Isometric recently released the draft Enhanced Weathering in Closed Engineered Systems Module for public consultation. This module details requirements and procedures for the durable storage of carbon dioxide via Enhanced Weathering conducted in closed, engineered systems.
Enhanced Weathering (EW) is a carbon dioxide removal (CDR) technology that accelerates the Earth’s natural weathering process. In nature, carbon dioxide dissolved in rainwater reacts with minerals in rocks, forming stable bicarbonate ions. These ions are carried by rivers to the ocean, where they are durably stored for tens of thousands of years. Typically, in EW, this process is accelerated by crushing rocks into a fine powder and applying it to soil, which dramatically increases the surface area of the rocks, enabling them to react more readily with carbon dioxide.
EW can also take place in closed systems. In this approach, carbon dioxide removed from the atmosphere through other CDR technologies—such as Direct Air Capture (DAC)—is dissolved in water. This solution mimics the role of rainwater in natural weathering and is reacted with minerals in an engineered, closed chamber, known as a reactor. As in natural weathering, this produces bicarbonate ions, which can be safely released into river systems or directly into the ocean, where the carbon dioxide is durably stored. This process is known as engineered Enhanced Weathering (eEW).
By conducting EW in a closed system, key factors that influence the rate of reaction—such as temperature and pressure—can be directly controlled. It also allows for direct measurement of inputs and outputs of the reactor, including the amount of carbon dioxide stored.
Carbon dioxide removed from the atmosphere via a range of CDR technologies can be used under the Enhanced Weathering in Closed Engineered Systems Module, including DAC, Biogenic Carbon Capture & Storage and Direct Ocean Capture.
This module takes a scientifically rigorous approach to monitoring, reporting, and verification. It includes procedures and requirements for reactor design, environmental and social safeguards, and modelling of downstream losses of carbon dioxide.
The Enhanced Weathering in Closed Engineered Systems Module would require suppliers to meet three key requirements to ensure the durable storage of carbon dioxide:
- Provide comprehensive documentation of reactor design and maintenance.
- Take direct measurements of all inputs and outputs from the reactor.
- Robustly model the downstream losses of carbon dioxide once the bicarbonate ions are discharged and reach the ocean.
This module was developed in line with the Isometric Standard and was created in collaboration between Isometric’s in-house Science Team and reviewers from Isometric’s independent Science Network of over 300 scientific experts.
Leading eEW suppliers Capture6, Limenet, pHathom, Planeteers, and Vycarb provided extensive feedback during development of this module.
Comments on this module are welcome from interested buyers, suppliers, and scientists during the 30-day public consultation period, which ends on July 20.
