Earlier this week, the California Assembly took aggressive steps to limit greenhouse gas emissions as legislators voted to require that 100 percent of the state’s electricity come from carbon-free sources by 2045. If signed into law, California would become the most populous state to go completely green in terms of energy production.

SB 100, authored by State Senator Kevin de León, gradually raises California’s renewable energy target to 60 percent by 2030 with interim targets, and gives the state until 2045 to generate the rest of its electricity from carbon free sources. The California Senate already passed an earlier version of the bill last year, 25 to 13, and the Assembly version now heads back to the Senate for final approval before heading to Governor Jerry Brown’s desk.

While following in the footsteps of Hawaii, which is the only other state in the country to require all of its energy to come from clean sources, California’s legislation is distinct from Hawaii’s in that it provides leeway to pursue resources beyond just wind and solar. However, it is not yet clear which, if any, the state will incorporate.

California’s existing large hydropower or nuclear power plants, though they produce carbon-free electricity, do not qualify for the state’s renewable portfolio standard laws, which incentivized new investments in wind and solar over the last decade. The new bill’s requirement of zero-carbon resources, though, broadens the scope of what qualifies under state requirements, leaving an opening for new technologies that may arise in the years to come.

California has long been considered a leader on environmental issues, including imposing stringent fuel-efficiency standards for vehicles that have made it a de facto auto regulator, and requiring solar to be installed on new housing construction. If signed into law, California would again be a bellwether for the sector, forging a path for transitioning to completely carbon-free energy on a mass scale.