California's state legislature recently approved a bill requiring the state to get 100 percent of its electricity from carbon-free sources by the year 2045. It's a landmark for power sector decarbonization, and if Gov. Jerry Brown signs the bill, it will require a transformation of the state's energy system.

California already gets 29 percent of its electricity from zero-carbon wind, solar, biomass and geothermal energy, and it has already reduced statewide greenhouse gas emissions to 1990 levels. However, emissions in the state's biggest emitting sector, transportation, have barely budged this century.

That's why the state's electric vehicle market is increasingly important, and worth a close look. The latest monthly electric vehicle tracker from my Bloomberg NEF colleagues shows some important developments in America's biggest state auto market.