A three-year project off the Norwegian coast aims to discover whether seaweed can be an alternative to industrial-scale CO2 capture and storage. The concept behind the innovative technology is to use seaweed farms to capture carbon instead of taking valuable land space. Growing the seaweed relies on sea nutrients and photosynthesis, which cost nothing.
The technology and infrastructure to leverage the project into a CCS that can scale globally, however, will be expensive. Seaweed – a joint industry project (JIT) – will test whether that is possible and try to compete with already established CCS projects on an industrial scale.
The JIT started its first project in April 2022 with financial support from oil and gas companies Equinor (based in Norway) and Lundin Energy (based in Sweden). Lundin Energy recently changed its name to Orrön Energy after it exited the oil business to focus on renewables. Among the other financial supporters are Norway’s risk management firm DNV and SINTEF, an applied research group that leads the $3-million pilot, which will continue until the end of 2024.
In case of success, DNV said commercial-scale seaweed production could start offshore in central Norway from 2025 from one or several farms. The company also stated the goal would be to capture millions of metric tons per annum (mtpa) of carbon.
Trondheim-based SINTEF estimates that removing 2,500 metric tons of CO2 requires about 20,000 metric tons of seaweed to be grown across an area of 1 km2. That means capturing 5 mtpa of CO2—or about 12% of Norway’s total annual emissions—requires on the order of 2000 km2 of the ocean surface to be covered with seaweed farming installations.
According to SINTEF, 2,500 metric tons of carbon dioxide require about 20,000 metric tons of seaweed grown on 1 km2. That means that to capture 12% of Norway’s total yearly emissions, 2000 km2 of seaweed-covered ocean surface would be needed.
Seaweed is mostly grown for human consumption, animal food, and cosmetics and the world cultivates about 27 million metric tons of it per year. The sea culture is easy to grow, does not require pesticides, and grows fast. Currently predominantly harvested by hand, the seaweed technology will require automation to reach scalability. To achieve this, SINTEF is considering repurposing automated fishery systems.