Gov. Jerry Brown signed legislation Wednesday mandating that half of the state's electricity come from renewable sources by 2030 and calling for a doubling of the energy efficiency of buildings.

The signing took place at the Griffith Observatory, overlooking Hollywood and the Los Angeles basin.

"The goal is clear, and California is in the forefront," Brown said.

The ambitious mandates of SB 350, championed by Senate President Pro Tem Kevin de Leon, D-Los Angeles, were outlined by Brown in his inaugural address in January. But de Leon's legislation was significantly changed last month in the state Assembly, which stripped away a requirement that the state slash its gasoline use by 50 percent in the next 15 years.

That provision sparked debate in Sacramento.

Democratic leaders blamed the gasoline provision defeat on a multimillion-dollar advertising campaign by oil companies. Many moderate Democrats also expressed concern that the petroleum-reduction mandate would hurt California's working-class residents.

Despite the loss of the gasoline provision, de Leon said the legislation still includes steps that "build on California's historic commitment to lead the world in the fight against climate change and build a healthy and livable planet for our children and grandchildren.

"But our efforts to reduce carbon emissions are far from over as global warming and air pollution remain one of the most important issues of our generation and one of the greatest threats for generations to come," he said.

The signing marks an end to a nearly yearlong effort by Brown to push for stricter standards.

The governor began the year with a proposal for the state to set the most aggressive greenhouse-gas emissions benchmark in North America. He discussed global warming concerns with the pope at the Vatican in July and met with other leaders around the world on the issue.

After previous environmental efforts, California is already on target to generate at least a third of its electricity from renewable sources by 2020. The final bill Brown is considering Wednesday defers to state regulators to implement the programs to increase renewable electricity use and double energy efficiency in existing buildings.

Some Republicans expressed disappointment that the bill won't count homeowners who have installed rooftop solar panels toward the 50 percent renewable goal.

"We should not be excluding the 200,000 Californians who are doing their part to make clean energy a reality," said Assemblyman Brian Jones, R-Santee.

