Comment by mr_toad
3 days ago
Maybe use excess power to produce methane via the sabatier reaction, store that, and then burn it in turbines or use it in fuel cells when needed.
It’ll be interesting to see how the economics of these various solutions play out.
The problem with that is usually efficiency. Electrochemical or thermal production of methane from CO2 and H2O is not very efficient, and then you're burning it, which is only heat engine efficiency.
Batteries or direct mechanical storage (compressed gas, pumped hydro, etc.) are both a lot more efficient.
This would make sense if solar gets so cheap that it's something to do with the surplus, and it would be a way to electrify things like long haul aviation where batteries are too heavy. We are flying LNG rockets, so LNG planes are totally possible, or you could upgrade methane to butane or propane which are quite easy to compress to liquid form. Jet engines run great on light weight fuels like that.