By the end of the decade, it is likely to be cheaper to ship hydrogen across long distances in the form of ammonia or liquid organic hydrogen carrier (LOHC) — and then convert it back to H2 at its destination — rather than transporting it as liquefied H2, according to a new report from the International Energy Agency (IEA).
Transporting compressed hydrogen via repurposed long-distance gas pipeline — or a new large-diameter pipe — would probably be even cheaper, where feasible, according to the 459-page Energy Technology Perspectives 2023 study, which was published yesterday (Thursday).
“In 2030, LH2 [liquid hydrogen] tanker technology is expected to reach the early commercialisation phase, with transport costs of delivering hydrogen averaging $2.0-3.7/kgH2 for an 8 000-km trip in the NZE Scenario,” says the report.
“The costs of shipping ammonia and LOHC are expected to be lower, at $1.9-2.2/kgH2 and $2.0-2.5/kgH2 respectively.”
These figures include investment and operational costs, including converting hydrogen to a higher-density carrier, storing it, shipping it and converting it back to gaseous H2 — but not the costs of producing hydrogen.
The above chart, taken from the document, shows that the shipping part of the transportation process will only make up a small fraction of delivery costs, with the conversion of gaseous hydrogen to more energy-dense carriers (ie, LH2, ammonia or an LOHC called methylcyclohexane (MCH)) and back to gaseous H2 — along with energy losses from the two conversion processes — responsible for the vast majority of the costs.
In the case of LH2, the highest cost element will be the storage tanks at both the export and import ports — a result of its relatively low energy density by volume and need to be kept at temperatures below minus 253°C.
Liquid ammonia can store 121kg of hydrogen per cubic metre, compared to MCH's 47.3kg/m3 and 71kg/m3 for LH2.
The forecasts will come as a blow to the international Hydrogen Energy Supply Chain project, which has invested $350m to ship LH2 from Australia to Japan, including the construction and operation of the first LH2 carrier, the Suiso Frontier.
As about 43% of all hydrogen used worldwide is to produce ammonia, it is not expected that much, if any, imported ammonia would be cracked back into gaseous H2 — unlike LOHC.
Removing the cost of converting this NH3 back to hydrogen, and ammonia can be shipped up to 8,000km for about $1 or less per kg of hydrogen content.
This is why ammonia is usually seen as the most favourable method of shipping hydrogen between countries. NH3 can also be used as a maritime fuel, unlike LOHC, with many ammonia-powered vessels being planned around the world.
However, all these shipping costs are still far higher than transporting natural gas by vessel, the report points out.
“Overall, the cost of shipping hydrogen as LH2, ammonia or LOHC is $16-31/GJ [gigajoule] by 2030 in the NZE Scenario. This is considerably more than the average cost range of liquefaction, shipping and regasification of natural gas, which is currently around $3-7/GJ.
“However, if hydrogen can be produced at low cost, despite high shipping costs, its cost could be lower than recent record high international gas prices.”
Pipelines
However, the IEA points out that long-distance pipelines would be a lower-cost and therefore preferable option to shipping hydrogen for cross-border trade.
“It is likely that, where feasible, onshore or offshore pipelines will be preferred: it is the most efficient and least costly way to transport hydrogen up to a distance of 2,000-2,500 km for capacities below 600 ktpa (kilotonnes per year) in 2030 in the NZE [Net Zero Emissions by 2050] Scenario,” says the report.
It adds that large-diameter pipelines of 48 inches (122cm) wide “may be cheaper even over longer distances, where feasible”, while pointing out that hydrogen production “may be too small initially to justify investment in a large pipeline (with significant oversizing until production grows), or the construction of a pipeline across different jurisdictions may be impracticable”.
A repurposed 48-inch pipeline would be able to deliver hydrogen up to 6,000km for less than $0.50/kgH2, a chart in the document suggests, with a new pipe of the same diameter costing about double that — still way cheaper than any of the shipping methods.
Another option — to transport electricity via long-distance offshore high-voltage direct-current and then use it to produce hydrogen via an electrolyser —would be highly likely to be the most expensive option, the report suggests. And, of course, long-distance offshore cables are far cheaper (and easier) to lay than long-distance onshore transmission lines strung from hundreds of pylons stretching across the countryside.
