And which solution is that? Lithium ion batteries? To put this in perspective,
global lithium ion battery output [1] annually doesn't amount to 1 hour's worth of US electricity usage (500 GWh). Hydroelectric storage? You essentially need to repurpose an alpine lake as a dam. That's geographically dependent, and it's dubious it'd scale well as viable hydro sites become more and more remote. The remaining things like electricity-to-gas, or thermal storage only exist in prototypes, and might not even be feasible let alone viable.
In response to your edit:
> As solar and wind costs continue down, synthesizing methane and kerosene from captured CO2 and synthetic hydrogen will shortly be cheaper than mining, refining, and transporting them, even without the carbon taxes. Synthesis of those, and of ammonia and hydrogen itself will absorb unlimited "overbuilt" peak generating capacity, and stocks of all of those serve as storage.
Nobody has successfully built a grid-scale energy-to-gas plant, ever. It remains the stuff of prototypes. This approach is very much in the "hypothetical" phase. There are serious unsolved problems in energy-to-gas:
* It needs a source of carbon to convert H2 to methane. This could come from biofuels, but those aren't available in sufficient supply.
* Producing large quantities of hydrogen without CO2 emissions remains difficult. Almost all methane comes from steam reformation (CH4 + 2O2 -> CO2 + 2H2), which emits carbon dioxide. Electrolysis can't be done effectively.
Currently, power to gas storage is way more expensive than either lithium ion or hydroelectric storage and it's unclear whether it'll ever be cheaper than existing options.
1. https://www.spglobal.com/marketintelligence/en/news-insights...