OTEC, 140 years old technology


A UK-based startup, Global OTEC, is throwing its hat in the ring to revolutionize energy for tropical island nations with a century-old technology, Ocean Thermal Energy Conversion (OTEC).

The company presented advanced concepts for Dominique, its next-generation platform capable of generating 1.5MW, at the International Vienna Energy and Climate Forum (IVECF) in Austria last week.

Conceived in 1881 by French physicist Jacques Arsene d’Arsonval, OTEC harnesses heat from surface water, heats fluids with a low-boiling point, and uses the ensuing steam to drive turbines and thus generate electricity.

Unlike many other forms of renewable energy, OTEC is capable of running 24/7 and generating electricity at a consistent rate.

Navigating Challenges

While its potential is immense, technological barriers, insufficient funding, and the rise of cheaper renewable alternatives have hindered OTEC’s progress.

Currently, only two OTEC plants function globally— small demonstration plants in Hawaii and Japan— and their contribution accounts for a meager 100kW each to the grid, according to reports in TNW.

OTEC’s biggest challenge stifling its large-scale adoption has been the monumental costs involved in setting up plants, a major chunk of which is accounted for by the expensive long pipes fixed to the seabed mandatory to transport water from the plant.

Global OTEC has seemingly found a solution to this problem.

Aimed to provide small island nations with a clean, baseload energy alternative to diesel, the company has designed its commercial-scale OTEC flagship plant, Dominique, to be modular and cost-effective with a floating barge design.

CEO and founder Dan Grech told TNW that their design would only require a single 750-meter-long cold-water pipe, estimating costs to be roughly between $2.5 and $3 million, significantly less than other OTEC plants.

“History is an important teacher, and we are committed to learning from it,“ said Grech.

Dominique—paving a sustainable future

Recently unveiled at IVECF, Dominique is set to be installed in São Tomé and Príncipe. The project has received Approval in Principle (AIP) from Lloyds Register and is closer to viability.

As Dominique progresses through geotechnical surveys and detailed designs, Global OTEC aims to start commissioning by the end of 2025.

“We know Dominique is a life-changer for small islands and coastal nations, and that’s why we see the pace of the project on track for success,” Grech said in a statement.

“This is an important lesson we want to share with investors as the public-private partnership allowed the smooth undertaking of critical techno-economic, environmental, and social studies to progress to this point,” he added.

Gabriel Mquengo, the National Energy Director of the Directorate General of Natural Resources and Energy (DGRNE) of the Ministry of Infrastructure, Natural Resources and Environment of São Tomé and Príncipe (MIRNMA), recognized the technology as a life-changing opportunity.

“OTEC is a new opportunity for São Tomé and Príncipe to explore renewable energy, meeting the national ambitions and goals of the National Determined Contributions,” he highlighted.

Dominique has the potential to decarbonize 10 GW of installed diesel capacity across 32 island countries, and the company believes that developing partnerships with these countries will secure clean and sustainable energy, leveraging the vast, untapped technology that is OTEC.