Some key insights from the article:
Basically, what they did was to look at how much batteries would be needed in a given area to provide constant power supply at least 97% of the time, and the calculate the costs of that solar+battery setup compared to coal and nuclear.
Yeah I was just explaining why I think the disconnect shows up between percentage and the number. Its why as you get to the end each percentage become significant as it means just a bit more insulation, batter size, panel efficiency, appliance efficiency might bridge the gap. You get in the nineties and its that one most brutal month that it can't handle.