Energy conservation is not typically considered a part of national security strategy. However, many of the conflicts around the world have been linked to the competition for natural resources.
Federal spending on Department of Energy energy conservation activities pales in comparison with other parts of the federal budget. Currently, energy conservation is less than one billion dollars, or less than five-tenths of a percent of the budget. Historically, energy conservation spending was much higher in the late 1970s when the Carter Administration pushed a number of energy-saving initiatives.
Source: Office of Management and Budget, Budget of the U.S. Government, FY2007, Historical Tables [1].
Links:
[1] http://www.whitehouse.gov/omb/budget/fy2007/