When we get to cheap/common/biodegradable battery material sources such as silicone mixed with iron or aluminum etc, then storage will get interesting.
I think super-capacitors are great for the start-stop, with some type of deep cell or better organic diesel for the continuous runs.
https://www.howtogeek.com/786195/supercapacitors-vs-batteries-whats-the-difference/
Then again, there are other technologies in competition with supercapacitors. The most important of which is the fabled solid-state battery and recently graphene-infused traditional lithium-ion batteries have shown promise as well. Whichever fast-charging, durable, energy-dense technology wins the race, we'll all be winners.
There is also carbon-free solid fuel engines used in rockets but a possible electric plant use.
(if there was a way to 100% capture and recycle the exhaust..)
https://spectrum.ieee.org/metal-powder-a-zerocarbon-fuel-with-promising-properties
After combustion, of course, you’re left with a pile of rust—iron oxide. The usual way of recycling it into iron is to reduce it with coal in a blast furnace. But that, of course, results in carbon emission. But Bergthorson is hopeful. "There are novel techniques to reduce iron oxide using pure hydrogen, or the use of biomass in chemical looping combustion, using gasified biomass or gasified coal, or by electrolysis, which is not yet commercially developed."