A study by A.P. Moller - Maersk and Lloyd's Register indicates that the best opportunities for decarbonizing shipping lie in finding new sustainable energy sources, in particular: alcohol, biomethane, and ammonia.
The study has found that the cost of transport will rise – not because ships themselves will require greater levels of investment but because new fuels are projected to be significantly more expensive than existing fossil solutions which will lead to increased operating costs.
“Decarbonising shipping requires a total shift in propulsion technologies, and by 2030 we need to see the first commercially viable carbon neutral vessels in service – that’s only 11 years from now. This is a game changer that requires close collaboration and joint action from researchers, regulators, technology developers, investors, customers and energy providers,” says Søren Toft, Maersk Chief Operating Officer.
“The main challenge is not at sea but on land,” he says. “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 proposed fuel pathways have relatively similar cost projections but 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. Consequently, we will spend 80 percent of our focus on this working hypothesis and will keep the remaining 20 percent to look at other options,” says Toft.
The modeling indicates that shipowners must invest for fuel flexibility, and the transition presents more of an operating expenditure rather than capital expenditure challenge.
Alcohols (ethanol & methanol) are not highly toxic and have various possible production pathways - directly from biomass and/or via renewable hydrogen combined with carbon from either biomass or carbon capture. Existing solutions for handling the low flash point and for burning alcohols are well proven. Ethanol and methanol are fully mixable in the vessel’s bunker tanks, creating bunkering flexibility.
However, the transition of the industry towards alcohol-based solutions is yet to be defined. Biomethane, on the other hand, has a potential smooth transition given existing technology and infrastructure. The challenge however is methane slip – the emission of unburned methane along the entire supply chain.
Ammonia is carbon free and can be produced from renewable electricity. The energy conversion rate of this system is higher than that of biomaterial-based systems, but the production pathway cannot tap into potential energy sources as e.g. waste biomass. The main challenge for ammonia is that it is highly toxic, and even small accidents can create major risks to the crew and the environment. The transition from current to future applications is also a huge challenge for ammonia.
According to Maersk and Lloyd's Register, batteries and fuel cells are unlikely to have an immediate role in propelling commercially viable carbon neutral deep-sea vessels.
A further key conclusion is the recognition that the market will not drive the transition to zero, and policy interventions as well as a fundamental change to the incentives scheme for shipping are required.