- pumped-hydro won't work because there are very few places that have the conditions to enable it. Hydro in general is great, but we've pretty much dammed every river that can be dammed.
- batteries won't work because there is no technology today or incoming that can a) store enough to power a city for hours, days, or weeks and b) can even main storage across weeks or months (as would be needed since wind/solar varies seasonally and yearly)
