Ørsted and the World Wide Fund for Nature (WWF Denmark) are testing how 3D printed reefs can benefit biodiversity in the Kattegat, a strait between Denmark and Sweden, which is experiencing a historically low cod stock. This is the first time 3D printed reefs are being used in Danish waters, and they will complement existing boulder reefs that Ørsted established when constructing the Anholt Offshore Wind Farm in 2012-13.
Ørsted and WWF have deployed 12 3D printed reef structures on the seabed between the wind turbines at Anholt Offshore Wind Farm in the Kattegat, which is part of the Greater North Sea ecosystem. Among other things, overfishing, increasing oxygen depletion, and habitat loss have resulted in a decline of the cod stock in the Kattegat over the past 20 years. According to Ørsted – it is now alarmingly low. This creates a negative domino effect in the Kattegat ecosystem, impacting biodiversity and the marine ecosystem’s resilience against climate-driven changes.
The two partners hope that it will have positive effects on the Kattegat cod stock and, in turn, contribute to a healthier, more resilient marine ecosystem with improved biodiversity.
”The ocean holds vast potential to help meet our climate goals. Improving ocean health and restoring marine biodiversity is fundamental to addressing biodiversity loss and the climate crisis. As governments around the world are ramping up ambitious plans to grow renewable energy capacity, offshore wind will take up more space. At Ørsted, we believe action on climate and nature can and must go hand-in-hand, and this exciting project together with WWF Denmark is one of many we’re testing out globally to seek the best solutions to make our ambition of a net-positive biodiversity impact a reality,” said Filip Engel, Vice President of Sustainability at Ørsted.
”Marine biodiversity in Denmark is under heavy pressure, and today there are 90 % fewer cod in the Kattegat than in 1990. Action is needed – and urgently. We must give nature and wildlife a hand, while trying to solve our climate crisis by expanding our renewable energy production at the same time. To solve the nature crisis, we must leave nature in better shape than before. That’s why we’re very excited that we, together with Ørsted, can test the new, unique 3D-printed reef structures here in Denmark for the first time,” said Bo Øksnebjerg, Secretary General, WWF Denmark.
In recent decades, attention has been drawn to the fact that the extensive overconsumption of marine resources has had enormous consequences. Globally, these consequences include dwindling fish stocks, oxygen depletion near the seabed, and a loss of habitats for marine life – such as a massive reduction of eelgrass meadows.
Cod is an important top predator, meaning it preys on other marine species and thereby contributes greatly to maintaining the balance in the marine ecosystem. When cod gets greatly reduced in numbers, the abundance of their prey – such as the green crab – will grow. As a result, seagrasses decline because the crabs eat both the seeds of the eelgrass and many of the snails that keep the eelgrass free from being overgrown with algae.
This is a problem, as eelgrass is itself of great importance for both biodiversity and the climate. It provides important habitats for marine life, such as juvenile fish, produces oxygen, and stabilizes the seabed. Crucially, eelgrass also very effectively stores carbon in its root network, preventing it from ending up in the atmosphere and contributing to the global temperature rise.
Last year, WWF Denmark and Ørsted installed biohuts at the piers in the port of Grenaa, in collaboration with the Port of Grenaa and the Kattegat Centre. Together, the two projects offer new habitats for cod at key stages in their life cycle. Biohuts can be described as fish kindergartens as they provide vital protection to small fish. Here, juvenile cod, for example, can seek shelter and food until they are large enough to swim out into deeper water.
The 3D printed reefs are designed and developed based on a collaboration between WWF Netherlands and Reef Design Lab, and are produced by the Italian company, D-Shape.
The 3D printed reefs look like a wedding cake consisting of several levels that are connected by hollows where fish can swim in and out of hiding places. At the same time, the structures themselves will provide surfaces and crevices where other organisms can attach. The reefs are about one cubic meter in size and vary in width and weight to best imitate natural habitats. Each reef weighs between 200 and 550kg. The reefs are made from 70% sand and 30 % pozzolanic cement – made from volcanic ash and portland cement. These natural materials are not harmful to the surrounding environment, even if parts of the reefs erode over time. The 3D printed reefs are biocompatible – due to the absence of synthetic or toxic substances of industrial origin – and have a moderately basic pH of around 8.5-9.
Ørsted has seen how the boulder reefs that the company established when constructing the Anholt Offshore Wind Farm have become attractive oases for other marine species on an otherwise barren seabed. The expectation is that the new 3D printed reefs will complement the stone reefs and will quickly become inhabited with life. WWF already has experience with 3D printed reefs from a project in the Dutch part of the North Sea.
”We’re very proud to see Anholt Offshore Wind Farm pioneer 3D printed reefs in Danish waters. Biodiversity is a focal point for PensionDanmark, and if this innovative initiative can improve biodiversity in the marine ecosystem, while the wind farm is producing sustainable power, we have a win-win situation for all concerned,” said Torben Möger Pedersen, CEO at PensionDanmark, which has a 30% share in the wind farm.
”Protecting our planet and working towards a sustainable future is important to us. Biodiversity is decreasing worldwide at an alarming rate. We’re proud to support the test of artificial reefs at the Anholt Offshore Wind Farm and its attempt to improve conditions for cod and the wider biodiversity in the area and the Kattegat. We’re looking forward to following the development of marine life conditions in the coming years,” said Jon Johnson, CEO of PKA A/S, which has a 20% share in the wind farm.
Ørsted has set the goal to create a net-positive biodiversity impact for all new renewable energy projects commissioned from 2030. Ørsted is working together with several ecology experts on different projects to restore and enhance biodiversity – such as Dutch ARK Nature in a pioneer project in the North Sea – and with two local wildlife trusts in a flagship project on the Humber estuary on the east coast of Northern England. The company also recently announced ReCoral by ØrstedTM, a world-first attempt at supporting coral reefs by growing corals on offshore wind turbine foundations in Taiwan.
This project is part of a strategic partnership between Ørsted and WWF Denmark initiated in 2018. Its purpose is to contribute to saving the world’s climate-threatened wildlife and nature, while also engaging the Danish population in solutions to global warming and creating a society that runs solely on green energy.