The vast expanse of tropical oceans holds an extraordinary energy potential, with the ability to supply the world’s daily electricity by harnessing just a fraction of the solar energy they absorb. Ocean Thermal Energy Conversion (OTEC) emerges as a promising method, tapping into the temperature disparity between the warm surface and the cold depths.
OTEC’s roots trace back 142 years, with the first trial in 1881 and a 22-kilowatt plant in Cuba in 1930. The basic principle involves locating an area with a substantial temperature differential, typically in the tropics, where warm surface water meets cold water at depth. A floating barge with a closed-loop power system utilizes a refrigerant-style liquid to generate electricity. Despite its potential, historically, OTEC has faced efficiency challenges, with most of the power generated being consumed by the pumps, bringing cold water to the surface.
Global OTEC, a London-based company, has introduced the Dominique barge, anticipating commissioning in 2025 off the coast of São Tomé and Príncipe. Designed to provide a net output of 1.5 megawatts year-round, it is hailed as the “first commercial-scale OTEC platform.” However, hurdles abound, ranging from the impact of storms on floating barges to biofouling and the corrosive nature of seawater.
Economically, OTEC faces an uphill battle, grappling with the Innovation Valley of Death, as described by Ocean Thermal Energy Corporation. The infrastructure costs and the harsh marine environment have hindered its commercial implementation. While the Dominique barge aims to deliver power at a Levelized Cost of Energy (LCoE) between $150-300 per megawatt-hour, OTEC’s long-term viability is questioned. The company envisions larger-scale plants reducing costs to as low as $50/MWh, potentially aligning with wind and solar prices.
Ambitious projects, such as the NEMO project in Martinique, faced technical difficulties and funding challenges, casting shadows on the feasibility of scaling up OTEC. Despite the enormous potential highlighted in a 2021 review, the harsh realities of high costs and corrosive marine environments impede widespread adoption.
Global OTEC’s Dominique barge stands as a beacon of hope. Yet, the journey to harnessing the vast energy potential of tropical oceans remains a long shot, requiring concerted efforts and technological advancements.
Source: Global OTEC