The International Energy Agency (IEA) has predicted that ammonia and hydrogen will come increasingly to the fore over the coming decades and oil and gas will be responsible for only one-sixth of total shipping fuel consumption in 2070.
In its newly-published Energy Technology Perspectives 2020, the IEA said that the maritime shipping sector is ‘at a crossroads’ as it looks to meet the ‘real challenge’ posed by the growing number of regulations requiring ships to reduce their GHG and air pollutant emissions with energy-efficient technologies and low-carbon alternative fuels.
The IEA report set out the extent of the challenge: ‘Shipping by its nature mostly involves large vessels travelling long distances, and existing alternatives to oil-based fuels are either impractical or very costly. Moreover ships have a long lifetime of 20-35 years, which inhibits the uptake of new low-carbon technologies.’
The report said that: ‘Reducing emissions from large transoceanic ships will be particularly onerous, requiring large investments and co-ordinated efforts among fuel suppliers, ports, shipbuilders and shippers, (especially so-called tramp shipping).’
The report then summarised the decarbonisation options open to the shipping industry.
‘In the short term,’ according to the IEA, ‘there is considerable potential for curbing fuel consumption with energy efficiency, measures to optimise supply chains and slow steaming. In the medium to longer term, significant emissions reductions could be achieved by switching to low-carbon fuels such as biofuels and emissions-free hydrogen-based fuels (ammonia and hydrogen), which look likely to be particularly important for long-range transoceanic travel. Larger ships that carry freight over long distances need fuels with high energy density. Coastal short-distance ships can use less energy-dense fuels, making a switch to battery electric power technically feasible.’
The report predicted that alternative fuels will play an increasingly important role in the bunker market over the coming decades – with ammonia emerging as the predominate marine fuel.
In the short term, the report noted, shipping will be mainly using very low sulphur fuel oil (VLSFO) and distillate fuels, with some shipping operations opting to use LNG.
In the medium term, blending with biofuels will increase as ‘biofuel use jumps from negligible levels today to more than 25 Mtoe in 2040 and to almost 50 Mtoe in 2060, by which time it accounts for more than one-fifth of total energy use in shipping’. However, the IEA noted that the supply of biofuels for all transport sectors is constrained by the availability of sustainable biomass.
In the longer term, biomass-to-liquids (BTL) will become more important as BTL moves to large-scale production from about 2050, and ammonia and hydrogen will ‘come increasingly to the fore’.
The IEA report predicted that ammonia and hydrogen will together be used on over 60% of new vessels sold after 2060 – and ammonia use for shipping will reach ‘roughly 130 Mtoe in 2070, almost twice as much as was used worldwide for fertiliser production in 2019’.
The role of hydrogen as a fuel for large vessels will be more limited, due to the high costs of hydrogen storage and its lower energy density.
‘Nonetheless,’ said the IEA, ‘hydrogen use reaches 12 Mt in 2070, equivalent to 16% of 2019 global maritime bunker demand and 16% of today’s global hydrogen use. By this time, oil and gas are responsible for only one-sixth of total shipping fuel consumption.’
Click here to download the IEA’s Energy Technology Perspectives 2020.