One problem with hydro is we've long ago exhausted the easy wins, and then went on to build the kinda wash outs. See the fight over Glen canyon, which even its architect went on to admit was a mistake. The wins now are in closed loop pumped hydro; see https://www.volts.wtf/p/whats-the-deal-with-pumped-hydro

> which even its architect went on to admit was a mistake.

Who are you referring to? A quick Google search didn't confirm what you wrote.