The study presents an illustrative data base for estimating environmental effluents from alternative technologies for thermally generated electrical power. The data are to illustrate characteristics and possible magnitude of effluents to various environmental media and to illustrate the effect of choices of technology on the media effluents. The entire fuel cycle for each alternate technology is examined, representative sources of environmental effluents at each step in the fuel cycle are identified, and material and environmental quantities are indicated on a representative flow sheet for each means of generating electric power: (1) Light-water nuclear reactor; (2) Low-sulfur bituminous coal; (3) Residual fuel oil; (4) Natural gas; (5) High-sulfur coal, with coal gassification and sulfur removal; (6) High-sulfur coal, with SO2 recovery by wet-limestone scrubbing; (7) Geothermal steam; (8) Breeder fission reactor; (9) Solar energy; (10) Thermonuclear fusion.