A summary is presented of the research programs in the U.S. that have studied the utilization of reject heat from both fossil and nuclear power plants. The results of over 80 investigators are presented in two areas. The first area is soil warming, greenhouses, and warm water irrigation. The second area is aquaculture and integrated systems. The present status of this research indicates that technical feasibility for the utilization of reject heat is at hand. Many problems, such as institutional, regulations, land use, and the coupling of heat source to heat utilization systems exist.