3 ms·

The square-root scaling law means quadrupling the water storage only doubles the length of the perimeter dike. It is a good thing. Dikes are as mature as any t

The square-root scaling law means quadrupling the water storage only doubles the length of the perimeter dike. It is a good thing. Dikes are as mature as any technology still in use: they predate writing. We don't need to guess what they cost. We have, similarly, well beyond a century of experience with penstocks and kinetic waterwheels. Pumps have been in use for some time, too.

Schroedingersat 4y ago
> The square-root scaling law means quadrupling the water storage only doubles the length of the perimeter dike. It is a good thing. Only if there is a project of reasonable size that has a manageable cost. Otherwise the corolloray that smaller dikes cost more implies that only a small handful of perfectly placed megaprojects will work. Responding with vague rhetoric for something you claim will work when there are hard numbers for finished projects using other technologies makes you look no better than the fission shills. Snowy 2 blows fission out of the water, even being over budget by the usual fission ratio. But it had a watershed and it wasn't greenfield. Are there any actually existing off river PHEL projects (or adequately sized reservoirs) with real budgets that actually got finished to compare?
- pencilguin 4y ago
  California, in particular, has a century of experience with alpine reservoirs, penstocks, and kinetic water wheel generation; and have recently retrofitted pumping. A century ago they built earthen dams up there using earth-moving equipment with parts operated by cables on pulleys, because hydraulics were not mature. The roads are still used today, mainly for recreation, and are execrable, but sufficed.
  - Schroedingersat 4y ago
    This is more vague hand waving. But it did at least lead to an (unfinished) project with a budget. Eagle mountain is a brown field off river PHES project. Is it fair to say brown field projects are no more expensive than green? It has 430m of head which is a fairly good site and a grade of about 30% which is excellent (so cost of power is minimized). Most cost grade A sites should be worse than this. Cost: $2.5bn Power: 1.3GW Capacity: 18GWh or 14hr Cost $138/kWh Assuming half is the power infrastructure then cost of capacity is about $70/MWh. The long term cost of a hole is about as close to zero as you want, but O&M costs $10 to a few tens of $ per MWh for existing hydro so there is no reason to think O&M would be cheaper than replacing a >5000-8000 cycle cell if it could match up front costs. Compare to $200/kWh for current commercial iron/iron flow or historic lows of lithium (which should be indicative of an upper bound on sodium ion as the manufacturing is similar). CATL and Natron are claiming around $60-90/kWh is achievable for SIB by 2030, and Form energy (less believable but still probable) are claiming an eventual lower bound for Fe-air of $20-50. Seems fair to say raw cost per kWh should favour chemical batteries in many areas by 2030 and LCOS should be on par in 2050s. Cost of power already favours batteries and colocation should favour them further by reducing transmission costs and curtailment. Batteries (except for iron-air) are also faster and more flexible which is why they are replacing gas peakers. Then there are electrolysers which have a high cost per use and per power but vastly lower (effectively free) cost of capacity. Seems like fairly strong evidence that PHES is a poor fit in most areas unless it's huge or started right now. Can you find a better example (ideally one which is finished)?

Schroedingersat 4y ago

> The square-root scaling law means quadrupling the water storage only doubles the length of the perimeter dike. It is a good thing. Only if there is a project of reasonable size that has a manageable cost. Otherwise the corolloray that smaller dikes cost more implies that only a small handful of perfectly placed megaprojects will work. Responding with vague rhetoric for something you claim will work when there are hard numbers for finished projects using other technologies makes you look no better than the fission shills. Snowy 2 blows fission out of the water, even being over budget by the usual fission ratio. But it had a watershed and it wasn't greenfield. Are there any actually existing off river PHEL projects (or adequately sized reservoirs) with real budgets that actually got finished to compare?

pencilguin 4y ago
California, in particular, has a century of experience with alpine reservoirs, penstocks, and kinetic water wheel generation; and have recently retrofitted pumping. A century ago they built earthen dams up there using earth-moving equipment with parts operated by cables on pulleys, because hydraulics were not mature. The roads are still used today, mainly for recreation, and are execrable, but sufficed.
- Schroedingersat 4y ago
  This is more vague hand waving. But it did at least lead to an (unfinished) project with a budget. Eagle mountain is a brown field off river PHES project. Is it fair to say brown field projects are no more expensive than green? It has 430m of head which is a fairly good site and a grade of about 30% which is excellent (so cost of power is minimized). Most cost grade A sites should be worse than this. Cost: $2.5bn Power: 1.3GW Capacity: 18GWh or 14hr Cost $138/kWh Assuming half is the power infrastructure then cost of capacity is about $70/MWh. The long term cost of a hole is about as close to zero as you want, but O&M costs $10 to a few tens of $ per MWh for existing hydro so there is no reason to think O&M would be cheaper than replacing a >5000-8000 cycle cell if it could match up front costs. Compare to $200/kWh for current commercial iron/iron flow or historic lows of lithium (which should be indicative of an upper bound on sodium ion as the manufacturing is similar). CATL and Natron are claiming around $60-90/kWh is achievable for SIB by 2030, and Form energy (less believable but still probable) are claiming an eventual lower bound for Fe-air of $20-50. Seems fair to say raw cost per kWh should favour chemical batteries in many areas by 2030 and LCOS should be on par in 2050s. Cost of power already favours batteries and colocation should favour them further by reducing transmission costs and curtailment. Batteries (except for iron-air) are also faster and more flexible which is why they are replacing gas peakers. Then there are electrolysers which have a high cost per use and per power but vastly lower (effectively free) cost of capacity. Seems like fairly strong evidence that PHES is a poor fit in most areas unless it's huge or started right now. Can you find a better example (ideally one which is finished)?