> "what happens when the wind is not blowing or the sun is not shining?"
You ramp up your hydro output and spread out and postpone the load. People have adapted to doing dishes and laundry when electricity is cheap, this is not different.
If you are relying on wind and solar, then you will need energy storage. You will have to take the losses into account. You’ve already admitted this partially by acknowledging 25% losses with pumped hydro. But not everywhere has pumped hydro, nor hydropower at the scale needed.
The point is that hydrogen gives you nearly lossless energy storage. This is why simplistic accounts of efficiency are simply wrong. People are ignoring energy storage losses on the BEV side, but always bring up the full cycle losses on the hydrogen side. This is an apples-to-oranges comparison, and gives you an invalid conclusion.
You ramp up your hydro output and spread out and postpone the load. People have adapted to doing dishes and laundry when electricity is cheap, this is not different.