Why power a short-distance Ferry with Liquefied Hydrogen?

The global shipping industry is a significant contributor to climate change. In recent years, there has been considerable interest in alternative shipping fuels derived from green hydrogen — like methanol or ammonia. But what about hydrogen itself? Is green hydrogen a suitable shipping fuel? And if so, what could its role be in a future climate-neutral shipping industry?

The shipping industry is, of course, operating under very diverse circumstances. Small passenger ships operating over short distances will require different solutions than container ships crossing oceans with distances of several thousand kilometers.

For passenger transport on short distances, battery-electric ferries are already providing a solution that allows powering ships with renewable electricity. Battery-electric ferries also have the benefit of avoiding air pollution, often in populated areas.

The largest battery-electric ferry, the Bastø Electric, can transport up to 600 passengers and covers a distance of about 10 kilometers near Oslo in Norway. The record for the longest distance ever covered by a battery-electric ship is held by the Danish ferry Ellen, which traveled 92 kilometers on a single battery charge in 2022.

Yet, batteries have limits. Due to their low energy density per weight, they are too heavy for larger ships and longer distances. And while future technology will certainly increase the range and size of battery-powered vessels, it appears unlikely that large container ships powered by batteries will cross oceans.

Alternative fuels like methanol and ammonia could provide the energy density needed. Today, both chemicals are almost entirely made from fossil fuels. However, they could be derived from green hydrogen and indirectly power ships with renewable energy.

Methanol has the advantage that it is similar to existing fuels and thus easier to implement, but it needs a sustainable carbon source. Ammonia, on the other hand, contains no carbon, but the technology is more experimental. Ammonia is difficult to ignite, its combustion can cause NOx and N₂O emissions, and ammonia is a highly toxic gas and, therefore, an enormous safety risk. Yet, discussing the pros and cons of ammonia and methanol is a topic for another time.

Where does hydrogen itself fit into the picture? Hydrogen has a high energy density per weight — higher than any other fuel. But it has a very low energy density per volume.

To use hydrogen as a fuel, it can either be compressed or liquefied. But even in its most dense, liquefied form, hydrogen contains less energy per volume than ammonia, methanol, or other fuels.

If anything, Hydrogen could serve the mid-sized Shipping Market

Due to its properties, if hydrogen is used as a shipping fuel, it would most likely be used in the mid-sized shipping segment. Ships with sizes and ranges too large to be powered by batteries, but also not the largest ships, which will be better served by energy carriers with a higher volumetric energy density.

It is possible that the direct use of hydrogen fuel will not play any major role in shipping, as it comes under pressure from two sides. Improved batteries will increasingly cover the small-to-medium-sized shipping segments, and once fuelling infrastructure for fuels like methanol is available for the largest ships, there may not be much room in between.

Danish shipping company DFDS has at least looked into hydrogen-powered options for its ships. In 2020, DFDS announced plans to convert a ferry between Copenhagen in Denmark and Oslo in Norway — around 500 kilometers distance — to hydrogen. However, the project was shelved after DFDS failed to get support from an EU funding program.

DFDS does not appear particularly eager to continue exploring hydrogen as a fuel. In a 2024 press release, the company writes: "DFDS has recently launched its 'Vessels of tomorrow' program, which will see two methanol, two electric, and two ammonia vessels added to the company's fleet over the next six years."

Notably, hydrogen is not on that list, but DFDS performed a feasibility study for the conversion of another ship — the Magnolia Seaways — operating between Esbjerg in Denmark and Immingham in the UK (around 600 kilometers).

While it is unclear whether any of these projects will ever be realized, they are within the medium-distance range and size where hydrogen could play a role if it is going to be used at all.

A dutch company named AMS Barging operates two container ships with compressed hydrogen, the H2 Barge 1 and 2, which connect ports in the Netherlands, Belgium, and Germany. Given these routes are either on rivers or close to the coastline, one may wonder whether battery-swapping technology could also be used. Still, it does not seem entirely unreasonable to test hydrogen-powered solution on such routes.

Compressed hydrogen is also what Norwegian ferry company Torgatten Nord wants to use for two new ferries currently being built. Torgatten Nord plans to use the hydrogen-powered ferries on a route connecting Norway's mainland with the Lofoten islands (around 90 kilometers).

Compressed hydrogen still has a relatively low energy density per volume. In other words: it needs a lot of space for its storage tanks. An alternative to achieve volumetric energy densities that come at least close to other fuels is liquefied hydrogen, or LH₂. To liquefy hydrogen, it needs to be cooled down to very low temperatures (-253°C / -423°F). That comes with considerable additional challenges.

In its feasibility study for the Magnolia Seaways, DFDS writes: "While liquefied hydrogen offers the highest energy density, both volumetrically and gravimetrically, its storage is always connected with significant losses due to boil-off effects for longer-term storage. Also, liquefaction is very energy intensive and the necessary infrastructure for bunkering and logistics is much more complex than for gaseous storage. Furthermore, due to the very low temperatures, the liquefication plant cannot adapt to capacity changes quickly. For example, the start-up of such a plant takes about one week to reach stable operation, as opposed to a couple of minutes for a compressor. The low temperature adds some additional risks for spillage, such as thermal stress fractures of materials."

