Gov. Jerry Brown on Monday signed into law a bill that sets a goal of 100 percent clean electricity for California by 2045.
The goal would require replacing carbon-producing fuels such as coal and gasoline with renewable energy such as wind, solar, geothermal and hydroelectric power.
The law, known as SB 100, also sets goals of 50 percent clean energy by 2025 and 60 percent by 2030.
Brown said in a statement as he signed the law in Sacramento, "California is committed to doing whatever is necessary to meet the existential threat of climate change."
The goal "sends a clear signal to markets to expand clean energy generation," Brown said.
The Sierra Club, noting that California has the world's fifth largest economy, stated, "California is now the largest global economy to commit to 100 percent renewable energy."
"California is showing the world that a transition to 100 percent clean energy is within reach and it will continue to drive the transition away from fossil fuels -- and it is doing this while the federal government abandons clean energy," said Sierra Club Executive Director Michael Brune.
But another environmental group, Greenpeace, said the new law is a good first step, but called on Brown to stop issuing permits for new oil and natural gas wells.
"Continuing to drill and frack for oil and gas is not only counterproductive to efforts to meaningfully address climate change -- it also poisons frontline communities, including the many people who work for the fossil fuel industry," Greenpeace said in a statement.