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Isometric recently released two modules on the storage of carbon dioxide via mineralization for public consultation—Carbon Dioxide Storage via Ex Situ Mineralization in Closed Engineered Systems and Carbonated Materials Storage and Monitoring.
These modules detail durability and monitoring requirements and procedures for carbon dioxide storage via mineralization.
Ex-situ mineralization (eEXM) involves taking a stream of concentrated carbon dioxide (typically from a Direct Air Capture or BCCS project) and injecting it into a reactor that is filled with finely crushed rock, such as ultramafic mine tailings. There, carbon dioxide reacts with rock to form carbonate minerals. After this mineralization reaction takes place, the carbonated materials are removed from the reactor. These carbonated minerals store carbon for thousands of years under conditions on the Earth’s surface.
However, under certain conditions, carbon dioxide from carbonate minerals can be released. These conditions are uncommon, but possible, for storage above and below ground. Therefore, carbonated materials must be stored in an environment where possible reversal risks (such as acidic or high-temperature conditions) are avoided. This ensures the carbon stored through the process remains stable and carbon removal is maintained.
The Carbonated Materials Storage and Monitoring Module provides guidance on storage site selection, characterization and on-going monitoring requirements. This includes requirements for both open and closed system storage environments.
eEXM is part of a closed system process, which means carbon removal can be quantified and measured directly on-site, providing high confidence in credit generation for both buyers and suppliers. The eEXM module requires suppliers to comply with two key points to ensure the process is rigorous:
- System requirements: suppliers must provide comprehensive documentation on reactor design and maintenance to ensure optimal functionality
- Direct measurement of inputs and outputs from the reactor system
These modules were created in collaboration between Isometric’s in-house Science Team and reviewers from Isometric’s independent Science Network of over 200 scientists and climate experts. Comments during the consultation period are welcome from interested buyers, suppliers and scientists and will be considered before the modules are finalized.
