The Energy Independence and Security Act of 2007 (EISA) requires Federal agencies to apply energy efficiency measures to Federal buildings so that by Fiscal Year (FY) 2015, each agency's energy intensity is reduced by 30 percent from the baseline established in FY 2003. Energy intensity is calculated as the energy consumption in British Thermal Units (BTUs) per gross square foot of the Federal buildings. The Department of Energy's (Department) FY 2003 energy consumption baseline for its sites around the Nation was 23 trillion BTUs, supplied by energy acquired at an annual cost of around $229 million. If the Department achieves the 30 percent energy conservation requirement in FY 2015, its energy consumption would be reduced by nearly 7 trillion BTUs, resulting in a savings of nearly $80 million annually. This equates to the power necessary to operate nearly 180,000 housing units.