California has set a target to reduce greenhouse gas emissions to 40 percent below 1990 levels by the year 2030. To achieve this goal, the California Air Resources Board recommends emissions reductions of 43 to 61 percent below 1990 levels from the electricity sector in particular. The primary vehicle for achieving greenhouse gas reductions from electricity generation is the state’s Renewable Portfolio Standard, which requires retail sales to consist of 50 percent renewables by the year 2030. This paper examines the challenges to creating a low-carbon grid, and discusses the regulatory, infrastructural, and operational changes that will be necessary to achieve California’s greenhouse gas reduction and renewables portfolio standard targets.