California has hooked up a grid battery system that is almost ten times bigger than the previous world record holder, but when it comes to making renewables reliable it is so small it might as well not exist.
Mind you the PG&E engineers are not that stupid. They know perfectly well that this billion dollar battery is not there to provide backup power when wind and solar do not produce. In fact the truth is just the opposite. The battery’s job is to prevent wind and solar power from crashing the grid when they do produce.
It is called grid stabilization. Wind and solar are so erratic that it is very hard to maintain the constant 60 cycle AC frequency that all our wonderful electronic devices require. If the frequency gets more than just a tiny bit off the grid blacks out. Preventing these crashes requires active stabilization.
Grid instability due to erratic wind and solar used to not be a problem, because the huge spinning metal rotors in the coal, gas and nuclear power plant generators simply absorbed the fluctuations. But most of those plants have been shut down, so we need billion dollar batteries to do what those plants did for free. Nor is this monster battery the only one being built in California to try to make wind and solar power work. Many more are in the pipeline and not just in California. Many states are struggling with instability as baseline generators are switched off.