Fri | Jun 2, 2023

Dan Grech | How ocean energy can transform the power generation in the Caribbean

Published:Monday | April 3, 2023 | 10:22 AM
Dan Grech
Dan Grech
The Galleon Beach in St Elizabeth. Dan Grech writes, having the ocean as their largest natural resource, more than 44 million Caribbean people can benefit immensely from its use as a source of power.
The Galleon Beach in St Elizabeth. Dan Grech writes, having the ocean as their largest natural resource, more than 44 million Caribbean people can benefit immensely from its use as a source of power.

With the recent signing of the High Seas Treaty, which aims to help place 30 per cent of the ocean into protected areas by 2030, the ocean is finally starting to receive the attention it very much needs. The agreement between the countries of the United Nations, signed at the beginning of March in New York, will also put more money into marine conservation and establish new rules for mining at sea, helping reverse biodiversity losses and ensure green development. This is a milestone for protecting the oceans, and there is yet more to explore sustainably when it comes to the seawater potential. One area, in particular, that has been neglected for decades is ocean energy.

The most abundant form of energy on Earth is heat, and most of it is stored in the upper layers of our ocean across the equatorial regions. During an average day, the 60 million square kilometres on the surface of tropical seawater absorb one quadrillion megajoules of solar energy, that is not being harnessed. To release the same amount of energy through fossil fuels, we would need to burn 170 billion barrels of oil, an unthinkable economic cost for tropical islands and terrible for our environment.

Having the ocean as their largest natural resource, more than 44 million Caribbean people can benefit immensely from its use as a source of power. A technology of significant interest is Ocean Thermal Energy Conversion (OTEC), which can use the ocean like a battery to harness this untapped wealth to create renewable electricity. It uses solar heat energy absorbed by the ocean and has no need for oil, gas or coal. OTEC can decrease costs and stabilise the price of electricity, reducing the frequency of blackouts and preventing economic shocks from political events while helping small island nations meet several UN’s Sustainable Development Goals (SDGs).


Electricity prices in the Caribbean average around US$0.25 per kWh, with some countries reaching over US$0.40 per kWh. According to data from the World Bank, out of 11 Caribbean countries with available information, nine generated more than 80 per cent of their electricity using imported fuels and five imported 90 per cent of their energy. As oil prices continue to increase, the situation is reaching a breaking point.

Diesel is expensive, environmentally harmful and weakens the energy security of nations dependent on it. Conventional renewables alone – such as solar, wind and hydro – do not provide the complete answer for the specificities of tropical islands. For example, solar requires land and is intermittent as wind, while hydroelectricity can be disrupted by droughts – which are increasing in our changing climate. OTEC requires one-tenth of the space needed by solar plants, preventing deforestation and soil erosion using floating offshore barges. This saves habitats, mitigates the impacts of climate change and does not compete with agriculture and public infrastructure.

Island communities must not be left behind in the energy transition, remaining dependent on diesel imports and options that do not offer the much-needed 24/7 year-round baseload power. Paying four times more for electricity than rich nations such as the United States, Caribbean people urgently need a sustainable source of energy that can unleash economic growth and prosperity for the entire region. By halving diesel costs ocean energy can give islands a stable, 30-year price point for electricity generation. It can also free up funding that is spent subsidising fossil fuels for more urgent climate mitigation and adaptation projects, and investment in education and health, for example.


With its tropical climate and large ocean surface area, Jamaica is well suited for OTEC, which can replace the current 89 per cent of the energy that is generated by fossil fuels. Furthermore, OTEC can diversify and increase the country’s renewable energy capacity and cut off the share of GDP spent on fuel imports (7.4 per cent). Previous studies in the 1980s looked at Kingston, Negril, Lucea, Port Maria and Port Antonio as potential areas for OTEC implementation. Although they didn’t progress at the time, ocean energy has been continuously developed and proven in other parts of the world. Since 2015 working plants in Hawaii and Japan have come online, and in 2025 a new OTEC platform will be installed by Global OTEC in the African island nation of Sao Tome and Principe.

OTEC can help tropical island nations reduce long-term energy costs, generate employment, reduce trade imbalances from fuel imports and face the challenges arising from climate change. And all of that while also having a positive impact on the ocean, as processed seawater can produce other useful by-products, such as freshwater, lithium and hydrogen. The OTEC process can also upwell plankton for more productive fisheries and cool the seawater to prevent the further disappearance of pelagic fish in our warming climate.

The current developments on OTEC technology are also considering particular weather conditions, such as high-risk tropical storms common in the Caribbean. Through the project PLOTEC, a pan-European consortium, an OTEC platform capable of withstanding the extreme weather effects of tropical oceans is being developed with a viable cost model and validated by a scaled demonstration of a structure. This will lead to a more resistant OTEC system, making it an advantage when compared to other renewable energy systems that can be more easily damaged by storms and hurricanes. This way, OTEC stands out as a solution for power generation for tropical island nations.

Dan Grech is the Founder and CEO at Global OTEC. He has consulted on Caribbean Island energy policies and formed Global OTEC’s partnership with SIDS DOCK, an UN-recognised international organisation representing 32 small islands and low-lying developing states across the globe for addressing climate change, resilience and energy security. Send feedback to