Shipping giant Maersk has placed an order for up to ten “very large ammonia carriers” from South Korea’s Hyundai Samho Heavy Industries, in order to ship NH3 produced from clean hydrogen across oceans.

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At 93,000 cubic metres of cargo space, these ships will be the joint largest ocean-going ammonia carriers in operation on delivery in late 2026.

“Concrete actions are needed for the tanker industry to progress the energy transition, and in Maersk Tankers, we want to play our part in making transportation of clean energy a reality,” said Tina Revsbech, CEO of Maersk Tankers.

“We are building on our legacy of operating gas carriers to offer a crucial transportation service that will aid the transition. With this initiative, we will be able to service clean ammonia producers and users in many parts of the world with highly energy efficient and safe ships,” she added.

While Maersk and Japanese conglomerate Mitsui have jointly invested in four vessels, the contract also includes the option to increase the order by another six carriers.

A number of other companies have this year also placed orders for ammonia carriers of the same size, many of which are set to be delivered in the late 2020s.

Greek shipping firm Naftomar last month confirmed its order for four 93,000 cubic-metre carriers from South Korean shipbuilder Hanwha Ocean, which are also due for delivery in 2026.

Meanwhile, in May Singapore-based Eastern Pacific Shipping in May also placed an order for four 93,000 cubic-metre “very large gas carriers”, capable of storing liquefied petroleum gases or ammonia, with Chinese shipbuilder Jiangnan, which some reports have suggested could be due to a lack of capacity at Korean shipyards.

While purpose-built ammonia carriers already exist today, their combined capacity is nowhere near enough to meet future demand, and most of these vessels are fairly small and not designed for ocean-going shipments.

According to data from shipping analytics firm Vortexa, only 114 unique vessels had loaded ammonia with a combined liquid capacity of around 3.12 million cubic metres (capable of carrying around 1.9 million tonnes of NH3) between mid-2021 and mid-2023.

For comparison, the Neom green hydrogen and ammonia complex in Saudi Arabia — the largest such project to start construction — is due to start producing 1.2 million tonnes of NH3 a year in 2026.

Ammonia as a fuel

Maersk is also working with Hyundai Heavy Industries’ engine machine division and German engine manufacturer MAN Energy Solutions to make the vessels capable of running on NH3.

But the shipping firm notes in a press release that “a decision to install ammonia capable engines requires both regulatory and customer support”.

This likely refers to the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), which currently prohibits the use of toxic products — including ammonia — as a fuel for these carriers.

However, the International Maritime Organization is currently drafting new guidelines for the use of NH3 as a fuel, which are scheduled to be approved in December 2024.

Maersk also has 25 vessels capable of running on methanol on order, with its first — the Laura Maersk — already in operation.

The shipping giant currently sources its methanol from biogenic sources due to a lack of available green H2 feedstock. However, its subsidiary C2X is in the midst of developing a facility in Egypt able to produce up to 300,000 tonnes of renewable hydrogen-derived methanol per year from 2027 or 2028.