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Hydrogen for marine power


Paul Turner examines the progress and potential of hydrogen propulsion in shipping and port operations, and the beginnings of the required infrastructure

CMB.TECH, the cleantech division of diversified Belgian shipping and logistics group CMB, has investigated a range of future fuel options comprising battery systems, LNG/CNG, synthetic fuels, biofuels, hydrogen, and ammonia.

In Maritime 2020 it was explained why CMB believed hydrogen was the best solution to meeting shipping’s zero-carbon goals. Hydrogen will form the basis for the decarbonisation of shipping, allowing renewable energy to be used far from shore. The renewable electricity from solar, tidal or wind is used to produce hydrogen (H2) by electrolysis, which can be stored under pressure, liquefied or combined with another chemical carrier, and used in a traditional engine to provide propulsion.

The company has been working on a roadmap to decarbonisation not only for its ships but also for the supporting port and logistic operations. There are three stages: dual-fuel engines, zero-emission monofuel engines, and fuel cells.

Step 1: Dual fuel

CMB’s Hydrobingo passenger ferry which began operating in Japan during 2021 – in time for the Tokyo Olympics. Photo: CMB

The programme developing hydrogen/diesel dual-fuel engines is well under way. The system is based on existing combustion engines which, with minor modifications, will be able to use hydrogen, thus reducing CO2 emissions by up to 98 per cent. It also reduces the particulate matter and NOx emissions to near zero.

However, this technology is not a magic bullet – the best results occur below half load, and reduce significantly at full load. Nevertheless, it provides a means for existing marine propulsion engines and equipment to reduce CO2 emissions well in advance of the net-zero 2050 target.

Dual-fuel technology will allow existing vessels with a 20–30-year life to meet the International Maritime Organization’s CO2 emission reduction requirements. Importantly, the technology will allow assets to work while the infrastructure is in its infancy, while providing infrastructure providers with a market.

CMB.TECH is working with four marine engine makers, and has engines available from 300 kW through to 2.7 MW. Three new vessels have been launched incorporating hydrogen technology, and a fourth is under construction.

The Hydroville, a passenger shuttle running between Kruibeke and Antwerp, has been in continual operation since 2016. CMB has invested in a multi-modal hydrogen refuelling station in the Port of Antwerp which provides hydrogen for this vessel and also for our logistics trucks, for our fuel cell cars and for port equipment.

The second vessel, the HydroBingo, an 80-person passenger ferry with two 13-litre diesel engines running on hydrogen, went into service in Japan this year, timed for the Tokyo Olympics. This vessel has received full Japanese approvals.

The third vessel, the Hydrocat crew transfer vessel, is undergoing sea trials. This vessel has been built by the CMB.TECH subsidiary Windcat Workboats to service offshore wind farms. The Hydrocat carries 200 kg of useable hydrogen, which will reduce diesel consumption by 600 litres a day, equating to 60–70 per cent of the vessel’s fuel requirements and 550 tons of CO2 a year. Further hydrogen-fuelled crew transfer vessels are being prepared, and the possibility of retrofitting existing vessels currently in service is being evaluated.

The Hydrocat will be UK-flagged, and CMB.TECH is working with the Maritime and Coastguard Agency for the approval of both the vessel and the bunkering process. Once sea trials are completed, the vessel will transfer to the UK register. CMB.TECH has also been working closely with Lloyd’s Register to obtain the classification approvals for the engine and hydrogen storage systems.

A fourth vessel, the Hydrotug, is under construction in Spain. It will go into service with the Port of Antwerp. This vessel will be fitted with two BeHydro engines, each with 2 MW of power. The vessel will carry 400 kg of hydrogen sufficient for daily operation at 80 per cent hydrogen.

Other vessels on the drawing board include pilot vessels, inland water vessels, coasters and large support vessels. Meanwhile, CMB.TECH has also engaged ports to develop service vehicles such as tractors, excavators, straddle carriers and even shunting trains.

Step 2: Zero emissions
monofuel hydrogen

CMB.TECH’s dual fuel powered truck. Photo: CMB

Dual-fuel technology will reduce CO2 and help build an infrastructure where hydrogen is available end to end. As soon as this infrastructure is up and running, the transition to the next step can take place. Operating a monofuel hydrogen engine at the correct air-to-fuel ratio will enable engines to generate power needs while producing no harmful emissions.

Hydrogen has no carbon elements within the fuel, so it produces no CO2 or particulate matter when burnt. If it is not managed carefully, however, it can produce NOx – and at rich mixtures, many times the NOx of traditional diesel engines. However, CMB.TECH has already developed strategies to operate the engines in a way that allows the power to be produced without producing any measurable NOx emissions.

CMB.TECH is currently providing small generators using hydrogen as the only fuel with no measurable engine-out emissions. As with any internal combustion engine, we do burn very small quantities of lubrication oil. With the hydrogen engine and the almost complete removal of combustion deposits combined with the lower peak pressure, CMB.TECH runs engines on bio-oil, thereby avoiding any CO2 impact by the oil consumption.

The initial introduction of the Zero Emissions hydrogen engines has been restricted to this lower power level because of the hydrogen supplies available. As the infrastructure for hydrogen supply builds, larger engines will be released.

The technology still requires more development to be able to service the wider applications that the diesel engine powers today. However, the science is well known, and wider roll-out only requires application rather than new research. What limits the zero emissions engines is the lack of infrastructure for the supply of hydrogen.

Step 3:  Hydrogen fuel cell

The hydrogen fuel cell offers great potential for a silent and zero-emissions propulsion system. However, its development is seriously compromised by its cost and complexity, and by the need for both high-purity hydrogen and an established end-to-end infrastructure. Even so, much can already be achieved using proven technology.

A solution for larger ships

Gaseous hydrogen will not be useable for larger oceangoing ships, so we are exploring the use of hydrogen carried by ammonia. This fuel avoids the problems generated by carbon-based fuels while benefiting from similar storage volumes of carbon-based e-fuels such as methanol. Ammonia is the combination of hydrogen with nitrogen, the nitrogen being extracted from the air; as nitrogen makes up the bulk of our atmosphere, its extraction is much easier and less energy intensive than that of CO2. The development of ammonia engines is ongoing.

What’s next?

CMB.TECH is working to consolidate the developments achieved to date. The dual-fuel technology is not fully zero, but with CO2 reductions at 70–80 per cent it is a significant improvement, and it comes at an affordable price. The technology is simple and safe, and is based on current operations.

Classification societies and government regulators must embrace innovation rather than resist change. It is essential that the risk-based design approach is used, as has been successfully managed to date.

Safety should always come first; however, restriction and control should be based on science and not on ignorance or myth. The rules around recertification of engines above 130 kW, if modified, need to be updated, in order to allow conversion ‘type approval’. This would allow existing ships to be retrofitted instead of waiting 20 years to rotate them out of service.

Above all, the dangerous application of LNG standards to gaseous hydrogen must be stopped because the basic principles of the gases are very different.  These two examples demonstrate the need for legislation to be updated to accord with progress.

Paul Turner is Managing Director of CMB.TECH. Willem van der Wel is Chief Executive of Windcat Workboats (part of CMB Group).