California leads the nation in energy-efficiency standards, thanks to legislation that aims to reduce greenhouse gas emission levels by 2020 through smarter energy use and adopting renewable technologies. How is the cap-and-trade program performing in cutting emissions and generating revenue? What’s our track record in implementing solar, wind and other forms of renewables? Is additional innovation needed to move the state beyond dependence on carbon-based systems? Can the energy grid of the future accommodate the demands of a growing population?