Interesting. Never heard of this being done in practice before, do you have references of what you're referring to?
It's not done in practice because we don't actually have that much spare renewable energy capacity. Whenever renewables power 90%+ of current usage it tends to hit the news. It's not common. 100%+ is pretty much unheard of.
Pretty much every MWh generated by green energy these days is just a MWh of natural gas extracted from the earth that is not burned.
This is a hypothetical solution to solar and wind routinely overproducing what batteries and pumped storage can keep up with.
But as a technology it exists. The early outputs will be for things that can't be replaced with cheap renewable generated electricity, like e-fuels for spacecraft, which Tesla is doing in Texas.
In fact it's so much cheaper that it's even more economic to use solar/wind to synthesize natural gas and burn that to generate electricity.
Never mind all of the cheaper short term storage options (pumped storage, batteries).
And this doesnt even account for the storage nuclear power would need (it's even less economic to use it for load following) or the need for taxpayer indemnification against catastrophe cleanup costs.