Electrolysis efficiency is a lot higher than that although of course the round-trip is much worse than batteries. You can in fact use the existing gas distribu

Electrolysis efficiency is a lot higher than that although of course the round-trip is much worse than batteries. You can in fact use the existing gas distribution grid although not most of the transmission grid because of material compatibility issues. The one area where I think hydrogen can be hard to beat in areas with the geology for it is as an inter-seasonal energy store in salt caverns. Diurnal storage is obviously a battery play but in a deeply decarbonised system (<10gCO2/MWh) you end up with needing something to provide energy during a few-week-long period of overcast and windless weather (that coincides with the coldest period of the year in NW Europe). For lower levels of decarbonisation, you can just keep your gas generation around and fire them up for a few weeks a year but once you go all the way close to net zero you either need: CCS (unproven, not everywhere has the right geology) Lots of nuclear... but although plants can technically operate in load following mode, the plan economics (low marginal cost, high capital cost) don't support that. Batteries at a scale and a cost that don't seem plausible even with the most aggressive LiOn learning rates H2 storage in salt domes Something else? Part of the problem is that the high capital cost of H2 electrolysis and fuel cells doesn't really support a model where you only produce during the cheapest / windiest 1000 hours of the year and consume during the least windy / most expensive 1000. Really you want an electrolyser fuel combo that has today's so-so performance but low capex, that would be much more compatible with a plan to use it as bulk energy store.