From Boil-Off Gas to Greenhouse Gas

The mentioned boil-off effect deserves more explanation. If a gas is cooled and liquefied, unavoidably, some of it will regasify due to temperature exchange with its environment. DFDS mentions that this causes significant losses, but that is not the only problem.

Hydrogen fuel is often pitched with the claim that its use as an energy source only emits water vapor. However, hydrogen gas itself can also be emitted, and hydrogen is an indirect greenhouse gas.

To be climate-friendly, hydrogen-powered ships need to avoid any significant hydrogen emissions. Yet, with liquefied hydrogen and its unavoidable production of boil-off gas, this becomes challenging. Boil-off gas can be used to power the ship while it is operating, but the boil-off effect does not stop while the ship is docked in a port. Any resulting hydrogen gas that is not directly used, reliquefied, or burned off will contribute to climate change.

Boil-off gas is also produced during transport of liquefied hydrogen and in storage systems. A publication from researchers at Columbia University about hydrogen emissions notes that emissions due to boil-off may be particularly problematic for hydrogen truck delivery to small refuelling stations: "Compared with pipeline systems, this method is both less important in terms of scale and leakier, mostly due to boil-off losses."

It is probably fair to say that liquefied hydrogen comes with many challenges. If done the wrong way, LH₂ could actually cause more problems than it solves.

MF Hydra, the world's first Ferry running on LH₂

Norled is a passenger ferry operator in Norway. Since 2023, Norled has operated the MF Hydra, the world's first ship powered by liquefied hydrogen, to transport passengers across the Jøsenfjorden near Stavanger.

When the MF Hydra entered operations, the Norwegian Public Roads Administration (NPRA, Statens Vegvesen) wrote: "MF Hydra sails on zero-emission liquid hydrogen."

To source its zero-emission liquid hydrogen, Norled entered an agreement with Linde, a chemical company headquartered in Germany. In March 2021, Linde wrote in a press release: "Liquid hydrogen will be supplied from Linde's new 24MW electrolyzer at the Leuna Chemical Complex in Germany, which will use PEM (Proton Exchange Membrane) technology to produce green hydrogen. Linde will also build and install onshore and onboard hydrogen storage, distribution, and safety equipment."

The idea that a ferry operator in Norway would source green hydrogen from a plant in Germany might appear puzzling. If anything, one would expect the opposite.

In Germany, it is expected that the country will rely on imports for its future hydrogen needs. Being relatively densely populated, it is usually assumed that renewable energy generation cannot be built out enough to supply the energy needed for large-scale domestic green hydrogen production.

Norway is often named as a potential supplier of green or blue hydrogen for German industries. Yet, plans for a pipeline and large-scale blue hydrogen exports from Norway to Germany have been scrapped recently.

That Norled opted for a German supplier likely has to do with the fact that liquefied hydrogen is not exactly easy to come by. There are not many hydrogen liquefaction facilities, and none in Norway.

Leuna is a chemical complex in eastern Germany. Linde operates a hydrogen liquefaction plant in Leuna, which has been expanded in recent years. Linde's plant in Leuna is also an important supplier for hydrogen filling stations for fuel cell cars in Germany.

But Linde is, for the most part, not supplying green hydrogen from its plant in Leuna. It operates a steam reformer that produces hydrogen from fossil gas. Besides liquefying hydrogen, Linde also supplies that gray hydrogen to consumers within the Leuna chemical complex via a local pipeline grid.

In August 2024, a leak from a hydrogen trailer at Linde's liquefaction plant in Leuna caused an explosion. After the incident, many hydrogen filling stations in Germany were not operating, as hydrogen trailers of the same type were taken out of service due to safety considerations.

In the following months, all three owners of fuel-cell powered cars in Germany had to suffer major inconveniences. The often had to travel longer distances to refuel their emission-free cars with dirty gray hydrogen made from fossil gas. (Of course, I'm just kidding. Around 2,000 fuel cell cars are registered in Germany, which gives them an impressive market share of around 0.004 percent.)

Until recently, Linde had plans to expand their production of gray hydrogen and build a new steam reformer. According to an article in the local newspaper Mitteldeutsche Zeitung in early 2021, plans for the new steam reformer were scraped, and instead, Linde announced plans for a 24-Megawatt electrolyzer in Leuna. Shortly afterward, Linde announced its partnership with Norled.

Initially, Linde's electrolyzer was supposed to start production in 2022. But that did not happen. In June 2023, German public television station MDR reported that the plant still was not operational, but Linde refused to comment on the delays.

The technology for Linde's electrolyzer comes from the british company ITM Power. As MDR reported, ITM's 2022 annual report mentions some reasons: "Unfortunately, delivery of this project has been delayed due to a number of factors, including supply chain constraints, changes to Leuna's site requirements, and both manufacturing and testing delays."

