Under offshore wind turbines, researchers grow seafood and seaweed

KRIEGERS FLAK OFFSHORE WIND FARM, Denmark (AP) — In a small boat bobbing in the waves among towering waters wind turbinesResearchers in Europe’s Baltic Sea reach the frigid waters and remove long lines stretched between poles where mussels and seaweed grow.

It is part of efforts to explore multiple uses for remote offshore wind farms, such as producing fresh seafood.

Led by Swedish state energy company Vattenfall and Denmark’s Aarhus University, the four-year project began in 2023 on the Danish east coast at Scandinavia’s largest wind farm, Krieger flakes. With the first harvest just 18 months later, it is already showing signs of early success.

“There is increasing competition for space on land and at sea,” said Aarhus University senior scientist Annette Bruhn, who is leading the project. “We can, in one area, produce fossil-free energy and food for a growing population.”

With a capacity of more than 600 megawatts, Kriegers Flak can supply up to 600,000 homes. Its 72 turbines provide clean energy to neighboring Denmark and Germany to the south.

But researchers saw other potential in the park’s 132-square-kilometer (51-square-mile) area.

The water between its rotating blades has been transformed into an experimental underwater seafood farm.

Four-hundred-meter (328-foot) rows spread between the turbines grow seaweed and mussels. The seaweed was recently harvested for the first time.

“Seaweed and mussels are low-trophic aquaculture crops, which means they can be produced without the use of fertilizers. They absorb nutrients from the sea and produce healthy food,” Bruhn said.

Recent modeling from Aarhus University suggests that tonnes of fresh seafood could be produced annually using just a tenth of Denmark’s wind farm area. Researchers say the benefits could go far beyond food production – mussel and seaweed farming can help improve water quality and capture carbon.

“These are unfed crops that live off what they take from the sea, they capture emissions instead of emitting,” Bruhn said.

Researchers say now is the time to develop guidelines to encourage companies to plan for multiple uses of the ocean, as European nations massively increase oil production. clean energy from wind turbines in the North Sea.

In 1991, Denmark became the first country in the world to install a commercial offshore wind farm. More than 30 years later, almost half of Danish electricity production comes from wind turbines.

Driven to meet climate goals and reduce energy dependence on Russia, nine European countries, including Denmark, announced plans last year quadruple current production to 120 gigawatts by the end of the decade and move to 300 gigawatts by 2050.

Vattenfall bioscience expert Tim Wilms said there is “huge potential”.

“We have a lot of untapped area within our turbines that is not being used,” he said.

“In some areas it makes a lot of sense to combine with sustainable food,” while in other areas “we can look at offshore solar.”

A growing body of research shows that offshore wind farms can have both positive and negative impacts on local ecosystems.

Offshore projects have been criticized for the damage caused to the seabed during construction, noise pollution and now debunked claims that caused whale deaths.

However, the large rocks placed at the base of the turbines to prevent erosion can also function as artificial reefs, attracting more marine life and protecting them from large-scale fishing operations.

Wilms said underwater surveys of older wind farms have revealed “completely transformed” structures covered in different species.

Liselotte Hohwy Stokholm, CEO of the Danish think tank Ocean Institute, said more “knowledge about mixed-use developments” is needed to understand how to combine human activities so that large areas of the ocean can become “strictly protected areas”.

Currently, efforts are on a limited scale, but researchers hope to soon bring their knowledge to the extreme conditions of the North Sea, eventually increasing commercial food production.

“It’s really important that we do this now because there are a lot of questions we still need to answer before we can do this right,” Bruhn said.

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