Ocean thermal energy conversion (OTEC), a term with which Is- landers are becoming fa- miliar through recent news stories, can be de- scribed simply as solar energy from the sea.
As with many other simple-sounding defini- tions, the process of put- ting concept into practice is not simple.
The announcements within the last few days of a floating test platform (OTEC-1) and a Seacoast Test Facility for Keahole Point, Kona, on the Big Is- land, are for projects aimed at working out the complex technology to make OTEC practical.
A fact sheet issued in May by the U.S. Depart- ment of Energy describes the advantages and dis- advantages, the technol- ogy and the potentials of ocean thermal energy conversion.
First, the advantages.
The major advantage of OTEC is that it’s a re- newable energy resource that uses no fuel. The ocean itself collects and stores solar radiation as thermal energy, so there is no need to build a col- lector or energy storage system.
OTEC plants could op- erate 24 hours a day, as contrasted with some other solar electric sys- tems that might be lim- ited by amount of sunshine.
Critics say OTEC plants operate at low thermody- namic efficiency. That’s the ratio of work output to heat energy input in a heat-engine cycle. …
But OTEC proponents say the controlling factor is not thermodynamic ef- ficiency but energy cost. Since no fuel is required, even with a low net effi- ciency, OTEC plants may be able to produce elec- tricity as a cost compara- ble to that of electricity derived from coal, nu- clear power, or land- based solar plants by the end of the century. …
Both of the two Kea- hole facilities, the floating test platform and the Sea- coast Test Facility, will be used for experiments to inhibit or remove corro- sion and “biofouling,” the buildup of marine organ- isms on tube surfaces that reduce heat transfer efficiency.
The Seacoast Test Fa- cility “for the first time will give us a real feel of the importance of corro- sion and biofouling — two critical factors to OTEC operations,” said Joseph Draley of the De- partment of Energy’s Ar- gonne National Laboratory.
