Lloyd's Register (LR) has released a publication titled "Applying Onboard Carbon Capture and Storage to Ships," adding a classification-society perspective to a debate over whether post-combustion CO2 capture can move from pilot projects to a global retrofit programme before the International Maritime Organization's 2050 net-zero target.

The document enters a regulatory environment that major classification societies — DNV, the American Bureau of Shipping, and Bureau Veritas among them — increasingly shape through their rule sets. Shipowners cannot insure, finance, or commercially flag a vessel with an unclassed OCCS retrofit.

What OCCS asks a ship to do

Onboard carbon capture pulls CO2 from a vessel's exhaust, compresses it, and stores the liquid in tanks fitted to the hull or deck. The vessel offloads the captured CO2 at port to a reception facility for transport and permanent sequestration or utilisation. Onshore CCS operators manage a fixed plant; a ship has to do it under vibration, list, and limited space.

LR's guidance asks whether capture equipment, heat integration, intermediate storage, and offloading interfaces can meet class-survey conditions on a commercial hull.

The regulatory clock

Three policy tracks now shape owner decisions on OCCS investment:

• IMO 2050 net-zero target, with intermediate greenhouse-gas checkpoints adopted in 2023 under the Revised GHG Strategy.
• FuelEU Maritime, the EU regulation that entered force in 2025 and tightens the greenhouse-gas intensity of energy used by ships calling at EU ports.
• EU ETS extension to maritime, which prices emissions on voyages to, from, and between EU ports.

Each track changes the math on a system that adds capex, weight, and a port-side handling chain. OCCS lets a vessel continue burning conventional fuel while lowering the carbon intensity of the energy it uses — a profile that fits FuelEU's intensity accounting better than older offset models.

What to watch

The next milestones for OCCS sit in the document trail, not at the dock. Class societies, including LR, are processing Approval in Principle (AiP) applications from engine makers and system integrators. The first AiP for a marine OCCS unit would convert the technology from pilot to bankable.

After AiP comes class approval for a specific vessel installation, then a commercial-scale sea trial with shore-based CO2 handling. Class work typically runs 12–24 months per step, which puts broad fleet deployment beyond the back end of this decade unless regulators force the issue.

Port-side CO2 reception infrastructure is the limiting factor. A captured tonne counts as a credited tonne only once a port can receive, transport, and sequester it. Rotterdam, Antwerp, and the Nordic ports have published roadmaps; most others have not.

The IMO's MEPC session later this year, and the next revision of the Revised GHG Strategy, will signal whether onboard carbon capture is treated as a transitional compliance tool or a long-term option. Lloyd's Register's entry into the guidance space indicates the former for now: a tool that buys time while fuel-switching infrastructure catches up.