[dredmorbius]

Again: the size is incidental to that specific dam. Pumped hydro facilities can be vastly smaller.

Ffestiniog Power Station in the UK is on the order of 1 hectare (1/100 km^2) in area (based on 170,000 m^3 storage and a 34m dam height). It's a modest and early pumped-hydro facility.

https://en.wikipedia.org/wiki/Ffestiniog_Power_Station

Bath County Pumped Storage in the US has an upper reservoir of 107 and a lower of 226 hectares respectively, or 1 km^2 and 2 km^2, roughly. It is the largest in the US.

https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...

There is no reason for a purely pumped-hydro facility to be anywhere remotely near the size of Itaipu. Which is not in fact a pumped hydroelectric storage facility, but a hydroelectric generating station with no pumped-hydro storage capabilities or functions.

https://en.wikipedia.org/wiki/Itaipu_Dam

A red herring.

[keanzu]

You are reading words that aren't there. The top level comment this thread started with is:

>You couldn't be more Dam wrong.

I am talking about dams, not pumped storage.

[dredmorbius]

And that comment responded to "Energy storage isn't really feasible".

And was followed up, by the same author, with another post specifically about pumped storage: https://news.ycombinator.com/item?id=21479576

That we're still discussing this over 24 hours later may strike someone as amusing, but the jokes gone rather stale.

Cheers.