What Do Offshore Wind Farms Mean For The Oceans?

Sami Grover
Published: March 16, 2017

A service vessel makes its way past wind turbines run by Germany's biggest power supplier Eon at the offshore wind farm 'Amrumbank West' near the North Sea Island of Helgoland.

In the last decade or two, offshore wind farms have gone from a rare sight to a major player in the world’s energy mix. In the U.K., in particular, the coastline is now dotted with vast arrays of turbines which make up a whopping 5 gigawatts (GW) of capacity in total. There’s another 6GW or so of capacity in the rest of Europe. And recent developments suggest the industry is hitting record low prices well ahead of its stated goals, suggesting that further rapid expansion may be on the cards.


Meanwhile, the U.S. has just five operational offshore turbines, totaling 30 megawatts (MW) of capacity.


While clean energy advocates and activists have welcomed the spread of large-scale offshore wind — and they continue to hold out hope for a similar expansion in the U.S. eventually — there are still question marks about what, exactly, the impacts of offshore wind farms are on the oceans in which they are located.


One article in Gizmodo, for example, highlighted new satellite imagery from NASA showing a surprising and unexpected consequence of offshore wind — vast plumes of sediment stretching for many miles from the base of offshore turbines. While the article suggested that the impact of such plumes on fish nurseries and marine life is currently unclear, the very fact that the effect is visible from space suggests that further study is warranted.


Similarly, the impact of large-scale wind farms on wind patterns and localized climate has been a topic of much discussion. While anti-wind energy lobby groups have suggested that widespread deployment could disrupt regional climates and cause unintended consequences, research has largely dispelled these myths and found only minimal, localized changes to temperature or airflow.


But what about more localized impact on marine life? A 2014 paper by University of Maryland Center for Environmental Science researcher Helen Bailey called for ongoing monitoring of potential offshore wind development sites, with a view to both more careful siting of projects, and also identifying ways to minimize harm during construction and operation. Here’s how Bailey described the challenge in a press release:


“As the number and size of offshore wind developments increases, there is a growing need to consider the consequences and cumulative impacts of these activities on marine species. It is essential to identify where whales, dolphins and other species occur to help avoid adverse impacts and to continue to monitor their response to the construction and operation of wind turbines.”


The sun sets over the Burbo Bank wind farm in the Irish Sea viewed from New Brighton, north west England.
(PAUL ELLIS/AFP/Getty Images)

Since the publication of that paper, industry groups and environmentalists alike have been working hard to solve this puzzle. A recent study by the World Wildlife Fund suggests there are plenty of reasons to be hopeful. By deploying a wide range of methods including altering piling schedules, air-filled tubes, hydro-sound dampeners, and even utilizing bubbles as a barrier against underwater sound waves, the research suggested that a drop of even 8 decibels in construction noise could significantly reduce the chance of a decline in North Sea porpoise populations.


Of course, it’s foolish to talk about the potential negative of impact offshore wind turbines without acknowledging the huge upsides. Given the devastating losses to marine life that we are already seeing due to climate change and ocean acidification, any localized damage caused by wind turbine production should be weighed against the reductions in carbon emissions and other pollutants that are achieved by switching to renewables.


Similarly, it’s worth noting that some research has suggested that, much like offshore oil rigs, wind turbines also serve as artificial reefs. Whether or not this creates a net positive for marine life or — as one long-term study into Sweden’s largest wind farm has suggested — merely means that turbines have a largely neutral localized impact, is another factor worthy of further study.


Given that offshore wind has only really taken off since the turn of the millennium, it’s perhaps no surprise that there are as many questions as there are answers about the eventual impact on marine life. One thing is certain, however, the longer we allow carbon emissions to grow unchecked, the more trouble we will find our oceans in. So far, offshore wind has proven to be a powerful tool in curbing such emissions, not to mention the mercury that starts out in coal-fired power plants and ends up in our tuna. Making sure that this promising technology meets its full potential will require keeping an eye on its impacts, and continuing to ensure that wind farms are developed as cleanly and responsibly as possible.

Sami Grover is a writer, and creative director at The Change Creation, a brand creation agency that works with entities who make the world better, fairer or truer. Clients include Larry’s Beans, Burt's Bees, Canaan Fair Trade and Jada Pinkett Smith/Overbrook Entertainment.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.