Nature-friendly decommissioning as an exception to the rule

Tuesday 25 August 2026

Hundreds of oil and gas platforms, along with a rapidly growing number of wind turbines and electricity infrastructure, are located in the North Sea. Although these structures can have negative effects on the marine ecosystem during construction and operation, a growing body of research shows that over time they can also develop significant ecological value. They provide habitat for species and can evolve into artificial reefs that are important to the underwater environment.

In addition, developers are implementing significant nature-enhancement measures, in some cases actively encouraged by the Ministry of Economic Affairs and Climate Policy through qualitative tender criteria. Offshore wind farms are increasingly equipped with artificial reefs and structures on which oysters and reef-building tube worms, among other species, can establish themselves. Combined with the fact that fishing is prohibited between the turbines, offshore wind farms could act as a catalyst for nature enhancement in the North Sea.

_{Van Oord’s Bravenes vessel places rocks around the foundation of a wind turbine at the Ecowende wind farm. The rocks are intended to protect against erosion, but they also attract a wide range of marine life.}

But these wind farms are not there forever. Over the next twenty to twenty-five years, a large number of offshore installations in the Dutch North Sea will reach the end of their operational life. For oil and gas installations, this is expected to involve around 150 platforms. The first offshore wind farms and associated grid infrastructure will also have to be decommissioned. The wind farms Egmond aan Zee and Prinses Amalia will be the first, followed by Luchterduinen. Egmond aan Zee has received a five-year life extension. It is not yet clear whether the same will happen for Prinses Amalia. Eneco has also applied for an extension of its permit, but is still awaiting a final decision. Together, this amounts to around 140 wind turbines and associated infrastructure over the next ten years.

For oil and gas platforms, the Dutch Mining Act requires them to be fully removed at the end of their operational life, with the exception of pipelines. For offshore wind farms, this requirement is set out in the Besluit activiteiten leefomgeving (Bal), the Dutch Activities in the Physical Environment Decree, as well as in the specific site decisions and permits. Developers must also provide a bank guarantee covering the decommissioning of the wind farm.

Current regulations require everything covered by the permit to be removed, including all nature-enhancement measures. This makes decommissioning not only a technical and logistical operation, but also a significant ecological intervention. Removing the structures also removes the habitats on and around which entire biological communities may have developed over the course of decades.

_{The rock placement around wind turbines provides an attractive habitat for shellfish and starfish.}

“So we first actively invest in nature enhancement, but then we are legally required to remove it again. There is currently no exception to this. That is rather remarkable,” says Pim Somers, who works on the issue as energy project lead at Stichting De Noordzee. Klaas Keuning, Operations Director of Ecowende, also questions the current approach. “We are putting all kinds of things on and around the wind farm with the aim of enhancing the underwater environment. I am referring to nature-friendly scour protection, a biodegradable reef structure made from fruit trees and an oyster larval network. It would be a shame if, provided these measures prove successful, we could not leave them in place.”

Where there is demonstrable ecological value, partial decommissioning could provide a solution. The wind turbines could be cut off at or below the seabed, thereby minimising damage to scour protection and any artificial reefs. A dedicated working group within OSPAR, the regional cooperation framework responsible for protecting the marine environment of the North-East Atlantic, is now exploring whether the legal framework can be adapted to allow exceptions to full decommissioning and thereby enable more nature-friendly options, such as partial decommissioning.

However, it must be prevented from becoming an excuse for leaving all kinds of materials on the North Sea seabed, Keuning warns. Decommissioning a wind farm is expensive, and companies could save a substantial amount of money if they were not required to carry it out in full. It is also important to establish who will be responsible for anything left on the seabed. These structures and responsibilities may extend over many decades, while wind farms themselves will not exist forever.

The intention is not, incidentally, to create an exception for all wind farms. “You should not want to leave things behind everywhere,” says Somers. “And from a circularity and safety perspective, full decommissioning can also be the right approach.” For example, steel foundation manufacturer SIF aims to recover the steel foundations it has produced and reuse the steel in new foundations.

Partial decommissioning should only be considered where there is genuine ecological added value in keeping the structures in place. That case therefore needs to be substantiated, and that is not straightforward, Somers explains. Although the first colonising organisms can establish themselves in a wind farm within a matter of months, it takes decades before the ecological value of nature development within offshore wind farms can be properly assessed.

_{Squid eggs attached to a PAM frame that Ecowende places on the seabed to measure underwater noise, including noise from harbour porpoises. The frame has been underwater for a year and is covered in marine life.}

The longest-running study of ecological communities on offshore wind turbines is being conducted in Belgium and has now been running for eleven years. That is still too short to draw definitive conclusions about their ecological value. “But research around oil and gas installations shows that real ecological value can develop,” says Somers. As an example, he cites cold-water corals (Lophelia pertusa), which are included on the OSPAR list of threatened species and can be found on oil and gas infrastructure in countries including Norway and Scotland. “But perhaps the best-known example is the Rigs-to-Reefs programme in the Gulf of Mexico, where around 600 platforms have been converted into rich artificial reefs,” says Somers.

With the first large-scale offshore decommissioning challenge approaching, it is therefore important to improve our ability to assess ecological value, Somers believes. “We need to draw as many lessons as possible from the first wind farms and invest in robust, standardised monitoring both before and after decommissioning activities.”

Stichting De Noordzee is not the only organisation calling for changes to the current regulatory framework. “It is difficult to explain that we first create nature and then have to remove it again because the rules require us to do so. If nature-friendly decommissioning is better for the North Sea ecosystem, the law should allow for it,” says Jan Vos, chairman of NedZero, the Dutch wind industry association. ElementNL, EBN, TenneT and Natuur & Milieu are also calling for this. Together, these organisations form the Nature-Friendly Decommissioning Coalition. Wind farm owners such as Ecowende are also part of the coalition.

The coalition recently developed scenario-based infographics on the ecological effects of offshore decommissioning. “They are intended as a discussion paper to advance the decommissioning debate and stimulate movement in national and international policy discussions, including within OSPAR,” says Somers.

Ultimately, it will come down to a case-by-case approach, Keuning believes. For each wind farm, it will have to be determined whether there is added value in leaving the structures in place. But if that added value exists, it would be a real shame to remove it again. “The North Sea was once a rich ecosystem. Much of that has disappeared as a result of human activity. Now, as wind farm owners, we can contribute to restoring it. It would be a shame if we did so only temporarily and then removed it again.”

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