Singapore prepares for electric vessels, multi-fuel future

Fuel cells

Also in Singapore, Vallianz Holdings is working to build its first electric-powered tugboat and is considering using technology to increase the range of future vessels.

It has naval architecture for a battery-powered tugboat with a bollard pull of around 30 tonnes but might increase this to 50 tonnes with another design, and potentially use swappable batteries.

Also on the horizon for the Singapore owner is operating a vessel with a hydrogen fuel cell combined with batteries. Vallianz head of engineering Wu Shengwei says electro-chemical engines could be propulsion solutions in the long term due to their higher energy efficiency.

“Fuel cells are getting more attention,” he says. “They burn low, or zero-carbon fuels with no emissions, low vibration and maintenance. They enable vessels to operate a longer distance for higher endurance.”

Fuel cells have an energy efficiency of 60% versus 45-50% of diesel engines. With heat-return, system efficiency is increased to 80-90%, says Mr Wu. He adds the most popular fuel cells involve proton-exchange membranes (PEM).

Around 20 vessels of various types are operating with fuel cells, and this is expected to rise to 37 in 2025, including 28 with PEM units, he forecasts. These are providing varying levels of energy on vessels including dredgers, tugs, workboats and offshore support ships.

“PEMs are mainly used due to them having operational flexibility, a lower size and weight, higher levels of development, and less system complexity and maintenance than others,” says Mr Wu. The other types are solid oxide fuel cells and molten carbon fuel cells – both still in early development and testing.

When PEM fuel cells are applied to harbour tugs, they would be part of an integrated power and propulsion system with batteries and a hydrogen fuel source, such as ammonia or compressed tanks, with a DC grid and DC-AC converters and a power management system.

Ammonia-fuelled tugs

In the US, Amogy has started using ammonia fuel to generate hydrogen to feed into a PEM fuel cell on tugboat NH3 Kraken, which was converted from a 1957-built vessel at Feeney Shipyard in Kingston, New York. 

It first sailed on a tributary of the Hudson River on 22 September with Amogy’s ammonia cracking unit and fuel cell on board. Ammonia holds more energy than hydrogen and is easier to store and bunker, but it is toxic and pungent.  

Amogy chief executive Seonghoon Woo says NH3 Kraken is a step towards demonstrating ammonia cracking technology for future applications on larger ships. 

“Governments across the globe and industry organisations like IMO have set aggressive goals to reduce global carbon emissions,” says Mr Woo. These goals seem daunting, but they are necessary – and our successful demonstration of the world’s first carbon-free, ammonia-powered vessel proves they are achievable.”  

During this demonstration, NH3 Kraken is fuelled with green ammonia, produced entirely with renewable energy, further reducing its carbon footprint. This is stored in a 9,100-litre tank fitted inside the old fuel tank space, giving it enough energy to sail 10-12-hours per day at sea. Amogy has already tested its ammonia cracking technology on a lorry, tractor and aerial drone. 

“We have gained invaluable knowledge that will help us move quickly to commercialisation and deploy real-world applications,” says Mr Woo. “The opportunity to decarbonise the maritime industry is within reach, and for Amogy, [NH3 Kraken] is just the beginning.”

Amogy is working on contracts with organisations covering potential retrofit and newbuild projects. South Korean shipbuilder Hanwha Ocean is purchasing its technology and HD Hyundai and Samsung Heavy Industries are working with Amogy on ship designs. 

Amogy intends to release a case study providing additional technical details in the coming months.

In Japan, NYK and IHI Power Systems Co completed ammonia-fuelled tugboat Sakigake, in co-operation with ClassNK, and it entered commercial operation in Tokyo Bay on 23 August. NYK Group’s Keihin Dock Co converted the 2015-built LNG-fuelled tugboat of the same name for ammonia fuel, with the main engines and fuel-handling system replaced for the new fuel. During Q3 2024, Sakigake underwent sea trials on ammonia fuel, demonstrating safe bunkering and operations on this toxic fuel. During the rest of this year, NYK’s Shin-Nippon Kaiyosha will employ this vessel in tugboat operations in Tokyo Bay over a three-month demonstration period.

This investment was part of the Green Innovation Fund Project, initiated in October 2021 under Japan’s New Energy and Industrial Technology Development Organisation, to develop vessels equipped with domestically produced ammonia-fuelled engines.

Under this project, NYK is also conducting research and development on an ammonia-fuelled medium gas carrier with Japan Engine Corp, Nihon Shipyard Co, IHI Power Systems and ClassNK. This vessel is scheduled for delivery in November 2026.

Sustainable biofuels

In Canada, Ocean Group is taking another step towards greener operations by adopting hydrotreated vegetable oil (HVO) renewable diesel fuel for all its towing operations in ports in British Columbia.

Its supply of HVO is made from renewable sources, including vegetable oils, residues of plant or animal origin and used oils such as those derived from frying.  

This fuel has the major advantage of reducing lifecycle CO2 emissions by around 80% compared with traditional fossil fuels, cutting the vessel owner’s carbon footprint.

It has been testing HVO at its Delta Port and Fraser River sites since 2023 and has secured the necessary authorisations from Transport Canada. “After months of data analysis and obtaining the authorisation, we are ready to finalise the transition to this environmentally friendly fuel by the end of 2024,” says Ocean Group.

“Eventually, all Ocean Group tugs in British Columbia will be powered by this sustainable energy source, marking a decisive turning point in our company’s environmental strategy. This change is not just a technical initiative.”

It is part of a wider strategy that underlines the owner’s commitment to reducing the ecological footprint of its marine activities. It comes with the backing of Musqueam Capital Corp, Ocean’s partner on the Fraser River and the Musqueam territory.

This agreement included training members of the Musqueam community in maritime-related jobs and creating career opportunities.