This is silly. If the power is only up 95% of the time, nearly everyone will buy natgas/propane generators and then you’ve wasted a lot of effort going green. And that’s 95% on top of our normal outages which aren’t from production issues, but delivery.
"A US energy grid run entirely on renewable energy (at least 95 percent of the time), leaning primarily on energy storage to provide grid flexibility, may be more realistic, and closer to hand, than conventional wisdom has it."
Important to remember that current technology isn't 100% reliable. turbines fail, support systems fail, hot weather reduces effective capacity because steam doesn't condense efficiently into warmer surroundings.
I haven't read the original paper... it sounds as if they're comparing 100% renewables at 95% and 100% reliability against the current mix at current reliability levels. Is that correct?