The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshall T. Savage is a book (published in 1992) in the field of Exploratory engineering that gives a series of concrete stages the author believes will lead to interstellar colonization.
Step two was build seasteads powered by Ocean Thermal Energy Conversion (OTEC) power.
The U.S. Naval Facilities Engineering Command awarded Lockheed Martin a $4.4 million contract modification to advance the design for an Ocean Thermal Energy Conversion (OTEC) pilot plant off the coast of Hawaii. The Hawaii pilot plant is expected to have a 10 megawatt capacity, and be operational by 2012 or 2013. It is hoped that its success will lead to commercial-sized plants generating 100 MW or better, by 2015.
Ocean thermal energy conversion (OTEC) uses the temperature difference that exists between deep and shallow waters to run a heat engine. As with any heat engine, the greatest efficiency and power is produced with the largest temperature difference
Earlier OTEC systems had an overall efficiency of only 1 to 3% (the theoretical maximum efficiency lies between 6 and 7%). Current designs under review will operate closer to the theoretical maximum efficiency. The energy carrier, seawater, is free, though it has an access cost associated with the pumping materials and pump energy costs. Although an OTEC plant operates at a low overall efficiency, it can be configured to operate continuously as a Base load power generation system. Any thorough cost-benefit analysis should include these factors to provide an accurate assessment of performance, efficiency, operational, construction costs, and returns on investment.
India piloted a 1-MW floating OTEC plant near Tamil Nadu.