Carbon dioxide utilization and storage through mineralization under European Union law: a legal analysis of the EU CCS Directive and the EU Emissions Trading System

Carbon dioxide mineralization—where captured CO2 is chemically converted into stable carbonates—offers a promising pathway for permanent sequestration and low-carbon material production. Situated between Carbon Capture and Storage (CCS) and Carbon Capture and Utilization (CCU), it challenges traditional legal distinctions while aligning with European Union (EU) objectives of climate neutrality by 2050. Yet, the EU regulatory framework has historically sidelined mineralization, focusing instead on geological storage. This article analyses the treatment of mineralization under the CCS Directive and the EU Emissions Trading System. It finds that the recent guidance by the European Commission allows the CCS Directive to cover in situ mineralization. However, for certain questions, it remains ill-adapted to the specificities of geochemical transformation, leaving uncertainties in permitting, monitoring, and liability. By contrast, recent reforms under the Emissions Trading System—particularly the Commission Delegated Regulation—explicitly recognize both calcium- and magnesium-based carbonates as valid forms of permanent storage, strengthening technological neutrality and providing clearer incentives. Through this legal analysis, the article argues that mineralization is transitioning from a regulatory lacuna to an increasingly integrated component of EU climate and energy law, but that further clarification, harmonization of measurement standards, and cross-regime coordination will be essential to unlock its full contribution to Europe’s decarbonization strategy.