Can offshore wind turbines save coral reefs?

Coral reefs are under threat from rising sea temperatures caused by the climate crisis. Credit: Ørsted

Wind turbines, already a cornerstone of green energy, may now be used to help save the world's coral reefs from the devastating effects of climate change with a new project that seeks to grow corals on and around them.

The ReCoral by ØrstedTM project hopes the foundations of wind turbines will provide a "safe haven" for coral to grow and flourish, and is testing the concept on four wind turbines in Taiwan this summer.

"The foundations of offshore wind turbines provide a unique environment where corals can grow close enough to the surface to receive enough sunlight, but without being exposed to high temperatures. This limits the risk of coral bleaching," Ørsted said.

Could this project help restore and regenerate the world's under-threat coral reefs - and how will it work?

What does ReCoral project involve?

The idea behind the project is to use surplus indigenous coral spawn, collected after it has washed ashore, and use it to grow coral colonies on the foundations of offshore wind turbines.

The idea is being tested this summer, when the ReCoral team and their colleagues from the Penghu Marine Biology Research Centre will take tens of thousands of these coral larvae to the foundations of four offshore wind turbines in Taiwan. It is hoped these larvae will succeed in settling on the foundations and begin to reproduce.

Mature corals will release their own spawn, which could be carried by ocean currents to settle naturally elsewhere, the researchers say.  

Artist’s impression of future coral growth potential. Credit: Ørsted

How will it work?

Offshore wind farms offer relatively stable water temperatures that will limit the risk of coral bleaching and allow healthy corals to grow on wind turbine foundations.

Corals will be grown close to the water's surface to ensure sufficient sunlight.

In 2021, the ReCoral team successfully grew juvenile corals on underwater steel and concrete substrates at a quayside test facility for the first time. 

Rather than removing anything from existing coral ecosystems, ReCoral’s non-invasive approach relies on the collection of surplus coral egg bundles that wash up on shorelines and would not otherwise survive.

Mads Nipper, Group President and CEO of Ørsted, said: “To halt climate change and create a sustainable future for the planet, its ecosystems, and its people, we must speed up the transition from fossil fuels to renewables. Governments are preparing a significant expansion of offshore wind energy, and I’m confident that if done right, the offshore wind build-out can support and enhance ocean biodiversity.”

Why are coral reefs important?

According to the UN Environment Programme, coral reefs provide habitat for an estimated 32% of all marine species and benefit one billion people worldwide, directly or indirectly.

Coral reefs are among the most diverse and valuable ecosystems on the planet but are under threat from warming seas caused by the climate crisis.

Increasing warm oceans are causing coral bleaching, when the coral is stripped of its vibrant colours and becomes white, a process that threatens the survival of coral reef ecosystems. The damage is so widespread, the International Union for Conservation of Nature has designated coral an endangered species.