First published in Cleantech magazine, Volume 6, Issue 3. Copyright Cleantech Investor Ltd

In tropical regions, the difference in temperature between warm surface ocean waters and the depths beneath can be very great.  Scientists at Hawaii’s HNEI, working with defence and technology company Lockheed Martin, want to take advantage of this fact to generate electricity and drinking water. They are among the few world experts on ocean thermal energy, whose exploitation depends on a difference of at least 20°C in sea temperatures and essentially converts solar radiation to electric power.  Helped by HNEI, Lockheed Martin intends to build a 5-10MW pilot plant off the island of Oahu. 

While Lockheed Martin and its partners improve efficiency and other issues, expertise cultivated in Hawaii is also being used further east, in the Atlantic.  In the Bahamas, Jeremy Feakins, CEO of the Ocean Thermal Energy Corporation (OTEC), is driving the construction of what could be the world’s first commercial plant. Rather than acting as a research company, OTEC runs on a build-own-operate model. With the aim of building a plant, the company has signed a Memorandum of Understanding (MOU) with utility Bahamas Electricity Corporation to complete the design process expected to lead to the company building, owning and operating two commercially viable ocean thermal energy plants.  The company says it expects to obtain MOUs and Power Purchase Agreements with a total of eight major customers within two years.

Nevertheless, Feakins admits utilities have dithered.  They are, he points out, risk averse:  “No-one wants to have the first commercial OTEC plant,” he says.  The problem, he concedes, is less about getting the plant to work than about getting people on board.  According to Feakins: “This is not so much a technology challenge as a ‘ramping it up’ challenge”. That includes a whole range of issues, from persuading utility managers to passing environmental impact assessments and planning restrictions.  But Feakins is convinced that the projects will become attractive due to raw economics. 

The plant becomes viable when oil prices are at $60/barrel, while power companies charging the high electricity prices typical of island economies will be more likely to consider this alternative technology – particularly if, as in this case, it also drives a desalination unit which would otherwise be powered by fossil fuel.  “We hope to start building an OTEC plant in 2013 and have it running from 2014/15,” states Feakins. 

See also: Aloha Carbon Footprint - Hawaii: Natural hub for US cleantech