Comment by eigenspace

I know less about the UK's electrical grid, but at least in Germany, if renewables plus batteries are enough to cover electricity needs for normal day-to-day weather, there is more than enough biogas production in the country to save and store that biogas for the weeks-at-a-time periods where renewable shortfalls happen and batteries won't be enough to cover it.

On any given day Germany generates 7-8% of its electricity from biogas, which means that if instead of burning that gas each day for electricity, we stored it in our network of gas reservoirs, then every 13 days of the year that we don't dip into those reserves, that's a full day of electricity generation in gas that's stored.

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Even if this is done with fossil-gas instead of biogas though, simply having enough renewables + batteries to cut gas out of day-to-day electrical generation, and using it only for backup would be enough to drastically lower prices for the majority of the year.