Engineered Closed-Loop Mineral Storage (ECLMS): A Conceptual Korean CCS Model Bridging Ex-situ Mineralization and Geological Storage

BongKwan Song , SeoYeon Kim 

The expansion of Carbon Border Adjustment Mechanism (CBAM) and the European Union's Emissions Trading System (EU ETS) has sharpened global expectations for permanence, traceability, and accounting integrity in carbon capture and storage (CCS). At the same time, several major industrial economies — including the Republic of Korea, Japan, and parts of Southeast Asia — face a structural deficit of natural geological storage reservoirs suitable for conventional CCS. Existing mineralization options, including ex-situ slurry reactors, in-situ basalt injection, and surficial mine tailings carbonation, occupy distinct niches but leave a regulatory grey zone for jurisdictions that lack large-scale saline aquifers yet possess abundant abandoned mine voids and alkaline industrial by-products. This perspective proposes Engineered Closed-Loop Mineral Storage (ECLMS) as a new conceptual CCS category. ECLMS combines (i) sealed underground containment in repurposed mine voids or engineered caverns, (ii) aqueous-phase mineral carbonation using slag, basalt, or olivine, and (iii) stabilization of CO₂ as dissolved bicarbonate (HCO₃⁻) and precipitated carbonates within a closed system. We map ECLMS onto the four IPCC trapping mechanisms, distinguish it from adjacent categories (Carbfix-style in-situ injection, Carbon8-style products, Calcarea-style ocean dispersal, and the Korean Dogye colliery pilot), and outline its compatibility with EU ETS Article 12(3b), Commission Delegated Regulation (EU) 2024/2620, the EU Carbon Removal Certification Framework (CRCF), the Article 6.4 Paris Agreement Crediting Mechanism (PACM), and the IPCC 2006 inventory guidelines. First-order capacity estimates for a 10,000 m³ reservoir suggest single-batch storage of approximately 2,250–6,900 tCO₂ (slag to olivine feedstock) and cumulative storage under semi-batch operation (Mode B) of approximately 4,500–21,000 tCO₂, with levelized costs in the range of USD 40–150 per ton of CO₂ stored. We argue that ECLMS is best understood not as a new technology but as a missing taxonomic category whose formal recognition would unlock CCS deployment in storage-deficit jurisdictions and complement, rather than compete with, existing pathways.