California just took another step on the road to becoming the second U.S. state to set a mandate that utilities must move towards sourcing 100% of their electricity from renewable energy and other sources that do not emit CO2.

On a 10-5 vote, this morning California time the Assembly Utilities and Energy Committee approved SB100, a bill that will set a 100% by 2045 clean energy policy. The bill now goes to the full Assembly for a vote, and if approved will go to Governor Jerry Brown (D), who is expected to sign it.

SB100 was introduced by former Senate President Pro Tempore Kevin De León (D) in January 2017, and has had a long and arduous path. The bill initially passed the Senate in May 2017, but got stuck in Assembly committees, and it has taken another 10 months to get the bill to where it is today.

Advocates pulled out all the stops to pass the bill through the Utilities and Energy Committee, including delivering 38,000 messages in support of the bill today. SB100 is supported by Vote Solar, Environment California and a number of climate organizations, as well as the American Lung Association.

If passed by the Assembly, California will become the second state to set a 100% mandate, after Hawaii, which also has a timeline of 2045 to reach this target. The next-most ambitious policy is in Vermont, which has set a 75% by 2032 mandate.

However, unlike renewable portfolio standards in Hawaii and Vermont, SB100 is not limited to renewable energy. The bill clearly spells out that utilities must source 100% of their power from renewable energy and “zero-carbon resources”, which could include nuclear power.

However, as the nuclear technologies which are currently commercialized are much more expensive than wind and solar – as well as being unpopular in California – it is unlikely that new nuclear power plants will get built under this policy.

SB100 does increase California’s timeline for implementation, calling for the state’s utilities to procure 60% of their power from renewables by 2030, instead of the current 50%.