This is how offshore wind farms can become havens for marine life

Offshore wind farms have been called many things - a marine habitat is not necessarily one of them. But that’s exactly what’s happening off the coast of Virginia in the United States.

Drawing on the success of offshore wind in Europe, the rollout of wind farms is now also accelerating along US coastlines, supported by the government, which has set a goal of 100% carbon-free electricity by 2035.

As part of a pilot project, the US’s first two offshore wind turbines were installed off the coast of Virginia Beach in 2020, some 27 miles from the mainland. Since starting to operate in October that year, the turbines’ steel foundations have become a habitat for a range of ocean species.

According to the Virginian-Pilot newspaper, algae and mussels have attached themselves to the structures while schools of fish - including mahi, sea bass and bait fish - now circle the foundations. Sea turtles and sunfish have also been spotted near the turbines. Some marine creatures have even made their home inside the structures, benefitting from venting holes, the newspaper reports.

This emerging ocean ecosystem was discovered when wind farm operator, Dominion Energy, reviewed monitoring videos of the site.

The two turbines started operating last October as a pilot for the largest offshore wind development in the Americas to date, set to power more than 650,000 homes by 2026. As part of monitoring and evaluating the pilot site and the turbines’ impact on their marine environment, Dominion took underwater videos of the steel foundations in six-monthly intervals.

A comparison revealed significant changes to the marine life near the site over that time period. In a development also seen at other offshore wind sites and oil rigs, the two structures have become a new habitat for fish and other species that wouldn’t typically settle this far out at sea.

The turbine foundations have become artificial reefs that give species like mussels, which require hard surfaces to attach to, the right environment to thrive. In turn, their presence attracts fish in search of a food source.

Despite this positive impact on the oceans’ biodiversity, artificial reefs also have significant downsides. While creating new habitats for some species, they can have a negative effect on others, according to a recent paper in Oceanography. This potentially includes commercial fish stocks, whose habitats wind farms may invade. Both desired and undesired effects need to be thought through early on, the paper recommends.

Dominion Energy is working with the Virginia Institute of Marine Science to design scientific studies at the pilot site, including evaluating the turbines’ effects on local fisheries, for example. The company already uses mechanisms such as a “large bubble curtain” to avoid construction noise and vibrations travelling and causing harm to ocean dwellers.

But it’s not only marine animals that are affected by wind farms at sea.

With the European Union aiming to scale offshore wind to 25 times its current capacity by 2050, a new report from BirdLife warns that such an expansion poses a threat to seabird populations.

In particular, it cautions, measures must be put in place to avoid birds colliding with offshore wind turbines. This is especially true for breeds like the northern gannet and the black-legged kittiwake, which have been identified as being at high risk of collision where wind farms touch their breeding, migration or wintering grounds.

The study highlights the need for strong spatial planning to reduce these effects on seabirds as offshore wind continues to expand. The Norwegian Institute for Nature Research has suggested that simply painting one of the turbine blades black could make a significant difference to bird survival, too.

Between now and 2050, offshore wind is set to be the central pillar for global decarbonization, at the core of transforming large swathes of our energy system. To achieve the net-zero emissions target by 2050 and rein in climate change in line with the Paris Agreement, offshore capacity will need to expand from 35 gigawatts (GW) in 2020 to 2,000 GW in the next three decades, says the Global Wind Energy Council.

To further boost technologies available to keep the world on the net-zero pathway, the World Economic Forum’s innovation crowdsourcing hub, UpLink, has launched an initiative to source new solutions for “Accelerating Clean Energy Transitions”. This includes a solution for using wind more effectively.

With biodiversity and climate change inextricably linked, the challenge will be to balance the needs of both when it comes to building more offshore wind capacity.