alt Hacker NewsThe issue is long term, high capacity storage. To store enough energy to last an entire winter using batteries just isn’t practical today. I think you’d need around 100 power walls at today’s capacity to make a house completely off grid, meaning you store excess solar from the summer and draw it down in the winter. With hydrogen stored in pressurized tanks, a 20 m3 tank could be enough to last the whole winter, which seems much more practical than 100 powerwalls.
I think this could be a solution if you wanted a fully off grid, solar powered house, or perhaps if we collectively decide to generate more electricity at home and not rely so much on the grid.
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Storing hydrogen in big underground salt caverns at reasonable pressures and converting it back into electricity in a big power plant is probably more efficient and safer than storing it in millions of tanks in cellars at 700 bar and using small fuel cells to turn it back into electricity.
Oh sure, batteries are completely inappropriate for seasonal storage. But for a home I think a synthetic liquid fuel would be better than hydrogen. Seasonal storage at grid scale is rather different; there I suspect thermal storage will win, if it is brutally cost optimized (so-called sand batteries don't qualify; their capex is too high.) Unfortunately thermal seasonal storage for an individual home isn't very practical; it could be for a village.