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Wärtsilä: Ammonia as marine fuel? It is easier if you do it smart

Technology group Wärtsilä explores the many sides of using ammonia as a bunker fuel including ammonia bunkering, main challenges, advantages and disadvantages.




RESIZED Wärtsilä Wartsila logo

Technology group Wärtsilä Corporation on Thursday (24 August) published an insight article explaining ammonia as a bunker fuel including operational considerations for ammonia.

The following are excerpts from the article:

Ammonia has emerged as a promising alternative as the shipping industry looks for more sustainable fuel options. This article explores the many sides of using ammonia as a marine fuel and provides insights on how to do it smart.

To meet the IMO’s target of net-zero greenhouse gas emissions by 2050, the shipping industry needs to move to cleaner fuels. There is no clear frontrunner among the several potential options, but ammonia offers some unique benefits that make it a leading contender. 

  • It doesn’t produce CO2, sulphur or particulate emissions when combusted.
  • A supply chain and infrastructure already exist for other applications.
  • It can be produced using renewable energy sources.
  • It is relatively easy to store and handle onboard ships.

But is it the right solution for your vessel? Read on to find out.

Ammonia as a marine fuel 

Is ammonia a viable fuel? Can ammonia be used as fuel?

Ammonia is an attractive alternative to fossil fuels for the shipping industry. It has the potential to 

significantly reduce greenhouse gas emissions, but there are still challenges to overcome. These include the development of a reliable ammonia fuel bunkering network and the fact that ammonia engines need additional maintenance because of the fuel’s corrosive nature.

Ammonia can be used as a gaseous or liquid fuel. Engines can burn this fuel well with minor adaptations.

What is ammonia’s fuel efficiency?

When it comes to ammonia fuel efficiency, the bottom line is it has a lower volumetric efficiency and energy density than diesel. Ammonia engines also have a lower efficiency than traditional fossil fuel engines. In short, a ship that uses ammonia needs much higher fuel storage capacity. The volume and weight of the storage infrastructure required also has a significant impact on the vessel’s operating range.

What are the main challenges when using ammonia to fuel ships?

There are three main challenges when using ammonia to fuel ships:

  • Ammonia is toxic, so the safety of the whole vessel must be considered, including the ventilation systems. 
  • When using ammonia, ships will need larger fuel storage capacity compared to diesel or LNG because ammonia has a lower volumetric energy density than both of these fuels.
  • Because ammonia is a new fuel, the regulatory landscape is still under development.

What are the advantages of ammonia as a marine fuel?

One of ammonia’s biggest advantages is that it doesn’t contain any molecular carbon, so when it’s combusted in an engine it produces no CO2 emissions. Adopting green ammonia as a maritime fuel is a great way to decarbonise shipping, helping to reduce the reliance on fossil fuels and move towards a more sustainable future.

Ammonia is abundant and can be produced using renewable energy sources such as wind and solar power. It is widely manufactured and traded, primarily for use in the production of fertilisers, and has the energy potential to be a viable marine fuel. 

Fuel storage and delivery systems don’t need to be overly complex when ammonia is used in its liquid form. This reduces the operating costs. 

Ammonia is already being used as fuel in power generation. 

What are the disadvantages of ammonia as a marine fuel?

Because ammonia is highly toxic and corrosive it requires careful handling and storage. However, the risks can be mitigated with proper crew training and equipment such as protective gear and ventilation systems. 

Ammonia doesn’t produce CO2 when combusted as fuel. The NOx emissions it produces can be handled with an abatement solution, and a wet scrubber system might be needed to manage potential ammonia gas releases. More investigation into these solutions, with the cooperation of classification societies, is needed.

One of the biggest unknowns with ammonia is how to handle potential N2O emissions. Catalysts are being developed for N2O – a potent greenhouse gas – to minimise N2O emissions and make ammonia a sustainable solution. For example, the Wärtsilä 25 ammonia solution with its optimised combustion and integrated aftertreatment has been designed to minimise all greenhouse gas emissions. 

