Summary: Energy is an operational necessity as it is a foundational enabler for all military capabilities. Army operations span a diverse range of environments and tasks, from base infrastructure under lesser threat, to expeditionary operations and sustained campaigns in hostile areas. Supplying energy to these diverse missions is increasingly challenging. Constraints and threats to the supply of energy are growing in scope and complexity both abroad and at home. To address these challenges the Army is implementing a comprehensive Energy and Sustainability program based on culture change, increased energy efficiency, and development of renewable and alternate sources of energy. The Army is making these investments to ensure the Army of tomorrow has the same or greater access to energy as the Army of today.