Between 1972 and 1976, the rate of energy consumption decreased substantially because of supply disruptions, a recession, and increased prices. However, many conservation measures taken during this period have not been sustained; 1978 statistics show that the Nation's energy consumption is increasing. The administration has proposed a national energy plan which highlights conservation. However, GAO previously reported that these provisions would not significantly reduce energy demand. The Department of Energy should continuously assess each Federal initiative for what its contribution will be in meeting energy objectives for both the long and short term. It also should develop sufficient standby measures to implement in case ongoing programs do not result in meeting the established goals. GAO recommends that Congress equalize the Federal share of costs for mass transit projects undertaken with Highway Trust Fund moneys. Congress should also specifically include heat pumps as approved energy conservation measures eligible for residential tax credits. Other recommendations concern transportation energy use and industrial, residential, and commercial energy consumption. Tables and footnotes are included. Sources contacted during the review and two related letters are appended. A list of abbreviations is provided. (Author abstract modified)