California is marching quickly toward a 100 percent renewable energy mandate with passage of SB 100 by the state’s Assembly, which will require — if ratified into law — the state to receive 50 percent of its electricity from renewables by 2026; 60 percent by 2030, and 100 percent by 2045.

Eligible renewables specified in the state's Renewables Portfolio Standard include solar, wind, geothermal and some hydroelectric generation.

To reach 100 percent clean energy by 2045, California also can draw upon energy sources that aren't strictly renewable, but don’t emit carbon dioxide — such as nuclear, large hydroelectric and natural gas plants with carbon capture and storage to count toward the remaining 40 percent, Popular Science reports.

The current law requires the state to get 50 percent of its electricity from renewables by 2030. California would join Hawaii as the nation’s second state to do go carbon-free.

SB 100 follows a separate environmental bill — SB 32 — that requires the state to limit statewide greenhouse gas emissions to 40 percent below 1990 levels by 2030.

The state is already close to meeting its first benchmark to increase its renewable energy portfolio to 33 percent by 2020, in line with state law SB 350.

"We are already seeing the impacts of climate change. Our state is burning, our seas are rising and our air quality is getting worse. We need to take steps now to stave off climate change before it's too late. SB 100 is a step in the right direction," said Dan Jacobson, director of Environment California, in a statement.

"California just became the largest economy in the world to commit to a 100 percent clean energy grid," said Paul Cort, the Earthjustice attorney who leads the California Right to Zero campaign, in a statement.

Opponents worry about increasing electricity costs and reliability issues, but environmental advocates and proponents are rejoicing.

In 2017, about 29 percent of California's electricity came from renewable energy sources, almost triple the amount from 2007; natural gas and coal made up 34 and 4 percent of California's electric generation in 2017, respectively, down from about 46 and 17 percent in 2007.

The state does get about 10 percent of its energy from its remaining nuclear power plant, Diablo Canyon, however, but it's unlikely that California will be expanding its nuclear energy output. Diablo Canyon will close — if the plan remains in play — in 2025. Additionally, a state law prohibits the construction of new nuclear plants until the government finds a way to safely store the radioactive spent fuel.

Alternatively, the kilowatt-hour price of electricity from new onshore wind and hydroelectric facilities is less than from new conventional energy sources. "Add in externalities from fossil-fuel derived energy, including impacts from air pollution that harms human health and the environment, and solar energy becomes more affordable in the long run as well," Popular Science reported.

SB 100 is a patch, in theory, to get the state on a path toward 100 percent renewable energy even if the ability to do so does not currently exist.

The tapered phase-in approach from now until 2045 gives California flexibility in regard to how it will reach 60 percent renewable energy and become 100 percent carbon-free. Technology improvements and new solutions between now and then will likely fill any gaps, current state leaders hope.

SB 100 will now go back to the full Senate for a final vote, then to Gov. Jerry Brown for signature.