Potential energy resources of the world are surveyed, and U.S. energy reserves from fossil fuels and nonbreeder nuclear fission fuel are discussed. With petroleum and natural gas being rapidly depleted, the role that products from gasification and liquefaction of coal and oil shale will contribute is examined. The U.S. has over 50 nuclear power plants that supply about 7.5 percent of electrical power production presently; projections show 200 such plants in operation to supply 35 percent by 1985 and over 1000 by the year 2000 to supply over 60 percent. Geothermal energy is presently supplying economical production of electricity, process heat, and agricultural and space heating; in twenty years the amount of geothermal energy being used will depend on the way it is developed and on the costs of alternatives. Combined with energy conservation measures, solar energy can supply up to 50 percent of the energy needs by the year 2000. The potential of each method for nuclear fusion--magnetic confinement and laser-produced--is summarized briefly. (ERA citation 01:016337)