Ship-based carbon capture: a bridge to carbon-neutral fuels

Cryogenic capture

“There is a massive amount of CO₂ emissions – about 1Bn tonnes from shipping,” said Mr Boyesen in discussing the two types of maritime carbon capture technology, amine and cryogenic. He called cryogenic carbon capture a “totally different technology,” that cools down the exhaust gas using heat exchangers in order to make the CO2 gas a solid.

Noting Denmark’s ambitious plans for reducing CO2 emissions from the transport sector, Mr Boyesen said: “There is going to be a need for carbon-containing fuels for the foreseeable future.”

Alluding to CCS supply chain development, he made the point that it would probably make more sense to produce these fuels using the CO2 captured as close to the emission sources as possible, to mitigate the costs involved in shipping it on CO2 carriers.

Mr Boyesen said MARLOG was working on a cryogenic carbon capture technology that could be used with existing fuels, MGO, HFO, LNG, biofuels or new fuels. He said the concept, decarbonICE, was to “freeze down the exhaust from ships and make it into CO₂ dry-ice torpedoes.” As they are heavier than water, these dry-ice torpedoes would be discharged overboard, where they would naturally sink to the seafloor, penetrating the sediments to be stored permanently, primarily as CO₂ hydrate.

CCUS’s role

Methanol has gained substantial attention in shipping, particularly following AP Møller-Maersk’s order for the first container vessel that will use carbon-neutral methanol as fuel when it begins operation in 2023.

GHG emissions can be avoided in the production of green methanol when made from biomass, waste streams and captured carbon dioxide emissions, making it a carbon-neutral or carbon-negative energy product.

Mr Chatterton said that according to The International Renewable Energy Association (IRENA): “The uptake of both bio and renewable methanol is set to grow substantially over the coming decades, with a considerable share of this methanol predicated on the use of carbon capture utilisation storage technology.”

“Dry-ice torpedoes would sink to the seafloor, penetrating the sediments to be stored permanently as CO₂ hydrate”

Noting the carbon footprint differences between gray, brown, blue and green fuels, Mr Chatterton said: “Direct carbon capture from the atmosphere comes with a separate set of challenges. Within shipping, as we move to assess fuels on a lifecycle assessment basis, CCU technology is going to be even more vital.”

In joining the conversation, Mr Baker discussed the rapid development of new technologies and the protection of intellectual property (IP): “A patent can be applied to any CCS, provided it is new or an improvement; an improvement need only be incremental, in terms of carbon capture efficiency, fuel efficiency or ease of use.” He noted a misconception, that IP slows down innovation and the introduction of new technologies, saying: “There’s absolutely no need for that to be the case.”

In his conclusions, Mr Boyesen said: “It was interesting to learn that there seems to be a broad consensus that we need a carbon tax in order to get things running.” The EU plans to include shipping in its EU Emissions Trading System (ETS) starting in 2023 and phased in over a three-year timeframe.

This was highlighted in a poll in which delegates were asked to choose the fuel they would prefer to burn if they were building a new handsize bulk carrier, factoring in the future implementation of an ETS or carbon tax: 51% chose LNG, with the possible integration with ship-based CCS, 20% chose methanol, with future use of bio-methanol and synthetic e-methanol, 15% said they would hold off and order either a zero-emissions hydrogen or ammonia-fuelled vessel, whichever comes first, and 15% voted for ordering a low-sulphur heavy fuel oil bulk carrier and paying future carbon taxes.

“When it comes to whether CCS can support the long-term climate goals, I would say that one positive thing is that it can be carbon negative,” said Mr Boyesen. He said if used in combination with green methanol, for instance, and if the carbon is captured, “you will actually be reducing the content of CO₂ in the atmosphere.”