The United States is the largest economy and energy user in the world. Significant developments have taken place in its energy policy since the last IEA review in 2002. Most important is the Energy Policy Act 2005 – a comprehensive energy legislation which has set new directions, including opening the way for a nuclear renaissance. Two closely connected challenges shape all debates on the nation’s energy policy path: how to increase security by reducing the dependence on imported supplies; and how to address growing emissions of greenhouse gases. This review takes an in-depth look at these issues and provides recommendations on how the United States can do more to answer the challenges of both improving its security of energy supply and lowering its emissions intensity, demonstrating the significant improvements that can already be realised through existing technologies.