In western Limfjord, researchers and local partners are exploring how nature’s own processes can help deliver permanent CO₂ storage.  

The C-ASH project (Carbon-fixing by Volcanic Ash) is a collaboration between Aarhus University, Klimafonden Skive, Energibyen, and the municipalities of Skive, Morsø, and Thisted. Together, they are investigating how captured CO₂ can be safely and permanently stored underground by transforming it into solid limestone. 

The method is known as CO₂ mineralisation. Injected CO₂ reacts with volcanic ash layers in the subsurface of the Limfjord area, gradually forming stable carbonate minerals. This mimics a natural process that has occurred over millions of years, but here it is accelerated to deliver a safe, permanent storage solution with no risk of later re-emission. The approach is already used commercially in Iceland, and the conditions in western Limfjord appear particularly well-suited for scaling it up. Recent test drillings have reached 300 metres below ground and confirmed the presence of the volcanic ash layers needed for the process. 

Initial analyses point to an extraordinary potential, as the local underground has the potential to store the equivalent of 60 years of Denmark’s total CO₂ emissions. If proven at scale, this would be a step towards reaching Denmark’s climate goals. For the local business community, it opens the door to new opportunities within the emerging CO₂ economy, complementing existing strengths in industrial symbiosis and sustainable production. 

By combining advanced research with strong local partnerships, C-ASH demonstrates how innovation can transform climate challenges into drivers of regional growth.