There's a lot of articles about supply based usage vs demand based energy production on that website. The idea that it turns off every now and then is sort of part of the authors' intention of showing "we can live with some outages".
This article in particular is a good one: https://solar.lowtechmagazine.com/2017/09/how-not-to-run-a-modern-society-on-solar-and-wind-power-alone/
Ah, sorry for the confusion - that server's been out of commission for a few years already.