In the European North Sea, wind farms offer sanctuary to marine life
Nature conservation and wind power generation may overlap in the oceans – for now.
Rarely do today’s increasingly gargantuan wind farms earn points for their respect for nature. Offshore wind turbines are killing birds, confusing dolphins and crushing seabed aquaculture, environmentalists charge. But, according to a new report in The Anthropocene magazine, marine researchers in the North Sea – from several countries and independently of each other – have come to the same unorthodox conclusions: offshore wind farms protect and even nurture a range of marine life, including endangered species such as the North Sea cod and gray seals.
The North Sea is the site of these counterintuitive discoveries because its shallow waters and gusty coastlines have been home to modern turbines for twenty years – longer than anywhere else in the world. During this period, wind farms in northern Europe in the waters of half a dozen countries were closed off to the fishing industry. This has allowed their underwater surroundings to develop without being violated by the boats and trawls that rake the seas and clean their floors.
And the foundations of the turbines on the seabed can also function as artificial reefs on which flora and crustaceans thrive, which are then eaten by fish, porpoises and seals. Researchers have found that marine renewable energy parks can serve as vast sanctuaries for marine life – a Kinderstubeor nursery, for underwater species, say the Germans – some of them as wide as 80 km2 in size.
The findings are highly relevant, as offshore wind energy needs to be significantly developed in the near future – in Europe and globally – in order to meet the goals of the 2015 Paris Agreement.
Until now, this prospect has largely been one of the main concerns of conservationists. Planting the giant steel piles into the seabed destroys part of the seabed and disperses sediment, which disrupts marine ecosystems for miles. During survey and installation procedures, vessels come into collision with marine mammals, sea turtles and fish. And once in place, noise and electromagnetic fields can distract large fish for the entire productive life of the turbine. Once decommissioned, masts sunk 30 meters into the seabed must be removed or replaced (a dirty and expensive procedure that currently occurs on North Sea oil and gas rigs.)
But a growing body of multinational research, some of which is still ongoing, reveals that protected marine space could be crucial for rejuvenating fish stocks, shellfish populations and aquatic marine mammals. Wind farms could actually benefit the natural world – far beyond generating carbon-free energy.
Scientists from the University of St. Andrews in Scotland tracked gray and harbor seals tagged with GPS tags off the Dutch and British coasts. They saw that some of the mammals in German and British wind farms swam from one wind turbine to another, sometimes stopping to feed around the masts. The work coincided with findings that harbor porpoises, a highly endangered species, tended to gravitate towards wind farms in Dutch waters, either for protection or to find prey, such as gobies, herring and sand lance.
In Germany, researchers have located cod and planted young populations of lobsters in wind farms. Vanessa Stelzenmüller, a marine biologist from the Johann Heinrich von Thünen Institute based in Germany, tracked schools of North Sea cod off the small archipelago of Heligoland, about 80 km north of the port city of Bremerhaven. North Sea cod, a favorite of seafood lovers, has been significantly overfished, leading to a steep decline in the population. Warming sea waters, due to climate change, are another contributing factor, says Stelzenmüller.
Stelzenmüller observed the species at a German wind farm with 80 wind turbines that generates enough electricity for around 320,000 homes. Not only did the cod live in the park, but “we found that their condition was better than that of the cod outside the park,” says Stelzenmüller. Recently, she and her colleagues found that cod were also breeding there. “It’s remarkable,” she said The Anthropocene, “that even despite the warmer waters of the southern North Sea, the wind farm habitat suits them better than in the colder northern parts of the sea.” They have better shelter, protection and forage options.
European lobster is yet another beneficiary. When marine scientists released 2,500 baby lobsters into and around the rock foundations of a North Sea park in the German Bight, they didn’t know what to expect. Three years later, the lobster population had increased, albeit slightly. They were healthy and larger in size than farmed lobsters.
The emergence of wind farms as safe areas for marine life coincides with studies showing that wind farms, when not located in the path of migratory routes, do not kill large birds in large numbers (the research on small birds is inconclusive). Harbor seals are also not annoyed by the sound of turbines once the masts are sunk into the seabed.
Yet sea protection advocates have said The Anthropocene that several times as many turbines in the North Sea is quite another story. The cumulative impact of so many turbines carries another quality of systemic risks, they say. Wind farms can benefit nature, they admit, but their expansion must be executed with levity and a lot of planning.