04 12 2023

Nature-inclusive design: Aramis offshore pipeline and platforms

Ahead of the FEED phase (Front-End Engineering Design), Aramis and the North Sea Foundation are exploring ways to make the offshore pipeline and platforms as nature friendly as possible. “We design structures to be nature inclusive”, says Freija Rappoldt, Stakeholder Manager at Aramis. “One way of achieving this is by using recycled or natural materials, like oyster shells and calcareous rocks.” In collaboration with the North Sea Foundation, Wageningen University and others, Aramis has selected five nature-inclusive measures. Their feasibility will be explored by Aramis’ technical engineers in the upcoming FEED phase.

Marine ecologists from the North Sea Foundation shared their knowledge of nature-inclusive design in two workshops. Freija says, “They challenged our engineers to look beyond safety, technology and costs and inspired us to think about how Aramis could make a positive contribution to nature and biodiversity in the North Sea.”

Marine ecologist Eline van Onselen and her colleague Renate Olie took part in the workshops. Eline is involved with The Rich North Sea programme — an initiative of Natuur & Milieu (Nature & Environment) and the North Sea Foundation — and provides advice on the nature-inclusive construction of offshore wind farms. She explains, “Our knowledge in this area overlaps with subsea pipeline construction in several ways. We are pleased to contribute to this high-impact project.”

Five proposals for nature-inclusive design
The North Sea’s biodiversity has declined significantly in recent decades. “This is why nature-inclusive and nature-enhancing construction is so vital”, asserts Eline. “A nature-inclusive design is adapted to nature’s needs. This type of design can be used to create an artificial reef that acts as a water filter, food source and shelter area for fish. Natural reefs are becoming ever scarcer.”

Drawing on proposals and advice from the North Sea Foundation, the Aramis project team selected five potential measures for integrating natural features.

“A nature-inclusive design is adapted to nature’s needs”

Eline van Onselen

The first proposal concerns the location and protection of the pipeline. “Many pipelines are on the seabed, buried under the sand”, says Eline. “This protects them from erosion and fishing. But this cannot be done where pipelines or cables cross each other. Here, you need a different form of protection. One type of stone is commonly used around the pipeline or cable for this purpose. By varying the materials, rock types and textures, you can build a nature-inclusive form of protection, also referred to as an eco-crossing. You create a more diverse reef element by introducing greater variation.”

Cod hotel
Eline notes that the second option is a so-called cod hotel, which is also an artificial reef: “A kind of metal nest attached to the pipeline that provides a breeding and shelter area for fish like cod and catfish.”

Option three is the eco-anchor. This keeps floating components in place while enriching marine life. “You can simply drop a concrete block in the water or turn it into an artificial reef. Holes can be created for water purification, and it can be constructed by using various nutrient-rich materials. The more variety you introduce, the greater the biodiversity.”

While similar to a cod hotel, a biohut — option four — also promotes seaweed growth. A biohut consists of a metal frame attached to the pipeline. Seaweed, plants and other organisms latch on to it easily. Eline says, “You can put shell material, cork, wood and live oysters in the biohut. Although flat oysters are almost extinct in the North Sea, they are native to these waters. By releasing flat oysters into the sea, The Rich North Sea aims to give this species a boost.”

Nature-inclusive mattress
Option five is the nature-inclusive mattress, also called the marine matt. Like an eco-crossing, it protects the subsea pipeline from erosion while strengthening the natural ecosystem. Eline adds, “The mattress, which lies over the pipeline on the seabed, is also made of textured natural material.”

“I hope all the selected measures will find a place in the Aramis infrastructure”

Eline van Onselen

The more variation, the better
When asked which option she prefers, Eline replies without hesitation, “All five. The more variation, the better. I hope all the selected measures will find a place in the Aramis infrastructure. And not just regarding the pipeline: several of the proposals are also suitable for attaching flora and fauna to the platforms. This way, you help marine life both on the seabed and at higher depths.” Her advice is, above all, “Use everything at your disposal to ensure nature is included in the design.”

Decision on materials to be used
In the upcoming FEED phase, Aramis will examine the technical feasibility and safety of these nature-inclusive measures and decide which options to pursue. Obtaining the necessary permits will also be a decisive factor. Eline states, “The great thing about Aramis is heavy industry’s collaboration with NGOs and universities. That combination — inconceivable ten years ago — could lead to many beneficial outcomes.”

To give nature-inclusive design a further boost, at the end of this year Eline will, in association with The Rich North Sea, publish an online toolbox with practical information on its potential and applications. Eline concludes, “We will highlight trendsetting projects with nature-inclusive designs that have already been applied in practice. By combining different options, Aramis will be an excellent example of what can be achieved.’

Aramis Visual Natuurversterkend Bouwen EN