Ocean thermal energy nears commercial viability

Ocean thermal energy conversion (OTEC), a technology that generates power by exploiting thermal layers in the ocean, will soon be deployed to power island nations, according to UK-based company Global OTEC.

With OTEC technology, surface water heated by the sun is pumped through an evaporator containing a working fluid, with the vapour driving a generator. Cooled water pumped from deeper in the ocean is then used to condense the liquid.

Global OTEC has addressed issues with accessing the colder deepwater layers by designing a floating power generation platform to operate around 10 kilometres offshore. Electricity would be carried from the platform to shore via cable.

A report published Tuesday by New Scientist cited clean energy experts as describing previous attempts to deploy OTEC as “disappointing.” However, advances in the technology have brought the approach closer to viability, particularly for tropical island nations relying on relatively expensive imported diesel, they said.

Compared to a technology like solar PV, OTEC installations would have the added benefit of keeping limited land space free for other uses.

Global OTEC plans to install a 1.5-MW platform off the West African island nation of São Tomé and Príncipe by 2026. CEO Dan Grech told New Scientist the company is in talks with officials in other countries, such as Fiji.

“OTEC will be part of providing an equitable energy transition so these places aren’t depending on diesel imports from the richest petrol states in the world,” he said.

Photos via Global OTEC