Brown signed the bill at a solar panel manufacturing plant near San Jose.
California utilities and other electricity providers will have until the end of 2020 to draw 33 percent of their power from solar panels, windmills and other renewable sources.
Supporters say the increase from the previous law that required 20 percent renewable power will reassure investors and keep money flowing to develop alternative energy sources. They also say the bill will lead to cleaner air and job growth in the clean-energy sector.
But manufacturers and other critics say the higher standard will drive up electricity costs and hurt business competitiveness.
The Associated Press contributed to this story.