Recoral
Growing corals on offshore wind turbines
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With our ReCoral project, we aim to support natural coral growth on the foundations of offshore wind turbines on our Greater Changhua offshore wind farms in Taiwan. If successful, we hope to scale up this coral restoration method to use on other offshore wind farms with similar ecology. ReCoral is a proof-of-concept trial in partnership with the Penghu Fishery Research Center – a research institution specialised in aquaculture and marine biology, under the Taiwan Ministry of Agriculture.
Our non-invasive method involves collecting coral spawn that washes up on the shoreline of the Penghu Islands, cultivating it in the laboratory, transferring viable corals to customised metal frames, and then introducing them to designated locations on turbine foundations, with the intention that they will settle and grow there.
Corals live in symbiosis with an algae called zooxanthellae that relies on sunlight for photosynthesis, meaning they must live near the surface.
But these algae can be badly harmed if the water becomes too warm, too polluted, or too often exposed by extreme low tides, resulting in coral bleaching. As the impacts of climate change accelerate, coral bleaching occurs more and more frequently in the shallow waters where corals live naturally.
On the turbine foundation, by contrast, the corals will have good access to light while being protected from extreme temperatures by the natural circulation of the cooler, deeper water the turbines stand in. Living further out to sea, the corals are also protected from frequent human disturbance.
In practice, there are many challenges to overcome if corals are to make their home on offshore wind turbine foundations. ReCoral is an experiment grounded in laboratory-based trials and meticulous planning. The method needs to be tested and refined, and its impact measured and reported.
According to the International Union for Conservation of Nature, more than 500 million people around the world depend on coral reefs for food, storm protection, jobs, and recreation.
As a leading renewable energy company, we’ve made the fight against climate change our core business through the deployment of green energy solutions.
But we want these solutions to do more than generate green energy. We’ve set the ambition to achieve a net-positive impact on biodiversity for every new project we commission from 2030 onwards.
Our method begins on the shorelines of the Penghu Islands off the west coast of Taiwan. A marine biologist from Penghu Fishery Research Center collects coral spawn that have been released in the annual mass spawning event trigged by a full moon in spring.
This is a non-invasive method, meaning we take nothing away from existing coral ecosystems. Instead, we collect some of the billions of egg bundles released during the mass spawning event. There are so many egg bundles that the water’s surface appears pink – but only some of these are fertilised and become larvae.
Under the consent from local government and guidance from the Penghu Fishery Research Center, the eggs we collect are among those that wouldn’t otherwise survive. Collecting them therefore has no impact on the corals that originally released them, nor on the propagation of coral species.
For the next attempt at introducing corals to the offshore wind farm, sample sets will include corals collected and cultured since 2022, 2023, and 2024. This should give scientists a better idea as to the adaptiveness among different age groups to the same location.
We have everything ready to send the corals offshore, but we are dependent on the weather window. The corals should be installed at the turbines sometime between October 2024 and June 2025.
In June 2022, we completed our first seeding trial, using coral spawn collected from the spring mass spawning event, and a mesh cage that we attached to one turbine foundation piece. Early monitoring shows that the corals did not achieve the growth rates we expected.
This first attempt allows us to refine our approach for the next trial. We gathered the following learnings:
Ultimately, we hope to refine a method that can be deployed at a much greater scale than the trial at Greater Changhua offshore wind farms. If we are successful, this coral restoration method could be applied to the foundations of offshore wind turbines in any tropical waters around the world, boosting ocean biodiversity.