GCMD Ships Onboard Carbon Capture Impact Calculator for Maritime

The Global Centre for Maritime Decarbonisation (GCMD) has launched an Onboard Carbon Capture and Storage (OCCS) Impact Calculator, a new tool aimed at helping shipping stakeholders quantify what capturing CO2 aboard vessels could actually deliver.

The announcement, reported by Manifold Times, puts a concrete instrument into a debate that has so far run mostly on projections. Shipowners, operators and fuel buyers now have a named calculator they can point to when weighing OCCS against other decarbonisation routes.

What is GCMD actually shipping?

GCMD — the maritime decarbonisation centre established in Singapore with backing from the Maritime and Port Authority of Singapore and industry partners — has built its reputation on convening pilot projects and trials across alternative fuels and emissions-reduction pathways. The Impact Calculator extends that work into onboard capture, one of the more contested corners of maritime decarbonisation.

Onboard carbon capture asks a vessel to trap its own CO2 exhaust, store it in some form onboard, and offload it shoreside for sequestration or reuse. It sounds straightforward. It is not. The equipment adds weight, eats cargo space, consumes energy that would otherwise push the ship, and creates an offloading problem at port that most ports have not solved.

A calculator does not fix any of that on its own. What it does is force the conversation onto numbers — the only place, on this desk's view, where it belongs.

Why does a calculator matter to the material stream?

Here the story touches Circular Wire's core beat. Captured CO2 is not waste in the ordinary sense; it is a feedstock question. If OCCS scales, ports and receiving terminals will need infrastructure to take CO2 off ships and route it into storage sites or into utilisation chains — mineralisation, synthetic fuels, industrial gases. That is built capacity that mostly does not exist yet, announced project by announced project.

So the calculator sits upstream of a infrastructure question: if vessels start landing captured CO2 at scale, who builds the receiving end, and under which permits?

Takeaway in plain words: a tool that measures capture potential is the first step toward knowing how much CO2 offloading infrastructure ports will eventually have to plan for.

Who uses it, and to what end?

The tool targets the standard OCCS decision set: which vessel types and trading patterns make capture worth the retrofit, how the energy penalty weighs against compliance value, and how results compare with alternative fuels. GCMD's framing, per the Manifold Times report, is impact — meaning output expressed in terms decision-makers can act on rather than raw engineering data.

For an industry staring down tightening carbon-intensity rules from the International Maritime Organization, the comparison matters. Owners are allocating capex across fuels, retrofits and efficiency measures now. A calculator that ranks OCCS honestly against those options either accelerates adoption or kills it early. Both outcomes are useful.

Takeaway: the value of the tool is not the number it prints, but the decisions it forces.

What happens next?

Watch for two things. First, uptake — whether shipowners and technical managers actually run their fleets through the calculator and publish what they find. Second, the infrastructure response: any port operator or terminal group that cites OCCS projections when justifying CO2 receiving and transfer investment.

The milestone that decides what happens next is regulatory: how the IMO's greenhouse-gas framework and national storage-permit regimes treat captured shipborne CO2. Until that settles, the calculator is a planning instrument, not a commitment mechanism.