The next five years will be transformative for ammonia and will see a new story written with shipping at its heart.
In 2025, we will see the first working engines burning ammonia as marine fuel, and global ammonia production will significantly grow, from 240m tonnes in 2023 to 290m tonnes by 2030.
Counterintuitively, these two developments are not necessarily connected. The real story behind ammonia’s explosive growth forecast is its pivotal role in the emerging hydrogen value chain.
For shipping, the energy transition is about the confluence of two stories: shipping for shipping and shipping for the world.
“Shipping for shipping” refers to the industry’s own decarbonisation efforts, while “shipping for the world” highlights its crucial role in enabling the global green energy transition — particularly as a transporter of future fuels, including those in the emerging blue and hydrogen value chains.
Such is the expected demand for hydrogen’s carbon-free power that global production is anticipated to soar as high as 500m tonnes by 2050. But there is a hitch in this hydrogen hegemony theory.
H2 is a particularly challenging product to safely transport at scale. This is due to a combination of factors but principally because it has the lowest density of all gases and is also highly flammable.
Less well-known is that hydrogen atoms can permeate solid metals due to their small size.
Known as hydrogen embrittlement, the metal becomes susceptible to cracking due to the absorption of hydrogen atoms into its crystal lattice, significantly reducing its tensile strength and ductility, and potentially leading to failure under stress.
This is particularly challenging when you consider hydrogen needs to be compressed to 11,603 pounds per square inch, compared with LNG at 3.6 psi.
Liquefaction presents its own issues, with hydrogen needing to be kept at -253C compared to -160C for LNG.
All of this is ultimately just another technical challenge, and our industry has proven it can master those time and time again.
Except this time maybe we don’t need to, because there is another option: ammonia, or NH3.
Even though you typically lose 15% to 25% of the energy contained in ammonia when converting it to hydrogen through a process called “cracking” — meaning only 75% to 85% of the energy is effectively converted to hydrogen — ammonia is considered a promising hydrogen carrier because it has a higher energy density than pure hydrogen and can be more easily transported and stored as a liquid.
Ammonia’s liquefaction process requires just 11% of its energy content, far less than the 30% to 36% needed to liquefy hydrogen to cryogenic temperatures.
Additionally, ammonia’s low boil-off losses make it well-suited for transport, in contrast to liquid hydrogen’s 0.3% per day boil-off rate, which creates further operational challenges and energy losses. Hydrogen can be released on demand from ammonia, through catalytic decomposition, and consumed in a fuel cell.
Crucially, ammonia leverages a globally established network of more than 120 ammonia-capable ports, along with pipelines, tankers and storage facilities developed over decades for industrial applications like fertilisers, ammonia’s principal application globally today.
This infrastructure significantly reduces the need for capital investments to scale up. Liquid hydrogen, by contrast, faces steep barriers due to the absence of cryogenic transport and storage systems, requiring substantial investments in new tankers, insulated pipelines and specialised port facilities.
In fact, the transport cost for ammonia of $0.40 to $0.50 per kg of hydrogen over 5,000 km is far lower than liquid hydrogen’s $1 to $1.20 per kg due to these factors.
When you consider the boundary conditions that constrain the development of any fuel — safety, availability, scalability and, finally, affordability — ammonia is ahead in every measure.
So, wherever hydrogen is needed, ammonia is often the simplest, safest and cheapest way to get it there. And shipping has been transporting ammonia safely for decades.
Ammonia today is a wild-card market, with growth subject to a range of technical and geopolitical pressures. But while there may be disagreement on the degree of growth, the overall direction is clear.
As the world turns to electrification to decarbonise operations, hydrogen will frequently be the answer. And ammonia will be the transport vector for much of it.
In the meantime, there is work for shipping to do to ensure it can play a full part in tomorrow’s global economy.
There is an estimated shortfall of between 100 and 180 vessels by 2035, and these will need to be vastly bigger than those on order today, with typical sizes likely to follow LNG carriers above 150,000 cbm and ultimately, even to 200,000 cbm.
The ammonia story is just getting started, with significant growth likely from 2030 onwards. It is already clear that shipping will move from a minor player today to a leading force in the future.
Christopher Wiernicki is chief executive of classification society American Bureau of Shipping.
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