Japanese Shipbuilder Granted AIP for Development of OTEC

Japan Marine United Corporation (JMU), a development-oriented shipbuilder, has been granted the Approval in Principle (AIP) by Nippon Kaiji Kyokai (a Japanese ship classification society, known as ClassNK) on September 2, 2013, for its development of the submersible floating structure of ocean thermal energy conversion (OTEC). This is the first time that such a certification has been issued for a submersible type.

In cooperation with Saga University, JMU has created a conceptual design of a 10-megawatt-class OTEC. This design is based on the performance of a submersible ocean nutrient enhancer "TAKUMI," which pumped up to 100,000 tons of deep ocean water per day when hit by five typhoons during sea experiments.

OTEC uses the temperature difference between warm surface water and cold deep sea water to generate electricity. A work medium such as ammonia is vaporized by the warm surface water to drive a turbine. In turn, it is then cooled to a liquid state by the cold deep water and is recirculated back to the vaporizer.

JMU aims to develop and demonstrate an element technology for a heat exchanger and heat cycle in order to achieve a power generation of 20 yen (20 U.S. cents) per kilowatt-hour or less in the future.