Over the past few years, the U.S. Department of Energy (DOE) has invested several million dollars toward commercializing ocean thermal energy conversion (OTEC) technology, a process of generating energy by harnessing the temperature differences in the world’s oceans. Security giant Lockheed Martin has been especially active in pioneering research and development in this field. In 2010, a Lockheed Martin-led industry team designed and developed “critical system components” for an OTEC pilot plant in Hawaii, intended to provide power for both the local community and the nearby naval base.
Now, a breakthrough material developed through Lockheed Martin’s Open Innovation program could improve the performance and lower the cost of building a commercial scale OTEC power plant. Researchers led by James Klett at Oak Ridge National Laboratory’s Materials Science and Technology Division have developed a graphite-foam-based heat exchanger that they say is twice as effective as existing heat exchanger technology.
With a higher surface area, the graphite-foam material could cut the size of OTEC facilities in half, allowing a commercial-scale plant to fit on a standard size offshore platform. This technology, the researchers claim, could reduce the capital cost of a 1-megawatt OTEC plant by half.
The U.S. military sees OTEC as having a high potential to meet energy needs in parts of the world where long supply lines or sparse infrastructure make pose difficulties to securing reliable power. Unlike solar and wind power, OTEC can generate energy 24 hours a day. Estimates suggest that, in tropical latitudes, OTEC has the potential to generate 3 to 5 terawatts of power without affecting the temperature of the ocean. Klett and his partners at Lockheed Martin are building a laboratory-scale prototype of their graphite-foam heat exchanger to test at the National Energy Laboratory of Hawaii Authority. The pilot project is scheduled to begin this winter.