California accounts for 24.3% of US charging connections, but 31.9% of EVs – so the EV to charging connection ratio is higher than for the total US.
What is the needed ratio? That is a complex question – the IEA has said 10 to 1 for Europe, but my last estimate for Norway, the country with the highest percentage of EVs, was at roughly 31 to 1 – though there are reports of long wait times now in Norway. In my 2019 EVAdoption article, What Is The “Minimum Acceptable” Ratio Of EVs to Charging Stations, I estimated that 15-20 EVs to 1 charging connection should be enough for the next 5-7 more years.
But factors that affect the needed ratio include the mix of BEVs versus PHEVs, average range of BEVs, percentage of renter versus homeowner households who drive EVs, how fast BEVs and DC fast charging stations can charge, growth in remote workers, and more.