Ocean Thermal Energy Conversion

OTEC pilot plant

10 megawatt pilot plant illustrated off Kahe Point, Oahu.

Ocean Thermal Energy Conversion (OTEC) is a process that can produce electricity by using the temperature difference between deep cold ocean water and warm tropical surface waters. OTEC plants pump large quantities of deep cold seawater and surface seawater to run a power cycle and produce electricity. OTEC is firm power (24/7), a clean energy source, environmentally sustainable and capable of providing massive levels of energy.

OTEC has long been challenged by high capital costs in a world of cheap energy. Recently, however, higher electricity costs, increased concerns for global warming, and a political commitment to energy security have made initial OTEC commercialization economically attractive in tropical island communities where a high percentage of electricity production is oil based. Even within the US, this island market is very large; globally it is many times larger. As OTEC technology matures, it should become economically attractive in the southeast US.

Makai has been pioneering OTEC research since working on the first net-power producing plant in 1979. Since that time, Makai has been a sub- or prime contractor for dozens of unique research and development contracts in OTEC. Most recently, Makai has been involved with Lockheed Martin and others pursuing the development of 100MW OTEC plants for island communities like Hawaii and Guam.

Makai has developed internationally recognized expertise in OTEC in the areas of commercial and pilot plant designs, overall technical and economic modeling, heat exchanger design and testing, cold water pipe design and deployment, environmental effects (hydro- and bio-plume modeling), and the power cable to shore.

Current Projects:

  • OTEC Demonstration Plant: Marine corrosion research and heat exchanger performance testing in a complete OTEC cycle using surface (warm) and deep (cold) seawater flows.
  • Turbine: Installing a turbine on Makai’s heat exchanger test facility to become the only operational OTEC power plant using deep cold water in the United States. This project involves designing, testing, and optimizing the OTEC power system and seawater and ammonia flow controls.
  • Pipelines: Ongoing cold water pipe research and design.
  • Pilot Plant: Designs for the first offshore OTEC pilot plant in the range of 2 – 10MW net-power.
  • Environmental Effects: Multiple discharge water hydro- and bio-plume studies.