For a quick overview of the advantages and disadvantages of ammonia as a marine fuel, you can download a handy one-page cheat sheet: Future fuel 101 – Ammonia 

Ammonia marine fuel safety 

How can ammonia be used safely as a marine fuel?

Ammonia has several safety issues related to toxicity, explosion risk and odours. Regulations are currently being developed to ensure ammonia can be used safely as a maritime fuel.

Three considerations are important to remember when it comes to ammonia fuel safety:

  • Ammonia is highly toxic and can be dangerous if not handled properly.
  • Ammonia requires specialised storage and handling equipment.
  • Ammonia fuel systems must be designed with safety in mind.

Wärtsilä is collaborating closely with classification societies to identify protocols and technologies to ensure ammonia is safe to use as a maritime fuel.

What do I need to consider when adopting ammonia as marine fuel? 

As the shipping industry moves towards decarbonisation, ammonia is emerging as a promising alternative fuel. To transition, your engine needs to be designed to use ammonia and specific materials need to be used for the components that will be exposed to the fuel. Using ammonia as marine fuel also requires significant changes in the engine room and the fuel-handling system. 

When building a new vessel, it is critical to consider what is needed to use ammonia as a fuel during the design phase. From a retrofit perspective, in order to safely bunker, handle and burn ammonia onboard, some of the existing vessel structures will have to be changed. New structures will need to be designed, assembled and built to create the necessary space to store ammonia onboard and transfer it to the converted engines. Auxiliary systems will need to be arranged to guarantee safely levels required by applicable rules and regulations. New auxiliary systems may also be needed, for example a drain system, bilge system, nitrogen system and ventilation system.

What will the ammonia fuel bunkering network look like?

The availability of ammonia as marine fuel, especially green ammonia, will be essential for reaching the marine industry’s decarbonisation targets. We are starting to see more discussions and investment decisions about an ammonia fuel bunkering network. This will scale up as the market starts to adopt ammonia.

Today, the demand for ammonia is mainly driven by fertiliser consumption, but the demand from the marine industry will start to increase as more vessels run on ammonia. DNV predicts ammonia use in shipping will be 170 PJ (1% of the shipping fuel mix) in 2030, 1,900 PJ (13% of the fuel mix) in 2040, and 5,000 PJ (36% of the fuel mix) in 2050.

The ammonia bunkering system can be fixed or mobile. Fixed bunkering involves stationary infrastructure at ports or fuelling stations, while mobile systems use transportable tanks. Ammonia can be stored as a liquid or a gas depending on the temperature or pressure.

Safety measures and environmental considerations play a critical role in the deployment of bunkering systems. 

Note: Wärtsilä’s full insight on ammonia as a marine fuel can be read here.

Photo credit: Wärtsilä
Published: 20 November, 2023

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Alternative Fuels

IUMI: How can liability and compensation regimes adapt to alternative bunker fuels and cargoes?

Existing international liability and compensation regimes do not fully cater to the changes that the use of alternative marine fuels will bring.





Dangerous cargo

By Tim Howse, Member of the IUMI Legal & Liability Committee and Vice President, Head of Industry Liaison, Gard (UK) Limited

The world economy is transitioning, with industries across the board seeking to reduce their carbon footprint and embrace more sustainable practices. As part of this, there is a huge effort within our industry to look to decarbonise, using alternative fuels such as biofuel, LNG, LPG, ammonia, methanol, and hydrogen.

Until now there has been much focus on carbon emissions and operational risks associated with the use of alternative fuels. This includes increased explosivity, flammability, and corrosivity. An ammonia leak causing an explosion in port could result in personal injuries, not to mention property damage, air, and sea pollution. In addition, alternative fuels may not be compatible with existing onboard systems, increasing the risk of breakdowns and fuel loss resulting in pollution. Apart from these safety concerns, which particularly concern crew, air pollution and other environmental impacts need to be addressed.

