I had thought that, until the technology in that link above came out. Ultra cheap thermal storage in dirt, if it works, looks much superior to hydrogen for seasonal grid storage, and has no geographical constraints. Hydrogen really wants salt formations to make cheap solution mined cavities; piles of dirt can be made just about anywhere.

Or indeed methane generated via the Sabatier reaction using hydrogen generated from renewables - higher energy density, easier to handle, store and distribute. And it can be fed to existing gas peaker plants, a known technology.