According to this it was caused by unreliable gas peaking plants much like happened in S. Australia but was also blamed on renewables.
Don't forget the cause of the increasing heat that is increasing demand unless you see climate change as a conspiracy theory.
Batteries are now proving to be cheaper and more reliable than gas so once they are in place the system will be vastly improved.
"But in California these days, it’s natural gas that picks up most of the slack, largely because the state’s nearly 200 plants can respond quickly to upticks in demand.During the recent blackouts, some of these usually reliable sources were unexpectedly unavailable, for reasons that are still not fully clear.Several gas plants that were supposed to provide power failed to operate or tripped off, the CAISO said in a press conference last Wednesday. The state was unable to import power from other states in the region, a strategy it often uses in times of stress, because it was hot everywhere in the West, and other states were facing their own energy shortfalls. Also, because of an ongoing drought, there was less water in the reservoirs that supply many of the hydroelectric plants, meaning they could produce much less power than the CAISO expected."
