Makai Ocean Engineering Inc. has built an ocean thermal-energy conversion demonstration plant in Hawaii.
The 105-kilowatt project that cost about $5 million to construct is the world’s largest plant to date utilizing the evolving renewable source. It was funded by the U.S. Navy’s Office of Naval Research, Hawaii Natural Energy Institute and Makai.
The ocean thermal-energy industry is in the research stage and yet to reach commercial scale. Electricity from it is generated from the differences in temperature of warm surface water and colder depths that can be used to drive a turbine. Ocean thermal-energy produces baseload power, a steady stream of electricity similar to a fossil-fuel powered plant.
“The plant is dispatchable, meaning the power can be ramped up and down quickly to accommodate fluctuating demand and intermittent power surges from solar and wind farms,” Duke Hartman, vice president of business development at Kailua, Hawaii-based Makai, said in a phone interview.
In time, “we think that ocean thermal-energy will be an important element of creating a stable grid with renewable energy,” he said Thursday.
The Navy is investing in the project because it has a target for 50 percent of its shore-based energy to come from alternative sources in five years. The state of Hawaii hopes to be wholly powered by renewables by 2045.
“The biggest challenge to the industry is the economics and the financing,” Hartman said.
Makai recently signed a memorandum of understanding to construct a 1-megawatt ocean thermal-energy plant with Japanese companies including Xenesys Inc., Yokogawa Electric Corp., Kobe Steel Ltd. and Japan Marine Ltd. Saga University on the island of Kyushu in Japan will also be involved.
Countries with the potential to be powered by ocean thermal-energy include Brazil, Sri Lanka, the Maldives and West African nations, according to Hartman. “Anywhere tropical with deep water is ideal, especially if they import their fuel.”
The demonstration plant on the Big Island in Hawaii is connected to the grid and generates enough electricity to power 120 homes. Hartman estimates a 100-megawatt ocean thermal project could sell electricity at 20 cents per kilowatt-hour.
“We need a visionary investor to get us past the expensive pilot project into the large-scale commercial projects,” he said.