Oops, seems my split second skim of Wikipedia was a shortcut too far. :) I had to look up a quad (a short-scale quadrillion BTU). Haven't come across British T

Oops, seems my split second skim of Wikipedia was a shortcut too far. :) I had to look up a quad (a short-scale quadrillion BTU). Haven't come across British Thermal Units in Britain for decades! Anyway. 100 of that scale might be better or easier as 1,000 smaller capacity, but even then we can reduce further. Some percentage of the grid is nuclear (roughly 20% of US electric) which would not need underwriting nor would 100% of continental wind power ever be becalmed. I would further assume that any concerted national effort to electrify carbon neutrally would come with a matching efficiency drive - insulation, tax inefficient users, take first steps toward a national grid (that TIL the US apparently does not have), etc to allow you to use the power you have rather better. Yet ignoring all that, the US must have thousands or tens of thousands of disused mines and quarries, probably many open ones with an accidental lake in their place that could be repurposed. If there's adequate volume, you don't need much head of water. There's no shortage of hills and mountains with rainfall or snow melt that should give plenty of potential spots, population and environment permitting. The one thing America does not lack is space - of all terrain types.