An assessment of global resources of rocks as suitable raw materials for carbon capture and storage by mineralisation

Carbon capture and storage by mineralisation (CCSM) is a method proposed for capturing CO₂ by reacting it with magnesium in ultramafic rocks to form carbonate minerals and silica. Large quantities of magnesium silicate rocks are required for this process and to demonstrate the feasibility, and adequately plan for the development and supply of mineral resources, their locations and quantities must be known. This study attempts to globally define the spatial extent and quantity of resources that could be used for the CCSM processes and to assess, if based on resources, this could be a viable, widely applicable CO₂ sequestration process. It has been estimated that around 90 teratonnes of material is available. This is sufficient to capture global CO₂ emissions for over 700 years at current levels of output and highlights the enormous resource. Even if only a small part is utilised, it could make a significant impact on CO₂ reduction. The majority of the resource is contained within ophiolitic rocks. The study further attempts to split CCSM resources into altered (serpentine-rich rocks) and unaltered (olivine-rich rocks) due to the different processing requirements for these rock types. Carbon capture and storage by mineralisation is likely to be of most use in areas with no access to underground geological CO₂ storage or for small operations where underground storage is not practical. This study demonstrates that substantial resources are available and their supply is unlikely to be a constraint.