Is Linde's electrolyzer operational today? That is a question nobody is willing or able to answer. Linde has not replied to questions about its project. Norled, which initially answered to some of my questions, did not reply to follow-up questions about the actual source of its hydrogen.

InfraLeuna, the company managing the chemical complex, avoids giving a clear answer and writes: "The 24 MW electrolysis plant will be commissioned gradually from 2025."

Linde's electrolyzer project received 15 Million Euro via public subsidies. Yet, even the institution responsible for these subsidies, the Ministry of Economics in the state of Saxony-Anhalt, was unable or unwilling to answer questions about the state of the project and referred me to Linde.

While it was difficult to figure out whether Linde's electrolyzers are operational yet, they certainly were not operational in 2023. However, once the MF Hydra started transporting passengers in 2023, the chemical company wrote in a press release: "Linde is supplying ferry operator Norled with clean hydrogen for the fuel-cell powered MF Hydra."

If Linde's Electrolyzer in Leuna was not operational, and Linde was delivering hydrogen from Leuna to the ferry in Norway, where did that clean hydrogen come from?

I was unable to get an answer to that question. It is possible that Linde buys clean hydrogen from other suppliers. It is also possible that Linde produces clean hydrogen elsewhere and uses some form of accounting scheme to nominally deliver clean hydrogen. Yet, due to the lack of a clear answer from any of the involved entities, that remains speculation.

Trucks transport LH₂ from Germany to Norway

I also asked Norled how hydrogen is actually transported from Germany to Norway. "We have a delivery by truck every third week," Norled's spokesperson Cathrine Gjertsen wrote. "When developing MF Hydra, we were told that hydrogen production in Norway would be happening in the near future, and the plan was to start using liquid hydrogen from a Norwegian supplier. Unfortunately, there is still no production of liquid hydrogen in Norway."

Trucks transporting hydrogen from Leuna in Germany to the ferry dock, which is located in the municipality of Hjemeland, need to travel more than 1,300 kilometers (around 800 miles). Considering the known difficulties handling boil-off losses during transportation and storage of LH2 and the fact that a trailer was leaking hydrogen at Linde's liquefaction plant in Leuna, one may wonder what the actual emission footprint of that transport is.

What is the point?

At least publicly, Norled seems to be happy with its hydrogen-powered, price-winning ship: "After its first few months in operation, the pioneering vessel MF 'Hydra' has proved that liquid hydrogen on ships is both possible and efficient. Experience shows that this is a technology and a fuel that can ensure that short sea shipping in Norway can be emission-free where batteries are not an option."

It is a puzzling statement. Liquefied hydrogen is almost certainly not particularly efficient. Turning electricity into hydrogen and converting it back into electricity in a fuel cell inevitably comes with losses that are higher than battery-electric solutions. Liquefaction and regasification come with additional losses.

Furthermore, Norled appears to argue that LH₂ is a technology suitable "where batteries are not an option."

The MF Hydra operates on routes only around 4-5 kilometers long. It seems implausible that those routes cannot be serviced more efficiently with battery-electric ferries. And Norled should have plenty of experience with it.

In 2015, the world's first battery-electric ferry MF Ampere started transporting passengers across the Sognefjord, connecting the municipalities Lavik and Oppedal. With around seven kilometers distance, that route is already longer than the route served by the MF Hydra. The MF Ampere is owned and operated by Norled.

It remains unclear what the purpose of the world's first ship running on liquefied hydrogen is. Larger battery-electric ferries transporting more passengers on longer routes already exist. Neither ferry operator Norled nor the Norwegian Public Roads Administration (NPRA, Statens Vegvesen), which provides funding for the MF Hydra, wanted to comment on its purpose.

Author: Hanno Böck

More

In 2022, I wrote an article about E-Methanol as a shipping fuel for the shipping news web page Fathom World. It is no longer online, which is why I am republishing these old articles one by one.

Regular readers will know that E-Methanol is a topic I follow closely. I have added some updates at the end of the article.

Brief

• Using fuel cells instead of combustin engines could avoid some of the problems of using ammonia as a shipping fuel. A research collaboration called ShipFC wanted to convert the Norwegian oil platform service ship Viking Energy to an ammonia fuel cell. Yet, that is probably not going to happen. The ShipFC project has been suspended, and Alma Clean Power, the company that was supposed to supply the fuel cell, has ceased its operations.

• Coolbrook, a company developing technology for high-temperature heat electrification, and Tenova, a technology provider for the metals and mining industries, have announced a partnership. The initial focus will be the integration of Coolbrook's technology into Tenova's acid regeneration plants. These acid regeneration plants are used to recover hydrogen chloride in steel production processes. Tenova is also known as one of the leading providers of direct reduction plants for steelmaking and supplies this technology to the Hybrit green steel project in Sweden.

• The direct air capture (DAC) industry is often accused of being a tool of the fossil fuel industry to delay real emission reductions. Recent developments certainly don't help to dispel that accusation: Oil company Occidental Petroleum, also known as Oxy, has bought Holocene, a leading provider of DAC technology. It is the second major DAC company now owned by Oxy, which previously also bought Carbon Engineering.