Renewable energy sources are the go-to these days, as the world pushes hard to lower carbon emissions and mitigate climate change. One renewable energy source in particular has not been explored as much, with many deeming it a myth. Now, a UK-based company is set to deploy a floating platform off the coast of Africa to harness it, backed by international support. It’s officially a new era.
A brief overview of this renewable energy concept
You may have heard of hydro-energy and of geothermal energy, but have you heard of ocean thermal energy? It’s not a new concept, but much of it remains unknown. The concept is simple. The ocean has a low albedo, which is a surface’s ability to reflect sunlight. Now, sunlight hits the ocean surface, and 94% of the UV radiation is absorbed. The UV radiation excites the surface water molecules, creating a rise in surface temperature.
As the surface is heated, the ocean depths remain cold, which results in a temperature gradient. This temperature gradient can be utilized to power turbines, converting ocean thermal energy into electricity. So many of you might think, ‘Why haven’t we tapped into this source before?’
The fact is, many have tried before. According to AZoCleantech, French physicist Jacques-Arsène d’Arsonval first proposed the concept in 1881; however, technology was limited, so it remained a concept. In 1930, Georges Claude, d’Arsonval’s pupil, engineered an energy conversion plant in Cuba. In 1935, he engineered a second phase plant off the coast of Brazil, which was unfortunately destroyed by storms before it was economically feasible. Since then, funding has been a major problem, but now it could all change, as interest in this over-140-year-old concept is finally gaining momentum.
Ocean thermal energy conversion comes to São Tomé and Príncipe
Not only has ocean thermal energy conversion (OTEC) been proven to generate continuous power, but it also generates fresh drinking water and cold water for refrigeration. Since Claude’s prototype in 1930, only a small number of OTEC plants have existed globally, in countries such as the USA, Japan, and Korea, though none have been floating platforms deployed in a developing small island state.
Global OTEC Resources, a UK-based company, is going to deploy a 1.5 MW floating OTEC platform, called the Dominique, in the African island nation of São Tomé and Príncipe by 2025. The United Nations Industrial Development Organisation (UNIDO) has provided its support through a Green Climate Fund financed project to safeguard the development of the Dominique. The company obtained its certificate of approval for the installation methods of a cold-water riser. A cold-water riser is essentially a pipe that transports seawater from the sea to a seawater tank and back from an offshore OTEC platform.
“History is an important teacher, and we are committed to learning from it. Failure of previous OTEC projects highlights where we should exercise caution, so third-party technical due diligence from the earliest stage is important for our success.” – Global OTEC Founder and CEO Dan Grech
Expanding knowledge on ocean thermal energy
A pan-European trust, called PLOTEC, consists of Austria, Italy, Portugal, Spain, and the United Kingdom. PLOTEC is also presently busy with a project comprising the design and validation of an OTEC platform that can resist extreme weather conditions in tropical oceans, using a feasible cost model validated by a smaller prototype. The goal of the project is to gain and exchange knowledge regarding ocean thermal energy and its conversion, as well as to create more awareness of the concept.
“Since the ocean comprises around 70% of the earth’s surface it is a vast receiver and repository of solar energy. While waves, winds, tides, and currents are all forms of ocean renewable energy, which vary with time and season, conversely, an OTEC system permits the generation of constant power 24 hours a day, 365 days a year.” – International Energy Agency’s (IEA’s) Ocean Energy Systems (OES) technology collaboration program
Water and solar energy have gone hand-in-hand with many other power-generating designs as well. Hopefully, ocean thermal energy will become more popular as we gain more knowledge.
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