Gulf-Stream-Based, Ocean-Thermal Power Plants

This paper presents the results of an ongoing analytical study at the Univ. of Mass, for the design of major components and a total power system for Gulf-Stream-based ocean-thermal power of 400 Megawatts electrical net power output. On the basis of these studies, the ultimate power potential of a 15 mile wide by 550 miles long length of the Gulf-Stream extending from south of Miami, Fla. to Charleston, S.C. is estimated to be approximately 2 trillion kilowatt hours per year which could be transmitted to shore by undersea cables. Critical subsystems and components (such as heat exchangers, ocean-based hulls, and cold water inlet pipe) are identified, and the technical basis for their configuration and design is discussed. 90/10 copper-nickel alloy plate-fin heat exchangers, with propane flowing upward (evaporators) or downward (condensers) through small passages in the plates and sea water flowing horizontally between the plates, have been selected. The latest power system (Mark II) is based on a submerged, twin catamaran concrete hull configuration with hulls approximately 80 ft in diameter by 800 ft long. The evaporators are staggered serially in height in 6 tiers placed above the twin hulls which contain the condensers, turbines, pump, and other power cycle components. A cold-water inlet pipe of elliptical cross section (1500 ft long and with a hydraulic diameter of 87 ft) is hinged between the hulls with a gun-buckler type joint. Technical problems facing the deployment of such plants are summarized, and the latest cost estimates predict busbar power costs of approximately 15 mills per kilowatt hour.