The document summarizes a presentation by Kateri Callahan, President of the Alliance to Save Energy, about the potential for increased energy efficiency. The Alliance is a nonprofit organization that works with public and private sectors to promote energy efficiency. Callahan discusses how energy efficiency has quietly achieved success in reducing costs and emissions. New "game changers" like climate change, energy security concerns, and economic savings create opportunities for much greater efficiency gains. Leadership from companies like Walmart and utilities investing more in efficiency show the enormous untapped potential. Public policy support for efficiency standards, codes, and financing can help efficiency "roar" in the coming decade to address energy and climate challenges.