Future fuels A to Z – 19 best picks on future marine fuel technology

The 19 best picks on marine future fuel technology to help you comply with regulations, save money and hit your decarbonisation targets in a handy A-Z.

From ammonia to zero-emission energy distribution, here is a rundown of the 19 best picks on marine future fuel technology. It’s your quick guide to information to help you comply with regulations, save money and hit your decarbonisation targets. All the alternative fuels knowledge you need in one place.


A – Ammonia

Ammonia, a compound of nitrogen and hydrogen, is produced by bacteria in soil and through the decomposition of organic matter. A common sight across a variety of industries, ammonia as a fuel emits no CO2 when combusted and can be carbon free when it’s made using renewable energy. Though precautions must be taken when storing and handling it onboard ships, engines that use ammonia for fuel are at a very advanced stage of development.

Get answers to your top questions about this promising future marine fuel in Ammonia as marine fuel? It is easier if you do it smart. The article  explores the many sides of using ammonia as a marine fuel and provides insights on how to do it smart.


B – Biofuels 

Produced from renewable biomass like vegetable oils, animal waste and crop residues, marine biofuels come in both liquid and gaseous forms, and offer an interesting alternative to fossil fuels for the maritime industry.

What is biofuel, where does it come from, how is it made and what do you need to think about before starting to use it? Find out by reading No more mysteries about marine biofuels – your top six questions answered.


C – Conversion

Fuel conversion refers to the process of adapting vessel engines and their associated fuel storage and supply systems to use a fuel other than the one they were originally designed for. With CII now in force, conversion is one way to avoid stranded assets and gain the flexibility to adopt future fuels quickly and easily. 

Handpicked related content: Make your marine fuel conversion a success – 5 important things to consider

Fuel conversions for ship engines offer immediate benefits in terms of carbon, SOx and NOx reductions.

Did you know that vessels powered by 2-stroke engines account for 80% of the global maritime fleet’s total emissions? Help is at hand in the form of The Wärtsilä 2-Stroke Future Fuels Conversion Platform – A fuel-proof way to gear up for decarbonisation. With this platform you can ensure regulatory compliance and get your vessel ready for fuel blends and eventually future fuels such as green ammonia and green hydrogen.


D – Decarbonisation

In maritime decarbonisation the biggest challenge and opportunity is fuel – the future sustainable fuels to power global shipping and the global actions that need to be taken to scale their production and infrastructure. Sustainable maritime fuel is one of the topics covered in the blockbuster eBook: 50 great ways the maritime industry could reduce its greenhouse gas emissions. The eBook is your go-to guide when looking for inspiration on how to cut the greenhouse gas emissions of your vessels.

A great first step to determining where you stand from the perspective of CII is to download the white paper: Discover the real CII status of your vessels – and how to improve it. And if it turns out that you own a vessel that is, or soon will be, in CII category C, D or E, Decarbonisation Services from Wärtsilä can help you find the optimal pathway to decarbonise your operations.

To kick-start your thinking about what might be the right decarbonisation solutions for your operational profile and business case, check out these 3 simple steps to a low-carb vessel diet. The good news is that Wärtsilä Decarbonisation Services can help with them all.


E – Environment

Are future fuels better for the environment? All future marine fuels – LNG, ammonia, biofuels, methanol and hydrogen, to name the main contenders – reduce carbon emissions from shipping. How environmentally friendly they are depends on how they are produced. A lifecycle approach to ship-generated emissions takes the entire value chain of the energy source “from well to wake” into account. This includes the energy related to production and logistics of the fuel in addition to the emissions created by combustion onboard.

Colours are used to denote the sustainability of different production routes. For example:

  • Hydrogen can be grey, blue, green or even pink
  • Ammonia can be grey, blue or green
  • Methanol can be green, grey, brown or blue

Take a look at the dictionary of future fuels to learn more.


F – Future fuels development

New future fuels in shipping are being developed all the time. They include bio and synthetic liquefied natural gas (LNG) as well as ammonia, methanol, hydrogen and biofuels. There is also a wide range of engine and fuel gas supply systems under development to help you navigate the route to reduced greenhouse gas emissions – whatever fuel you choose.

You’ll find a comprehensive overview of the current state of future fuels in the marine industry and the three key elements to success in this wide-ranging, research-backed report: Sustainable fuels for shipping by 2050 – the 3 key elements of success. The report reveals the key actions that need to be taken now to make sustainable shipping a reality by 2050.


G – Green corridors

Green shipping corridors link ports that support zero-emission fuels and they are showing great potential as a way to accelerate maritime decarbonisation. They are routes where the economic, logistical and political conditions are favourable to zero-emission shipping.

Five important facts you might not know about green shipping corridors explains how these routes are a key solution to securing clean fuel for your vessels.


H – Hydrogen as a marine fuel

Hydrogen, the simplest element, sits at the beginning of the periodic table and is commonly utilised in its gaseous form H2. It has sent crews and cargo into space and today is used to power cars and other land-based vehicles. But could hydrogen be the fuel for the future of shipping? Liquefied hydrogen has already been transported by ship, but not used as a fuel onboard. What are its pros and cons, and what is the status of marine hydrogen engine technology?

