[_aavaa_]

> Which energy storage losses am I ignoring?

Pumped hydro is energy storage that you have to put energy into to push water uphill. And yes it has losses, 25% losses round trip.

If you have a hydroelectric damn however, you increase the flow when the sun doesn't shine or the wind doesn't blow and curtail it otherwise.

> It also requires you to have hydropower.

It's true. Just as wind turbines needs good wind, solar needs ample sunlight, and hydrogen proposals need large underground caverns.

[_hypx]

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.