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What do we mean by new fuels?

24 April 2024

There are numerous options in the mix to replace heavy fuel oil and diesel, and opinion is divided on which of these new fuels – also known as 'future fuels' or 'alternative fuels' – will end up on top. Lucy Chapman explores the pros and cons of some of the main contenders


Does not release greenhouse gases when burnt as fuel - only water vapour and oxygen Highly explosive if not stored and handled correctly
Already a global hydrogen market Combustion can lead to the thermal formation of nitrogen oxides (NOx)
Can be stored in large amounts for long periods of time Low energy density increases storage needs
Only releases water vapour and oxygen as by-products. Easy to fit existing ships with hydrogen fuel cells Producing hydrogen from renewable sources is expensive


Does not release greenhouse gases when burnt as fuel Most ammonia is produced from natural gas - a fossil fuel
Green ammonia causes no greenhouse gases when burnt as fuel Highly toxic - even small volumes in the air can be fatal
Easy to store and transport Combustion can produce NOx emissions
Low flammability Highly corrosive

Methanol biofuel

Low NOx, sulphur oxide (SOx) and particulate emissions Releases some greenhouse gas emissions when burnt as fuel
High energy density requiring less storage space Most methanol is produced from natural gas, a fossil fuel
Compatible with most engine types Lower energy density than traditional marine fuels
Liquid, easier to handle Can be corrosive and toxic

Wind propulsion

Beneficial for long crossings Noise pollution
Can be combined with other renewable sources Wind conditions can be variable and unpredictable
Zero emissions Fitting vessels with wind propulsion systems can require significant investment upfront
Sustainable Occupies a lot of space

Shore-charged batteries

Zero emissions (if electricity for charging is produced through green technology) Still not efficient - cannot store enough energy for their size and weight
Practical for vessels that dock often Emissions from charging power produced using fossil fuels
Can be charged using electricity from renewable sources Requires collaboration between ports, shipping companies and utility providers
Reduced noise pollution Impractical for vessels that do not dock often

Liquefied petroleum gas (LPG)

Easy storage Not carbon free
Produces less SOx, NOx and CO2 than traditional marine fuels Flammable and potentially hazardous
Widely available globally Fluctuating prices
Efficient and reliable Lower energy density than traditional marine fuels

Liquefied natural gas (LNG)

Reduces NOx emissions by up to 80% and virtually eliminates SOx particles compared with traditional marine fuels Still a fossil fuel that emits CO2 and sometimes unburnt methane during combustion
Non-toxic and non-corrosive Lower energy density than traditional marine fuels
LNG spills cause little marine environmental damage unless ignited before evaporation can occur Converts to flammable gas when in contact with air
Widely available globally Stored at a very low temperature and complex to handle




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