In an interview with Maritime Fairtrade, Edwin Khew, chairman of the Sustainable Energy Association of Singapore (SEAS), deconstructs the profile of different alternative fuels and how decarbonization progress can be pushed ahead.
If only transitioning to a green business was cut and dry, the voyage to zero carbon would be smooth and sailing forward. However, the complex and intricate operations fitted to individual stakeholder test feasibility, profitability and practicality to the limit.

Edwin Khew, chairman of the Sustainable Energy Association of Singapore (SEAS). Photo credit: SEAS
What do you think could accelerate hydrogen’s adoption and production?
Green hydrogen is a promising alternative fuel, but its widespread adoption in Singapore is hindered by production cost. It is currently at circa S$5/kg and needs to be at $1/kg. In addition, supply limitations, such as metal embrittlement, and the inability to transport at scale are other issues.
To accelerate its adoption, government incentives and policies encouraging research and development, together with public-private partnerships, will play a pivotal role in reducing the cost of green hydrogen production, thus making it more economically viable.
What is hindering stakeholders from turning to hydrogen and hydrotreated vegetable oil (HVO), as compared to ammonia?
Shipowners and businesses in Singapore face several challenges when considering hydrogen and HVO over ammonia as carbon-free fuels.
For green hydrogen, other than cost, there is a lack of competitive energy converters. Fuel cells are not large enough for propulsion of large marine vessels. Smaller harbor crafts are most likely for first adopters but at a high price. So, unless incentives are in place, adoption will be slow.
Furthermore, although hydrogen distribution systems exist in Singapore for targeted industrial users, it has not been fully established for more ubiquitous access. As it is costly and cannot be easily passed on to the consumer, its adoption is hindered. One of its safety concerns includes its high flammability, especially when handling and distributing hydrogen at scale.
As for HVO, which is a paraffinic fuel, it is only compatible with diesel and not with heavy fuel oil, which is the majority volume of maritime fuel. So, compatibility is limited to marine gas and diesel oils. Cost remains high, which is potentially recoverable from customers of the airline industry and not the maritime industry.
However, policy compliance may result in some adoption of HVO in pilot fuels for dual fueled engines burning heavy fuel oil and ammonia. Current fuel delivery infrastructure is generally compatible with HVO.
As for ammonia, while it has a long history of being handled at scale in the industrial sector, the availability of green ammonia is currently too limited to be a low carbon fuel alternative. Furthermore, there are no large (2-strokes) ammonia engines available in the market as yet.
While recent commercial development of 4-strokes engines by IHI, Wartsila and CMB-Tech shows promise, the key assets along the marine fuel delivery system, such as ammonia bunkering vessels, have yet to be specified and built.
In addition to that, the toxicity exposure risks of ammonia while being handled as a marine fuel needs to be managed with tight safety processes and crew training before confidence levels can pave the way for its adoption.
Why are some shipping companies struggling with green transition?
Whilst the International Maritime Organization (IMO) and many port authorities have indicated decarbonization targets over the next three decades, most shipping companies are taking a wait-and-see approach with respect to green alternative fuels. This is primarily due to uncertainty of availability at specific ports of call, the trade patterns of the vessels, the inability to pass on the higher cost to consumers, and the lower volumetric energy densities of the alternative fuels which require either more bunkering ports or larger storage tanks resulting in lower cargo space.
Interestingly the adoption of energy efficiency technologies is not ubiquitous either due to commercial complexities, namely split incentives between the owner and the charterer, and the confidence in the performance improvement of these technologies to unlock green financing.
The heterogeneity of shipping vessels in terms of size, energy load profiles, routes, cargo type, commercial contracts and port readiness also creates complexity in identifying the most appropriate decarbonization pathway for each vessel in the fleet.
Regulatory uncertainties and the lack of standardized global regulations on emissions and sustainability also add to the complexity. Additionally, there is often a skills gap in the workforce, with a need for more trained personnel to operate and maintain new green technologies.
Efforts by the Global Maritime Forum, Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping and others are helping the industry solve these conundrums.
These challenges, as well as energy efficiency, regulations and decarbonization, are some of the topics we hope to discuss and seek solutions at this year’s Asia Clean Energy Summit (ACES) 2024, which is set to return for its 11th year with a new edition of the Asia Carbon Summit, highlighting the pivotal role that carbon makers play in the transition to clean energy. It will be focused on reshaping and realigning net-zero objectives to meet the growing demands of climate change migration, national and corporate commitments – all in the bid to achieve carbon neutrality.
What are the highest risks in achieving decarbonization in Singapore’s context and how to navigate them?
The highest risk in achieving decarbonization (zero emission shipping) is the availability of and accessibility to cost-competitive green alternative fuels, which is dependent on low-cost green hydrogen as its feedstock (green ammonia, green methanol). Furthermore, biofuels availability which is cost effective at scale (FAME, straight vegetable oils, HVOs and other generation-3 bio-based fuels) are also options.
In the context of Singapore, for domestic shipping, the Maritime & Port Authority of Singapore (MPA) has clearly articulated a domestic decarbonization roadmap with firm targets that serve as a guide for the local industry.
As for international shipping, driven by IMO policies, Singapore is preparing itself to serve as a multi-bunker fuel port running pilots in methanol bunkering, FFI ammonia shore to vessel transfer and biofuel bunker proof of sustainability requirements. MPA chairs the IMO council working group responsible for developing its strategic plans from 2024 to 2029, and holds the vice-chair position at the Marine Environment Protection Committee (MEPC).
Photo credit: Pixabay/ AndreasAux