One of the greatest challenges facing human civilization is the provision of secure, affordable energy without causing catastrophic environmental damage. As the world's largest economy, and as a world leader in energy technologies, the United States is a particularly important case. In the light of increased competition from other countries (particularly China), growing concerns about the local and global environmental impacts of the energy system, an ever-present interest in energy security, and the realization that technological innovation takes place in a complex ecosystem involving a wide...