(94e) Technical and Economic Analysis of Hydrogen Production by Ocean Thermal Energy Conversion

The National Hydrogen Roadmap highlights the development of advanced renewable energy methods that do not emit carbon dioxide. The world's oceans are the largest collector and storage of solar energy and have an enormous potential to supply the growing worldwide energy demand. The general perception is that ocean energy is limited to only tropical countries; therefore, the full potential of ocean energy for at-sea production of ammonia as the hydrogen carrier and desalinated water production has not been adequately evaluated. This study presents an updated analysis that shows the technical and economic viability of the ocean thermal energy conversion (OTEC) plantships. This study is based on a detailed plantship design performed in 1980 by The Johns Hopkins University Applied Physics Laboratory in collaboration with industrial partners. This design has been fitted with an updated power system based on compact heat exchangers that have a 25+ year proven manufacturability and performance history. The analysis shows promising favorable economics for at-sea production by OTEC plantships of anhydrous ammonia as the hydrogen carrier with an additional co-product of desalinated water for potable consumption. A DOE study (Potential Role of Ammonia in a Hydrogen Economy, February 2006) concluded that ?Ammonia may be considered as a potential hydrogen carrier for hydrogen delivery and off-board storage, such as refueling stations and for stationary power applications.? The potential use of ammonia as the hydrogen delivery systems is further supported bythe established surface and ocean transportation systems for delivering these two energy and water commodities to the coastal states of the United States, with a further, enormous potential for the world market. Achieving this goal of ammonia-based distributed power generation may take some time; however, there is significant near-term market opportunity for hydrogen derived from renewable non-carbon sources in petrochemical and refining industries in California and the Gulf of Mexico States.