EU Accepts Mineralized CO2 Storage for Onboard Carbon Capture

EU Recognizes New Disposal Route for Captured Shipboard CO2

According to a report by The Maritime Executive, the Singapore-based Global Centre for Maritime Decarbonisation (GCMD) has achieved a regulatory milestone for onboard carbon capture and storage (CCS). The European Union has agreed to recognize onboard-captured carbon as compliant with the EU Emissions Trading System (EU ETS), provided the CO2 is converted into a chemically bound, mineralized form within an approved product rather than simply stored or vented.

This decision was informed by a 2025 test campaign that GCMD conducted, and it gives shipowners calling at European ports a potential cost-saving pathway for handling captured emissions.

How the Test Worked

The trial was carried out on the 18,000 TEU Evergreen containership Ever Top, which had been retrofitted in 2024 with a carbon capture system developed by China State Shipbuilding Corporation (CSSC). While the vessel was berthed at a port in China, the system achieved a gross capture rate of roughly 11 percent, producing CO2 at a purity of 99.95 percent — a quality level suitable for commercial use.

After being offloaded, the captured carbon was sent to a steel slag processing facility, where it was converted into calcium carbonate, a stable mineral compound used across various industries. This mineralization step is central to the new EU approval, since it transforms the captured gas into a solid, non-volatile product rather than requiring long-term liquid or gaseous storage.

Regulatory Momentum Builds on IMO Groundwork

GCMD and its partners shared these results with both EU regulators and the International Maritime Organization. The EU’s acceptance of mineralized CO2 as an ETS-compliant outcome builds on earlier progress at the IMO, which granted in-principle approval for this disposal method at MEPC 84 — adding to existing acceptance of geological storage, where CO2 is injected underground.

Prof. Lynn Loo, CEO of GCMD, said the EU ETS deduction gives captured carbon a defined compliance value, while the IMO’s in-principle backing for mineralization helps establish a clear pathway for what happens to CO2 once it leaves the ship. Taken together, she noted, these developments convert what was a pilot project into a validated reference case for maritime carbon logistics — connecting regulatory recognition, commercial value, and measurable emissions reduction.

What This Means for Owners and Operators

For ship operators evaluating onboard CCS retrofits, this development addresses one of the technology’s biggest unresolved questions: what actually happens to the captured carbon after it comes off the vessel. Until now, much of the industry conversation around onboard capture has focused on the capture hardware itself and the energy penalty it imposes, while the downstream disposal and verification chain remained murky. A recognized, EU-compliant mineralization pathway gives owners a tangible framework for turning captured CO2 into a documented, tradeable compliance asset rather than an operational liability requiring specialized storage tanks or geological injection infrastructure.

That said, the 11 percent capture rate recorded in the test is a reminder that current onboard CCS technology captures only a fraction of a vessel’s total emissions, meaning it is likely to function as one tool among several — alongside alternative fuels and efficiency measures — rather than a standalone decarbonization solution in the near term. For technical superintendents and surveyors, the emergence of a verified disposal chain also raises new inspection and documentation questions: confirming capture system performance, purity standards, and custody of the CO2 through offloading and processing will likely become part of due diligence for any vessel fitted with these systems, much as bunker quality and quantity verification is already routine practice in survey work today.

As more owners consider retrofitting vessels with carbon capture equipment, clear chain-of-custody verification — from onboard capture through to final mineralization — will be essential to ensuring that compliance claims under frameworks like the EU ETS hold up to scrutiny.

Reviewed by Ibrahim Halil Ceylan, Marine Surveyor at Apeks Marine.