For a very fine overview check out @pfairley.bsky.socialspectrum.ieee.org/methanol-ene...

Backing Up the Power Grid with Green Methanol

A closed-loop storage-plus-power system stockpiles renewable energy wherever it's needed

What's the problem? If wind and solar are the backbone of your system, you need to deal with multi-day periods of low feed-in and variability between years. Fossil+CCS, nuclear, geothermal etc. can help. Storage? Li-ion batteries can't span such long periods because of $$$.