The Johns Hopkins University Applied Physics Laboratory, under contracts with several agencies of the federal government and an agency of the State of Maryland, is engaged in developing energy resources, utilization concepts, and monitoring and storage methods. This Quarterly Report summarizes the work on the various tasks as of 31 March 1980. The Energy Quarterly Report is divided into four sections. The first, Geothermal Energy Development Planning and Technical Assistance, supported by the Department of Energy/Division of Geothermal Energy (DOE/DGE), contains reports on the progress of geothermal-related tasks on which effort was concentrated during the quarter. The second section, Operational Research, Hydroelectric Power Development, supported by the Department of Energy/Resource Applications (DOE/DGE), contains reports on small-scale hydroelectric investigations in the southeastern states. The third section, Seismotectonic Investigation, supported by the Reactor Safety Research Division of the Nuclear Regulatory Commission, reports on a neotectonic investigation in Connecticut. The fourth section, Energy Conversion and Storage Techniques, contains two articles, the first on OTEC core unit testing supported by the Department of Energy/Division of Central Solar Technology (DOE/CST), and the second on an analysis of the Community Annual Storage Energy System at the U.S. Naval Air Station, Norfolk, Va. This work is supported by the Department of Energy and the Department of Defense, Naval Facilities Engineering Command/Atlantic Division.