Onboard carbon capture no more than a ‘transitory’ fix
DNV estimated capture rates from an LNG carrier of 11%-38%, which may make the cost hard to justify
Jesse Fahnestock of the Global Maritime Forum is sceptical of onboard carbon capture in the long term. DNV believes the technology has potential if it can become cheaper and carbon more expensive
ONBOARD carbon capture and storage of CO2 is only a temporary fix for shipping’s greenhouse gas emissions, according to the Global Maritime Forum’s decarbonisation director.
Jesse Fahnestock pointed to a recent DNV feasibility study that found CO2 reductions from OCCS of 11%-38% from an LNG carrier, depending on the technology used.
He contrasted this with earlier modelling of capture rates of an estimated 70%-75%.
Fahnestock said that by 2040, the average ship would need to cut its CO2 emissions by 90% to align with the International Maritime Organization’s greenhouse gas strategy, citing a brief by GMF and Umas in January.
He said it was difficult to reconcile the cost of OCCS with the lower estimated capture rate.
“So CCS is only a transitory option, as far as I can see,” he said.
“And given the likely complexities of the storage value chain, one has to wonder whether the timing of the solution fits the timing of the IMO strategy.”
The study suggested OCCS would cost about the same as using biofuels per tonne of CO2 abated, making it cheaper than using e-fuels (the most expensive, zero-carbon type made from renewable electricity).
But trapping a ship’s CO2 emissions on board is energy intensive, and this “energy penalty” becomes worse the more carbon you capture.
DNV’s modelling of an 174,000 cu m LNG carrier starting service in 2025 showed that capturing 70% of the carbon had an energy penalty of 30%, voiding its business case.
Ships will also need somewhere on shore to deposit the carbon scrubbed from their smokestacks.
DNV said the maritime industry would greatly benefit from “a more mature CCS technology”. A better-performing system with more powerful CO2 solvents would greatly improve the business case, it added.
“CCS hubs are planned or being built at many ports; however, for CCS to succeed, low offloading costs are crucial and should be ensured by governments as part of their national decarbonisation strategies,” DNV said.
The business case would improve if fossil fuel prices were low and biofuel prices high; DNV’s modelling showed a favourable case in this scenario, even with a 70% capture rate.
In this case the technology could help shipowners hedge against fuel price fluctuations.
“If biofuel becomes very expensive or is in short supply, CCS will immunise the operator by providing the option to use fossil fuel,” DNV said.
