Clean fuels can’t leapfrog clean technologies

There is a danger that focusing entirely on new fuels. The maritime industry must remain focused on energy efficiency and sustainable propulsion technologies, says Simon Potter, director of sustainability advisory at Houlder.

While the environmental ambition is laudable, unintended consequences of the IMO’s decarbonisation regulations appear to be emerging.

Regulations such as the Carbon Intensity Indicator are encouraging the majority of shipowners and operators to limit the power of vessel engines to reduce emissions and then wait for alternative fuels to emerge at scale rather than invest in the plethora of clean technologies available today.

This is detrimental to progress. Future fuels will be expensive and less energy-dense than current fuels. Energy-saving clean technologies will be needed for their commercial viability, so the two pathways to reducing emissions aren’t mutually exclusive or even distinct from each other.

They are mutually beneficial. The key challenge remains reducing vessels’ energy requirements while providing the energy needed to operate as cleanly and efficiently is possible. Once fitted, clean technologies add favourably to the return on investment of adopting new fuel technologies later on. They also lessen the risk of adopting new fuels and their associated new technologies.

This is important because a wide range of solutions will be needed to support the diversity of the international fleet as it transforms to meet long-term IMO and EU targets. New fuels cannot leapfrog over clean technology development, they are dependent on them.

Inter-dependent systems

An example will demonstrate this point best. Houlder recently completed a feasibility study for a newbuild zero-emission service operation vessel.

A general arrangement for a vessel fuelled with liquid organic hydrogen carrier (LOHC) and powered by proton-exchange membrane fuel cells was successfully demonstrated. The concept vessel produces zero-emissions in operation (tank-to-wake) and a preliminary high-level estimate showed a lifecycle (well-to-wake) CO2e emissions reduction of 83%.

The vessel is fitted with a redundant Energy Storage System (ESS) in the form of Lithium-ion batteries. In addition to the power provided by the fuel cells, these batteries were sized to meet the vessel’s power demand at maximum speed. The batteries also compensate for the slower transient response of the fuel cell system.

The inter-dependence of new fuel and new technology is clear. The success of LOHC is dependent on the fuel cell technology, which is in turn dependent on the ESS. A serviceable vessel requires the three to work in unison.

The success of LOHC is dependent on the fuel cell technology, which is in turn dependent on the ESS.

The realisation of such a vessel is still some years away. Before it can become a reality, LOHC release units must become commercially available, green hydrogen production must scale up, the cost of an LOHC-fuelled vessel must be addressed, and more prescriptive regulations for hydrogen fuelled vessels must be developed.

However, innovative vessel designs such as this highlight any barriers to technology adoption and can help the industry overcome them. Further developing this vessel would make decarbonisation through LOHC more of a known quantity – tackling technical challenges, supporting investment, and informing regulations.

The experience the industry has already gained with energy saving devices such as ESS reduces the technical risks and lessens the lead time for futuristic designs such as this.

Technical advice

Shipowners are increasingly seeking technical advice on decarbonisation projects that fall outside of their usual experience. Consultants will play an important role.

Analysing the greenhouse gas emissions and carbon intensity of the current fleet and its operations is key before identifying the most suitable technologies and operational measures to reduce carbon emissions. This includes defining the costs, benefits, and timeline for implementation of these technologies.

The specific operational challenges faced by each vessel type will also all need to be analysed before identifying the best solutions.

The fuel consumption of vessels in different operational modes, as well as total annual consumption, need to be calculated and the impact of anticipated changes to the construct of the fleet must be considered over the next 10 years. All this analysis is needed to target the most effective technical and operational improvement measures.

As well as the vessel’s operational requirements, the viability of each solution must be considered in line with available space, displacement, power demand and endurance requirements.

Engine power limitation works, but is a pessimistic approach and doesn’t complement the adoption of alternative fuels.

Analysis should also evaluate the associated implementation costs alongside the resulting fuel efficiency and emissions savings to ensure shipowners and operators get a strong cash and carbon return on investment.

Finally, forecasting a fleet's greenhouse gas emissions through the next 10 years for different investment scenarios will help shipowners and operators prioritise and properly plan for the implementation of clean technologies.

Consideration must be given to timescales for engineering, procurement, and installation of technologies as well as vessel operational demands and dry-docking schedules in order to be successful.

The bottom line is that there are many proven energy efficiency and renewable propulsion adaptations and technologies that can be deployed on vessels in operation today to support the transition to net-zero carbon emissions. Engine power limitation works, but is a pessimistic approach and doesn’t complement the adoption of alternative fuels; clean technology does.