The state’s electric grid was experiencing rapid and unprecedented changes even before Pacific Gas & Electric and Southern California Edison began shutting off power to millions of people in a desperate scramble to prevent their transmission lines from sparking wildfires.

Solar and wind power were booming. Gas-fired power plants were shutting down. Investor-owned utility companies such as PG&E and Edison were being replaced by city-run alternatives. And the falling cost of lithium-ion batteries was making some households less reliant on the grid than ever before.

The changes will only accelerate in the coming years, as California ramps up efforts to fight climate change by cleaning up its energy supply.