If you’re curious about the current state of play and future outlook, Hydrogen – Fuel for thought in our Q&A has everything you need to know.

New future fuels in shipping are being developed all the time. They include bio and synthetic liquefied natural gas (LNG) as well as ammonia, methanol, hydrogen and biofuels.


K – Knowledge

Find alternative fuels knowledge here:

L – LNG 

Liquefied natural gas (LNG) is natural gas that has been cooled down to -162ºC (-260ºF). Cooling the gas reduces its volume significantly, making it easier and safer to transport and store. Today LNG is a well-established maritime fuel that has been adopted across a variety of vessel segments. No surprise given that it can help you reduce greenhouse gas emissions significantly and provides an excellent platform for other future fuel options too. Why is it such an attractive prospect, and how is the critical issue of methane slip being addressed?

For answers, look no further than LNG – Fuel for thought in our deep-dive Q&A, which will help you to weigh up what LNG has to offer and what you need to take into account when considering it as an option.

One of the challenges with LNG is methane slip – the small amount of the fuel that doesn’t burn in the engine and escapes with the exhaust gases instead. How to be smarter about methane slip – right now will help you discover simple solutions that can bring results quickly. 

Handpicked related content: How to reduce methane slip – winning tactics for your maritime business


M – Methanol as marine fuel

Methanol is the simplest alcohol and a chemical building block for everything from plastics and paints to building materials. So what makes this biodegradable alcohol one of the top alternative fuels that vessels could use in future? And how might its role as a fuel of the future develop?

Head on over to Methanol as marine fuel – is it the solution you are looking for? to learn the answers to these questions – and many more.

The white paper 4 clear examples – proof that methanol could really work for your vessel reveals four real-life examples of how operators are already using methanol to solve their challenges, and how you can start using it to reduce emissions immediately.


N – NOx

NOx is short for the nitrogen oxides N2O, NO, N2O3, NO2 and NO3. These are chemical compounds of oxygen and nitrogen that are formed when fuel and organic matter are combusted at high temperature. You can find out more about NOx and their harmful effects from the NOx Fund website.

Some interesting facts on NOx and future fuels:


P – Poseidon Principles

The Poseidon Principles is an initiative that aims to establish a framework for assessing and sharing the carbon footprint of ship finance portfolios. There are currently around 30 leading banks signed up, with many more expected to follow. If you’re looking to invest in new shipping assets, getting the finance to build them could be easier if they’re designed to be more environmentally friendly.

Maritime regulations and opportunities in 2023 – your keys to success tells you why fortune favours the brave when it comes to decarbonisation. 


Q – Quick guides to future fuels

Get all the facts you need about future fuels from these handy one-page quick guides:


R – Renewable

Which future fuels are renewable?

Renewable fuels are produced from renewable resources. For example, biofuels produced from vegetable oil, methanol produced using clean energy, hydrogen produced using renewable processes and synthetic fuels (electrofuels, or eFuels for short) produced from captured carbon dioxide and water. Wikipedia has a useful roundup on the subject.


S – Synthetic fuels (eFuels)

eFuels are part of a wide range of new future fuels in shipping that are being developed all the time. You can learn more about them on the eFuel Alliance website.


V – Volumetric energy density

When you’re weighing up your future fuel options, volumetric energy density is an important consideration. It’s defined as the amount of energy contained in a fuel per unit volume.

Essentially, the lower the volumetric energy density, the more volume of fuel you’re going to need to store and use onboard to do the same amount of work. Ammonia, for example, has a lower volumetric energy density than LNG


W – Wärtsilä methanol engines

Are you considering methanol as a future fuel for your new or existing vessels? An engine that’s been built from the ground up to run on methanol is a sure-fire way to get the most from this increasingly popular option on the future transport fuels menu. Learn how methanol engines give you the power to achieve carbon neutrality.

You can also watch the webinar Wärtsilä 32 methanol – The power to reach carbon-neutral for an overview of methanol as a maritime fuel and a deep dive into the nuts and bolts of the new engine. 



The Zero Emission Energy Distribution at Sea (ZEEDS) initiative is leading the way towards a cleaner and more sustainable future for the shipping industry. The initiative includes companies such as Wärtsilä, Aker Solutions, DFDS, Grieg Star and Kvaerner.

The ZEEDS partners imagine that the infrastructure of the future is composed of fuel hubs where wind turbines would be used to produce hydrogen from water, and ammonia would be made from hydrogen and nitrogen extracted from the air. The ZEEDS concept was initially modelled for the North Sea and Baltics, where some of the busiest shipping corridors are located and where the development of renewables is already highly advanced.

Learn how Wärtsilä is Building sustainable shipping with ZEEDS.

What are the essential elements to success in making sustainable fuels for shipping a reality by 2050?
Get all the inside knowledge you need, including a clear sustainable fuels roadmap to 2050, in the report: Sustainable fuels for shipping by 2050 – the 3 key elements of success.

Written by
Charlie Bass

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