In Kenya’s Rift Valley, a pilot led by Cella Mineral Storage and Octavia Carbon has completed an early-stage underground CO2 injection, marking only the fourth known instance globally where direct air capture has been paired with geological storage in an integrated system.
The injection itself was modest at approximately half a tonne of CO2, but its significance lies in the system architecture rather than volume. The project combines atmospheric CO2 capture with in-situ mineralization in basalt formations, compressing what is often treated as a multi-step, infrastructure-heavy value chain into a localized operation. This approach contrasts with the prevailing hub-and-spoke model, where captured CO2 is transported via pipelines to centralized storage sites, typically requiring large-scale coordination and capital-intensive infrastructure.
The Kenya pilot also reflects an accelerated development timeline. According to project stakeholders, the system progressed from concept to field injection in under four years, a pace that underscores both the modular nature of emerging direct air capture technologies and the availability of transferable expertise from adjacent industries. The technical foundation draws heavily on subsurface engineering practices developed in oil and gas, particularly in injection and reservoir management.
At the core of the pilot is the adaptation of water-alternating-gas injection, a method traditionally used in enhanced oil recovery. In this case, the technique has been applied to basalt formations, which offer distinct geochemical advantages for long-term CO2 storage. When CO2 is injected into basalt, it reacts with minerals such as calcium and magnesium to form stable carbonates, effectively locking carbon in solid form. This mineralization pathway reduces long-term leakage risks that are often associated with conventional storage in sedimentary reservoirs.
Cella’s approach diverges from other basalt-based carbon storage models by injecting CO2 in a pure phase rather than fully dissolving it in water prior to injection. This distinction has operational implications. Fully dissolved CO2 systems require significant water volumes and complex pre-injection processing, which can constrain deployment in water-scarce regions. By contrast, the Kenya pilot reports lower water requirements while maintaining high injection rates, suggesting a potential pathway to improve the economics and geographic flexibility of mineralization-based storage.
The strategic framing of the project centers on decentralization. Rather than relying exclusively on large-scale storage hubs, the model envisions smaller, distributed storage systems located closer to emission sources or direct air capture units. This could be particularly relevant in regions where pipeline infrastructure is limited or where emissions are geographically dispersed. The concept of “boutique storage,” as described by project developers, challenges the assumption that carbon capture and storage must scale primarily through centralized megaprojects.
However, the scalability of this approach remains uncertain. While distributed systems reduce the need for transport infrastructure, they introduce complexity in permitting, monitoring, and verification across multiple sites. Ensuring consistent measurement of stored CO2 and long-term liability management becomes more challenging as the number of storage locations increases. Regulatory frameworks, which are often designed around large, centralized projects, may need to adapt to accommodate smaller-scale deployments.
Cost remains another critical variable. Direct air capture technologies are widely recognized as capital-intensive, with current cost estimates significantly higher than point-source capture. Pairing these systems with localized storage could reduce transport costs, but it does not address the underlying energy and material requirements of capturing CO2 from ambient air. The economic viability of such systems will depend on policy support, carbon pricing mechanisms, and the availability of low-cost renewable energy.
The Kenya pilot also highlights the role of geology in shaping carbon storage strategies. Basalt formations are widely distributed globally, including in regions such as East Africa, India, and parts of the United States. Their mineralization properties offer a different risk profile compared to conventional storage sites, but they also require site-specific characterization to ensure injectivity and reaction rates are sufficient for long-term storage.
