[ncmncm]

There is no need for batteries to "replace fuels". Batteries are useful in places, but fuels, soon sythetic fuels, will continue to be used, particularly for shipping and aviation. There is no need for pumped hydro to "beat batteries". Both will be used.

There is no shortage of land to use for elevated reservoirs, and (again) no implied threat to watersheds in building them. There is no need for "at least 20 kWh/m^2". Reservoirs have many uses that all add value. They may store energy and water, provide recreation, habitat, irrigation, and a site for solar, all at once. There is no need for them to store 2 months' power. There is very little economy of scale: a dozen reservoirs are as good as one. Construction cost is not proportional to capacity. At worst, it goes as the square root, to build the perimeter dike.

Extraction rate is a question of how big and how many Pelton wheels attached to generation equipment you care to install.

And, as always, immediate and local cost will dictate choice. There is no need for universal numbers or a single answer for everybody.

[Schroedingersat]

> There is no need for batteries to "replace fuels". Batteries are useful in places, but fuels, soon sythetic fuels, will continue to be used, particularly for shipping and aviation. There is no need for pumped hydro to "beat batteries". Both will be used.

Further intntional misrepr#sentation. Batteries solve the short term storage problem (especially sodium ion batteries). You're proposing a much worse solution to the short term storage problem as if it is relevant to the remaining unsolved problem (long term storage). Solving the long term (in space or time) storage problem yields solar supremacy -- conditions in which it becomes untenable to open a new fossil fuel facility or even keep existing ones open in 10 years even with trillions in ongoing subsidies.

> Construction cost is not proportional to capacity. At worst, it goes as the square root, to build the perimeter dike.

You need to make it deeper, or use more land. And when the largest project in the world is at cost parity with batteries in spite of using an existing project and river, that's a damning indictment of anything smaller.

[ncmncm]

Again, there is no value in "solving the long term storage problem". Nobody has any such problem. For reasons already explained several times.

The "largest project in the world" is, by definition, not representative.

[Schroedingersat]

> Again, there is no value in "solving the long term storage problem".

There is, because it is the main impedement to the universality of renewable energy.

> The "largest project in the world" is, by definition, not representative.

Yes. Extremely large, recent infrastructure projects by the CCP tend to have vastly lowe stated costs than anything smaller or in another place. If it's unusual\y expensive, show me one which is representitive. Show me a breakdown of a small project (or any project) which uses a typical hill and costs less than projected battery costs at time of completion.