existing hydro power dams were expensive because they needed to be deep to store years of water, and concrete because deep water has high pressure. They destroy ecosystems because that is where the water comes from. Dedicated pumped hydro storage is typically quite shallow, with an earthen dike (if needed at all), and the only place with high pressure is at the bottom end of a penstock. It does not need to store years of water; just a day's worth is useful.
  - Schroedingersat 4y ago
    A day's worth puts it in the power limited regime where $100/kWh 4C batteries are already close to viable, and can use the 50x higher power per $ and higher efficiency for minute by minute arbitrage to offset costs. Do you have sources for real projects that can beat $60/kWh capacity and $600/kW power (what you'd be competing with by the time construction finished)? Moreover it also needs to beat hydrogen or methane storage (electricity->chemical-electricity) which (sans capex for tanks because I can't find good numbers, but I think it adds about 20%) is about $100/MWh out and $1000/kW using current technology including energy and projected to fall to somewhere around $40 and $500 in realistic timescales. To make it impossible to mine more fossil fuels even for a mixture of slave-driving sociopaths unrestrained by law and theocrats actively seeking apocalypse we need to be able to use a MWh at night in mid winter that was produced at 2pm in summer for less than around $40 and then do it another billion times without hitting some resource limit. Hydrogen with storage is shockingly close, and if synthetic ammonia/methane or metal hydride get over the line, noone will look at fossil fuels again. You seem to be telling me that pumped hydro is already there, but I can't find a decent source agreeing with you (or any numbers dealing with this use case for that matter).
    - ncmncm 4y ago
      What I am saying about pumped hydro is that it is deeply mature technology, with no surprises in store. All the equipment is essentially unchanged for decades, except for control-system electronics. All that is new is reservoirs not fed by watersheds. There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up.
      - Schroedingersat 4y ago
        > What I am saying about pumped hydro is that it is deeply mature technology, with no surprises in store. All the equipment is essentially unchanged for decades, except for control-system electronics. All that is new is reservoirs not fed by watersheds. And I can attach a washing machine motor to my water tank. If it produces basically nothing and costs double the alternative, it's not relevant to the discussion. > There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up. So there are no new projects which not destroying an ecosystem that are on cost parity with batteries then? Also as an aside, how pathetic is capitalism as an organizational system that we can't achieve the types of things that were done with horses and carts and pulley bulldozers in the past?

by ncmncm 4y ago

Schroedingersat 4y ago

> It doesn't always need the hill: underground cavities work to pump water up out of, and to drain into. Do you have any good numbers on real world projects? I'm very happy to be wrong here, but all the numbers I can find are either lies from nuclear shills or using existing watersheds. Most also only focus on the cost per kW which is higher than batteries and not the relevant metric (as batteries can drain in a few minutes) for season-long storage. Also a quick back of the envelope seems to suggest emptying and filling lake Baikal could store as much energy as about a billion tonnes of chemical storage. This seems like a reasonable upper bound which would indicate pumped hydro is about an order of magnitude short of solving the problem. Current battery production is nowhere near (total cumulative seems to be about a megatonne chemical equivalent even if it is more than doubling annually it'll take over a decade to catch up), but this is expected because batteries are optimal for short term. Overall by gut feel it seems a more feasible to make and store ten cubic kilometers of chemical fuel worldwide than move 200,000km^3 of water around.

ncmncm 4y ago
Most current pumped hydro uses existing dams because duh. But nobody is building those anymore, for reasons you note. Existing hydro power dams were expensive because they needed to be deep to store years of water, and concrete because deep water has high pressure. They destroy ecosystems because that is where the water comes from. Dedicated pumped hydro storage is typically quite shallow, with an earthen dike (if needed at all), and the only place with high pressure is at the bottom end of a penstock. It does not need to store years of water; just a day's worth is useful.
- Schroedingersat 4y ago
  A day's worth puts it in the power limited regime where $100/kWh 4C batteries are already close to viable, and can use the 50x higher power per $ and higher efficiency for minute by minute arbitrage to offset costs. Do you have sources for real projects that can beat $60/kWh capacity and $600/kW power (what you'd be competing with by the time construction finished)? Moreover it also needs to beat hydrogen or methane storage (electricity->chemical-electricity) which (sans capex for tanks because I can't find good numbers, but I think it adds about 20%) is about $100/MWh out and $1000/kW using current technology including energy and projected to fall to somewhere around $40 and $500 in realistic timescales. To make it impossible to mine more fossil fuels even for a mixture of slave-driving sociopaths unrestrained by law and theocrats actively seeking apocalypse we need to be able to use a MWh at night in mid winter that was produced at 2pm in summer for less than around $40 and then do it another billion times without hitting some resource limit. Hydrogen with storage is shockingly close, and if synthetic ammonia/methane or metal hydride get over the line, noone will look at fossil fuels again. You seem to be telling me that pumped hydro is already there, but I can't find a decent source agreeing with you (or any numbers dealing with this use case for that matter).
  - ncmncm 4y ago
    What I am saying about pumped hydro is that it is deeply mature technology, with no surprises in store. All the equipment is essentially unchanged for decades, except for control-system electronics. All that is new is reservoirs not fed by watersheds. There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up.
    - Schroedingersat 4y ago
      > What I am saying about pumped hydro is that it is deeply mature technology, with no surprises in store. All the equipment is essentially unchanged for decades, except for control-system electronics. All that is new is reservoirs not fed by watersheds. And I can attach a washing machine motor to my water tank. If it produces basically nothing and costs double the alternative, it's not relevant to the discussion. > There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up. So there are no new projects which not destroying an ecosystem that are on cost parity with batteries then? Also as an aside, how pathetic is capitalism as an organizational system that we can't achieve the types of things that were done with horses and carts and pulley bulldozers in the past?