That's why you'd usually want to only use the H2 as an intermediate step on the way to some other e-fuel. Which can be as simple as iron powder to be oxidized at the application site. But the first step, in all e-fuel processes, is always the hydrolyser. Coupled with with local H2 storage so that at least the downstream processes can operate closer to 24/7 than the hydrolyser. Batteries don't scale to seasonal, fuels created downstream of a hydrolyser do. The trick is to build the hydrolysers (and downstream processors) at sites where that H2 buffer is easily created. Salt caverns are the usual candidate.

(yes, this is a little off topic under an article about an H2 excavator. But if they solve all those problems, I'll applaude them, because at one point we'll either have green H2 available or we'll cease to be an industrial society, of they don't, well it's their problem they tried, not mine)