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ISSN 2753-7757 (Online)
Kelp tied to a rope Photo: SINTEF Ocean
It is hoped that kelp cultivation will be able to capture millions of tonnes of CO2 and help tackle climate change

Photo: SINTEF Ocean

SINTEF, DNV, Equinor and Lundin have signed an agreement to make what is claimed will be the world’s first pilot project for active, nature-based carbon capture at sea. The goal is to develop technology and methods that can capture millions of tonnes of CO2 with the help of kelp cultivation.

The Norwegian project plans to cultivate large amounts of sugar kelp on long ropes connected to buoys set out to sea, placed in areas with a natural capacity for kelp cultivation. With the help of photosynthesis, the kelp will utilise the sunlight to grow and bind carbon from the atmosphere, replicating the process that trees and plants perform on land. After approximately six months in the ocean, the kelp will have bound the maximum amount of CO2 and is thus ready for harvesting and further processing for carbon storage.


‘In order to solve the major climate challenges our planet is facing, we need research – not just in order to reduce CO2 emissions, but also to remove emissions that already exist in the ocean and the atmosphere,’ explains SINTEF Ocean CEO Vegar Johansen. ‘This is a concept where the possibilities for upscaling are very promising,’ he adds, as the technology would be exported and used successfully in many places throughout the world.


The pilot project will run until 2024, and from 2025, will transition into a commercial upscaling phase with one or more large facilities off the coast of Trøndelag. The goal is then to demonstrate the potential of the upscalable technology for carbon capture on an industrial scale.


Two alternative use cases for kelp will be tested.

  • Bio-coal: Harvested kelp goes through a pyrolysis process where it is blended with composted kelp and soil, before being used for soil improvement. The process gives environmentally friendly and nutrient-rich fertiliser, at the same time as carbon is stored safely and securely in the ground.
  • Storage in the ocean floor: Harvested kelp is sunk to the ocean floor, to depths greater than 1,000 metres. At such depths, the material mixes with surface water at a very slow rate, and thus remains in the sediments, eliminating the emission of greenhouse gases into the atmosphere.


The pilot project will also include a study of the environmental effects of large-scale kelp cultivation and carbon storage.