Hoping to spearhead the development of a global market, high-profile deals such as the Japan-Australia Hydrogen Energy Supply Chain (HESC) project in Victoria plan to use ships to transport liquid hydrogen across continents.
Led by an industry consortium, the HESC project aims to produce 40,000 tonnes of hydrogen from brown coal per annum by 2030 for export to Japan. Australian state and federal governments have already each contributed $50 million to the $500 million project, which is now awaiting approval of the commercialisation stage following the completion of the pilot in early 2022.
The HESC project is one of many on a long list of hydrogen export announcements around the world that are struggling to get off the ground.
Despite the enthusiasm, no hydrogen trade industry exists anywhere in the world in 2024. Import deals lag far behind the scale of planned exports, and globally, almost all hydrogen continues to be produced and used in the same place.
This isn’t because transporting hydrogen is impossible. It’s because faced with the challenges of moving hydrogen long distances, there is almost always a better energy transition solution.
Why is this the case, and what does this mean for initiatives like the HESC project? Let’s look at the facts.
Shipping pure hydrogen
Pure hydrogen is extremely challenging to transport via ship. Taking up so much space at normal temperatures due to its extremely low energy density, the only way to move it long distances is to compress or liquefy it.
Shipping hydrogen as a compressed gas in large quantities is a non-starter. At the immense pressure of 150 bar, 15 ships of compressed hydrogen would be needed to carry the same amount of energy as one typical liquid natural gas (LNG) tanker.
Shipping liquefied hydrogen is almost as impractical, and rife with technical difficulties. It has been attempted in the real world just once to date as part of the HESC pilot project, resulting in a brief fire onboard the carrier ship.
One of the greatest technical challenges here is that hydrogen becomes a liquid at atmospheric pressure at minus 253 degrees Celsius – just above absolute zero, the lowest temperature possible.
Even at this temperature, it is still not very dense: fitting about 71 kilograms of hydrogen per cubic metre, and requiring 2.4 times the number of cargo ships to carry the same amount of energy in the form of liquefied hydrogen versus LNG.
A cycle of losses
Liquefying hydrogen is also a highly energy-intensive process that outright consumes about a third of its energy. More hydrogen will be lost daily during transport as some of it boils – known as boil-off – as keeping heat out of a liquid that boils at -253 C is a major challenge.
Recapture and re-condensation of this boil-off is not possible during transit, presenting a climate problem as hydrogen has a global warming potential 35 times that of carbon dioxide (CO2) in the first 20 years after its release into the atmosphere.
Hydrogen is a small molecule, and is far more prone to leak from pipes and storage tanks than natural gas – risking releasing significant fugitive emissions during transport as a result.
If electricity is used to make renewable hydrogen, which is then liquefied, shipped overseas and used to make electricity at its end destination, less than one third of its original energy input will remain by the end in a best-case scenario.
In the case of hydrogen made from coal, like in the HESC project, the energy loss is 80% even before energy for carbon capture and storage (CCS) is considered.
This means shipping liquefied hydrogen will deliver an energy loss of between 70-80% – without even accounting for boil-off or the energy used to power the ship for its transport.
Other export options – such as hydrogen-derived ammonia or methanol – face similar challenges. If renewable ammonia or methanol is made from hydrogen, shipped across the ocean and converted back into hydrogen for use at an end destination, at least 75% of the original energy input will be lost.
Alternative solutions
Ultimately, will the HESC project overcome the significant hurdles facing hydrogen exports? The facts aren’t painting an optimistic picture.
Shipping hydrogen long distances is technically possible but difficult to make viable from a practical, economic and energy efficiency standpoint. It should only be used as a last resort.
Rather than betting on technically challenged initiatives like the HESC project, Australia should take advantage of its vast renewable energy resources in places like Western Australia to economically produce renewable hydrogen at scale.
It could use this renewable hydrogen to become a production hub for green, energy-intensive materials and chemicals that are currently made from fossil fuels such as ammonia for use as fertiliser, methanol for use as a chemical feedstock, and iron for steel-making.
These products produced locally using renewable hydrogen as a raw material, and then exported – such as steel – are much a better option than navigating the difficulties of exporting hydrogen itself.
By refocusing investment in production hubs for hydrogen-made products, Australia would be placing a stronger bet on future clean industries rather than wasting time on the HESC project which is scientifically destined to fail.
Paul Martin is a chemical engineer and co-founder of the Hydrogen Science Coalition.