However, the green transition also presents us with a separate regulatory challenge, which has received less attention so far. So, whilst carbon emissions and safety concerns are rightly on top of the agenda now, the industry also needs to prioritise the potential barriers in the legal and regulatory frameworks which will come sharply into focus if there is an accident.

If anything, historic maritime disasters like the Torrey Canyon spill in 1967, have taught us that we should look at liability and compensation regimes early and with a degree of realism to ensure society is not caught off-guard. With our combined experience, this is perhaps where the insurance industry can really contribute to the transition.

Currently, existing international liability and compensation regimes do not fully cater to the changes that the use of alternative fuels will bring. For example, an ammonia fuel spill would not fall under the International Convention on Civil Liability for Bunker Oil Pollution Damage (Bunkers Convention), potentially resulting in a non-uniform approach to jurisdiction and liability. Similarly, an ammonia cargo incident would not fall under the International Convention on Civil Liability for Oil Pollution Damage (CLC). Uncertainties may also exist in the carriage of CO2 as part of Carbon Capture and Storage (CCS) projects, which may be treated as a pollutant, with corresponding penalties or fines.

A multitude of questions will arise depending on what happens, where it happens, and the values involved, many of which may end up as barriers for would be claimants. How will such claims be regulated, will there be scope for limitation of liability, and would there be a right of direct action against the insurers? In the absence of a uniform international liability, compensation and limitation framework, shipowners, managers, charterers, individual crew, and the insurers may be at the mercy of local actions. Increased concerns about seafarer criminalisation (even where international conventions exist, ‘wrongful’ criminalisation does still occur) may emerge, creating another disincentive to go to sea.

When being carried as a cargo, the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea (HNS), which is not yet in force, may resolve some of these issues for alternative fuels and CO2. However, until HNS comes into force, there will be no international uniformity to liability and compensation for the carriage of alternative fuels and CO2 as cargoes. This creates uncertainties for potential victims and their insurers, who may face increased risks and costs, due to the potential inability of existing regulations to provide protections.

The situation is even less clear in the case of bunkers. The rules for using alternative fuels as bunkers might require a separate protocol to HNS, a protocol to the Bunkers Convention, or a whole new convention specifically for alternative fuels.  Relevant considerations for the appropriate legislative vehicle include states’ preparedness to reopen the Bunkers Convention, the ability to conclude a protocol to HNS before it comes into force, and whether a multi-tier fund structure is needed for alternative fuels as bunkers (perhaps unnecessary because bunkers are usually carried in smaller quantities compared to cargoes).

Until then, what we are left with are the existing international protective funds, designed to respond at the highest levels to pollution claims resulting from an oil spill, without any similar mechanism in place to respond to a spill of alternative fuels, which are themselves so central to a green transition. Somewhat perversely, victims of accidents involving an oil spill may therefore enjoy better protections than victims of an alternative fuels spill.

In summary, while the use of alternative fuels will no doubt help to reduce the industry's carbon footprint, there are safety and practical hurdles to overcome. Stakeholders must also come together to find solutions to complex - and urgent, in relative terms - legal and regulatory challenges.


Photo credit: Manifold Times
Source:  International Union of Marine Insurance
Published: 13 June 2024

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Expert discusses technical considerations of using ammonia as marine fuel

Ammonia as bunker fuel poses significant safety challenges due to its toxicity and flammability, says ABS Regional Business Development Manager Muammer Akturk.





Technical considerations of ammonia as marine fuel

Muammer Akturk, ABS Regional Business Development Manager, on Monday (10 June) published an article on technical considerations of using ammonia as a marine fuel in his Alternative Marine Fuels Newsletter.

The article dives into the use of ammonia as a marine fuel, focusing on the safety and technical considerations necessary for its implementation.

