It is understandable that it is desirable to have different forms of the energy back up to achieve 100% renewable energy for all sources. But right now there seems to be this false debate going on insisting that 10x more than the current pumped hydro capacity in the US is needed to get there. One of the chief proponents Mark Jacobson has said this pumped hydro can be achieved by upgrading systems at existing facilities. But it seems non of this is necessary. It seems just building in micro grid back ups with a pure battery solution is enough. This could be done with Tesla Power Packs or similar offerings. Pumped hydro offers a grid fault level back up, but I suspect this can be mimicked by battery solutions in ways that aren't especially elegant but are possible but are also it turns out completely unnecessary if battery back ups are set up strategically to augment the grid. Tesla points out who its even possible to avoid updating grid infrastructure this way- they do so in their marketing literature. But I would say what is happening is grid hardening with this. I do wonder if pumped hydro as part of a strategy of diversity is more resistant to things like EMP pulse but for emergency power the US already has a lot of pumped hydro. On the side of the stupid and the corrupt is the typical fossil fuel industry arguing that a 100% renewable solution is not possible (they don't want the door properly slammed) but they also make stupid resistances about things like carbon capture. But here is the thing, even if cheap effective carbon capture were possible and even if it made fossil fuel cheaper then everything else (not even in the universe of possibility- the only way fossil fuel will every get cheaper is more and increased massive theft from the tax base and that is not cheaper that just greater theft- literally stealth austerity)- even if that were outside the realm of delusional the most important thing at this point is reparation and taking all power and wealth from the criminal contingent behind fossil fuel/energy. If climate change and warming and climate instability weren't real and were just a function of things like HAARP or solar cycle or even if more carbon were slowing an ice age not fomenting it- it would still be radically positive PR because getting rid of fossil fuel-energy power has to be humanities highest priority.