Maersk, Lloyds Register promote ethanol, biomethane as net zero fuels for shipping

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A new study carried out by shipping line A. P. Moller – Maersk and classification society Lloyds Register has confirmed that the best way to decarbonise shipping is to find new sustainable energy sources.

Based on market projections, the best positioned fuels for research and development into net zero fuels for shipping are alcohol (ethanol and methanol), biomethane and ammonia. Reaching net zero, however, requires a fundamental shift in the way that deep sea vessels are propelled, and the industry must introduce carbon neutral propulsion fuels and new technologies.

“The main challenge is not at sea but on land,” said Søren Toft, COO of Maersk. “Technology changes inside the vessels are minor when compared to the massive innovative solutions and fuel transformation that must be found to produce and distribute sustainable energy sources on a global scale. We need to have a commercially viable carbon neutral vessel in service 11 years from now.”

The three fuel pathways – alcohol, biomethane and ammonia – have similar cost projections, according to the study, but have different challenges and opportunities.

“It is too early to rule anything out completely, but we are confident that these three are the right places to start,” Toft continued. “Consequently, we will spend 80% of our focus on this working hypothesis and will keep the remaining 20% to look at other options.”

Alastair Marsh, CEO of Lloyds Register, added: “The next decade requires industry collaboration as shipping considers its decarbonisation options and looks closely at the potential of fuels like alcohol, biomethane and ammonia. This joint modelling exercise between Lloyd’s Register and Maersk indicates that shipowners must invest for fuel flexibility and it is also clear that this transition presents more of an operating expenditure rather than capital expenditure challenge.”

Fuel pathways

Alcohols, which include ethanol and methanol, have various possible production pathways, including directly from biomass and/or via renewable hydrogen combined with carbon from either biomass or carbon capture. Ethanol and methanol are fully mixable in a vessel’s bunker tanks, which creates bunkering flexibility. However, the transition of the industry towards alcohol-based solutions is yet to be defined.

On the other hand, biomethane has a potential smooth transition thanks to existing technology and infrastructure. The challenge here is methane slip, which is the emission of unburned methane throughout the supply chain.

In the case of ammonia, this is a truly carbon-free fuel that can be produced from renewable electricity. The energy conversion rate of this system is higher than that of biomaterial-based systems, however the production pathway is unable to use potential energy sources such as waste biomass. The main challenge for ammonia is that it is highly toxic.