Ammonia is recognised for its potential as a zero-carbon fuel, making it an attractive option for reducing greenhouse gas emissions in the shipping industry. However, it poses significant safety challenges due to its toxicity and flammability.

Key points discussed include:

  1. Safety Measures: The importance of stringent design and operational safety measures to prevent ammonia releases and mitigate risks during both normal and emergency conditions is emphasized. This includes the need for gas dispersion analyses and the use of safety systems like gas detectors and alarms
  2. Regulatory Framework: The article reviews the latest regulations and guidelines developed to ensure the safe use of ammonia as a marine fuel. This includes the IACS Unified Requirement H1, which provides a framework for controlling ammonia releases on vessels
  3. Engineering Considerations: Technical aspects such as fuel storage, handling systems, and the role of risk assessments in identifying potential hazards and implementing preventive measures are detailed
  4. Human Factors: The article also considers the human factors approach to safety, emphasizing training and the importance of designing systems that account for human errorOverall, the article aims to provide a comprehensive overview of the challenges and solutions associated with using ammonia as a marine fuel, highlighting the importance of safety and regulatory compliance in its adoption.

Editor’s note: The full article can be found at the link here.


Published: 13 June 2024

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SGMF study: Ammonia bunker fuel can cut shipping GHG emissions by up to 61%

Study, conducted by Sphera and commissioned by Society for Gas as a Marine Fuel, concluded that ammonia can ‘beyond question’ contribute significantly to IMO GHG reduction targets.





SGMF logo

An independent study has confirmed that greenhouse gas (GHG) reductions of up to 61% are now achievable from using ammonia as a marine fuel, depending on the marine technology employed. 

This figure is compared with the emissions of current oil-based marine fuels measured from well-to-wake (WtW). 

The 1st Life Cycle GHG Emission Study on the Use of Ammonia as a Marine Fuel from Sphera, a global provider of environmental, social and governance (ESG) performance and risk management software, data and consulting services, uses the latest available marine engine and supply chain data available to date.

The study, commissioned by Society for Gas as a Marine Fuel (SGMF), was conducted according to International Organization for Standardization (ISO) standards. It was also reviewed by a panel of leading independent academic experts from key institutions in France, Germany, and the USA. 

The analysis concluded that ammonia can “beyond question” contribute significantly to the International Maritime Organization’s (IMO) GHG reduction targets.

SGMF Chairman Tom Strang, said: “This is an important piece of work by SGMF that will help inform the maritime sector on the use of ammonia as a marine fuel and reinforces the importance of working together across all the different decarbonisation pathways, and for me highlights why we are part of SGMF”.

This comprehensive report uses the latest primary data to assess all major types of marine engines and global sources of supply with quality data provided by original equipment manufacturers including Wärtsilä, Winterthur Gas & Diesel & MAN Energy Solutions, but also Yara Clean Ammonia, and BASF on the supply side. 

GHG emissions from the supply chains as well as emissions released during the onboard combustion process (slip) have been included in the analysis.

Strang added: “It is important that an independent organisation like SGMF provides quality independent reports such as this latest life cycle assessment (LCA). The industry needs credible information and this is a landmark report as far as ammonia as a marine fuel is concerned.”

Mark Bell, GM for SGMF, added: “We are confident this work will provide IMO with solid information that will contribute to its regulatory decisions. SGMF will continue to produce up-to-date data, now including ammonia (this study), methanol and hydrogen.”

Dr. Oliver Schuller, director sustainability consulting at Sphera, said: “The main goal of this study was to provide a fact-based report describing the life cycle GHG emissions on the use of ammonia as a marine fuel across the value chain from well-to-wake. The analysis followed the established international standards ISO 14040/44 on life cycle assessment and underwent a critical review by three independent experts.”

Note: The full 1st Lifecycle GHG Emission Study on the Use of Ammonia as a Marine Fuel can be accessed from here.


Photo credit: Society for Gas as a Marine Fuel
Published: 11 June, 2024

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