Ammonia and hydrogen are considered as the main marine fuels, in case the world reaches net-zero in 2050, thus accounting for around 60% of the market, while ammonia will occupy the largest share, said the International Energy Agency (IEA).
As IEA says in its Roadmap for the Global Energy Sector, maritime shipping was responsible for around 830 Mt CO2 emissions worldwide in 2020, which is around 2.5% of total energy sector emissions.
Due to a lack of available low‐carbon options on the market and the long lifetime of vessels (typically 25‐35 years), shipping is one of the few transport modes that does not achieve zero emissions by 2050 in the NZE. Nevertheless, emissions from shipping decline by 6% annually to 120 Mt CO2 in 2050
What is more, in the short term, there is considerable potential for curbing fuel consumption in shipping through measures to improve operational efficiency and energy efficiency. Such approaches include slow steaming and the use of wind‐assistance technologies.
In the medium to long term, significant emissions reductions are achieved in the Net Zero Emissions (NZE) by switching to low‐carbon fuels such as biofuels, hydrogen and ammonia.
Ammonia looks likely to be a particularly good candidate for scaling up, and a critical fuel for long‐range transoceanic journeys that need fuel with high energy density
Ammonia and hydrogen are now the main low‐carbon fuels for shipping adopted over the next three decades in the NZE, their combined share of total energy consumption in shipping reaching around 60% in 2050. In fact, the 20 largest ports in the world account for more than half of global cargo. These ports could become industrial hubs to produce hydrogen andammonia for use in both chemical and refining industries, as well as for refuelling ships.
As for internal combustion engines for ammonia‐fuelled vessels, these are currently being developed by two of the largest manufacturers of maritime engines and are expected to become available on the market by 2024.
Sustainable biofuels provide almost 20% of total shipping energy needs in 2050. Electricity plays a very minor role, as the relatively low energy density of batteries compared with liquid fuels makes it suitable only for shipping routes of up to 200 km
Even with an 85% increase in battery energy density in the NZE as solid state batteries come to market, only short‐distance shipping routes can be electrified.