Company Plans To Use Offshore Foundations as Safe Havens for Corals

As climate change threatens reefs with bleaching, Danish energy company Ørsted is looking at growing noninvasive coral on offshore wind turbine foundations.

An artist’s impression shows the potential for future coral growth on offshore foundations.
Source: Ørsted

Danish energy company Ørsted is planning to try to grow corals on offshore wind turbine foundations. Together with Taiwanese partners, the company will test the concept in the tropical waters of Taiwan in summer 2022. The goals are to determine whether corals can be grown on offshore wind turbine foundations and to evaluate the potential positive biodiversity effect of scaling up the initiative.

According to the UN Environment Programme, coral reefs provide habitat for an estimated 32% of all marine species and benefit 1 billion people worldwide, directly or indirectly. But climate change is increasing sea surface temperatures, which can create a bleaching effect that threatens the survival of tropical coral reef ecosystems, adding to the global biodiversity crisis.

Ørsted has set a goal to deliver a positive effect on biodiversity with all the new energy projects it commissions from 2030. Its ReCoral project aims to implement a noninvasive approach for collecting surplus indigenous coral spawn as it washes ashore and to grow healthy coral colonies on the foundations of nearby offshore wind turbines.

The Idea
Although increased surface temperatures in shallow waters can lead to coral bleaching, at offshore wind farm locations further offshore, temperatures are more stable because vertical mixing in the water column prevents extreme temperature increases.

The idea behind ReCoral is that the relatively stable water temperatures at offshore wind farm locations 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 they can receive sufficient sunlight.

In 2020, biologists and marine specialists in Ørsted teamed with private and academic coral experts to test the concept. In 2021, the ReCoral team successfully grew juvenile corals on underwater steel and concrete substrates at a quayside test facility for the first time.

In June 2022, the offshore proof-of-concept trial will begin at the Greater Changhua offshore wind farms in Taiwan to test the concept in open waters on four wind turbine foundations.

“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,” said Mads Nipper, group president and CEO of Ørsted. “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. … If we succeed with ReCoral and the concept proves to be scalable, this Ørsted innovation could create a significant positive impact on ocean biodiversity.”

Working With Coral Experts
Ørsted is collaborating with the Penghu Marine Biology Research Center in Taiwan, and together they have developed a noninvasive methodology for coral seeding, in-vitro fertilization, larvae transport, and larvae attachment to wind turbine foundations. Rather than removing anything from existing coral ecosystems, ReCoral’s noninvasive approach relies on the collection of surplus coral egg bundles that wash up on shorelines and would not otherwise survive.

“Environmental protection and marine biodiversity will continue to be one of the key topics of the world in the coming decade,” said Hern-Yi Hsieh, the director of the Penghu Marine Biology Research Center. “It’s great to see that, apart from its effort to supply clean energy, Ørsted is also launching its coral project here in Taiwan to promote environmental friendliness.”

If the proof-of-concept trial is successful, Ørsted has said it will explore opportunities for scaling up the initiative, with the ultimate goal of using additional coral larvae generated at offshore wind farm locations to restore and enhance threatened near-shore reef systems.

Ørsted has said that its ReCoral concept could be applied to offshore foundations of any kind in tropical waters.

ReCoral: Giving coral a home among our wind turbines