In the course of the three years, both biochar from cultivated seaweed and organic carbon losses from seaweed farming have been investigated, whereof biochar for use as a soil amendment represents the most mature carbon pathway.
In addition, the EU recently adopted the classification of biochar as a permanent carbon storage, which further supports investments in new, regenerative biomass production to ensure a sustainable supply for this purpose.
Not negative emission with today’s value chain
When cultivating kelp in open, exposed sea, the project emissions are, however, currently estimated to be higher than the carbon removal potential of the biochar, due to the steel and fossil fuel needed when farming under these conditions.
Further research and technology development is needed to mature the seaweed CDR value chain, including monitoring, registration and verification (MRV) for passive removals.
Continued efforts to scale up the seaweed cultivation and processing value chain can enable long-term carbon storage and verification of such, hence the possibility for certified CO2 removals through both seaweed cultivation (passive, marine CDR) and biomass conversion (biochar) in the future.