You can have natural gas backup generating capacity equal to most demand--but which is used only a few days a year. This 95% Green solution is going to be a lot cheaper and more reliable than a 100% Green solution.
Right now our energy is roughly 5-10% green. Arguing whether green energy should eventually be 95% or 100% is purely pedantic at this point. There is approximately 95% of common ground between green energy purists and pragmatists. Lets get in line.
https://ww2.energy.ca.gov/almanac/electricity_data/total_sys...
Large Hydro 10.68%
Renewables (including geothermal, solar, and wind) 31.36%
Nuclear 9%