The federal government has a number of policy tools available to encourage the development and deployment of innovative clean energy technologies. Some of these policy tools include: clean energy mandates, carbon taxes, carbon cap and trade, environmental regulations, loan guarantees, grants, and tax expenditures. In 2005 and 2009, Congress passed legislation that provided loan guarantee authority to the Department of Energy (DOE) for innovative clean energy technologies and clean energy projects. In 2011, the high-profile bankruptcy, and subsequent loan default, of Solyndra resulted in a congressional investigation and subjected DOE's loan guarantee program to a high degree of scrutiny. This book provides analysis of goals for and concerns about the use of loan guarantees as a mechanism to support the deployment of innovative clean energy technologies.