A few years ago, Lockheed Martin was working to build a pilot plant to demonstrate a renewable energy technology called ocean thermal energy conversion near the Hawaiian island of Oahu. They wanted to get funding from the U.S. Navy for the project and to cable the electricity straight to the naval base at Pearl Harbor.
Now Lockheed is designing that 10-megawatt pilot plant, but not in American waters. Instead, the facility will be off the coast of southern China, and Lockheed’s customer is a private Chinese company that develops resorts and luxury housing.
Over the years Lockheed has approached various potential partners, says Rob Varley, the company’s OTEC project manager.
Building an offshore energy station at commercial scale is an expensive proposition, particularly when it’s the first time the technology is being tried out. Lockheed won’t release the cost of the project, but outside experts estimate that a 10-MW facility would cost roughly US $300 million to $500 million.
However, experts say that a full-scale 100-MW plant would be more competitive at just $1.2 billion.
“The biggest challenge has been to get the gold and start the project,” says Varley, but in terms of engineering, he says, “I don’t see any showstoppers at this point.”
That’s not surprising, since the company has been working on OTEC since the 1970s, and the technology hasn’t changed drastically since then. OTEC systems make use of the temperature differential in tropical areas between warm surface water and cold deep water. In most systems, ammonia, which has a very low boiling point, passes through a heat exchanger containing the warm water.
The ammonia is vaporized and used to turn a turbine, and then it’s cycled past the cold water to recondense. This is a renewable energy technology with the rare capacity to supply base-load power, as water temperatures are fairly stable.