Marine hydrogen
a long time in the making

More containers but less GHGs¹: a paradoxical challenge

Who hasn't been surprised or concerned by the vast Tetris-like formations of neatly stacked containers in major commercial ports? These giant multicoloured building blocks keep multiplying, driven by globalisation. According to the International Maritime Organization (IMO), global freight has increased from 2.6 billion tons in 1970 to over 12 billion tons in 2024. Today, 50,000 cargo ships and tankers navigate the seas, transporting 90% of global trade and responsible for 3% of total greenhouse gas emissions. According to the IMO, if no changes are made, this trajectory will drive that percentage up to 17% by 2050.

There are not multiple options for progress. Reduce the volume of commercial trade? Humanity's appetite for this activity seems unstoppable, and the victory count of the "local" apostles over the "global" ones remains at sea level altitudes. So, let's take a look at smart ships. Optimising ship loading, developing more economical routes by surfing currents and winds? AI, weather forecasting, and satellite imaging are working on this, yielding interesting results, but unfortunately with only marginal gains.

Ultimately, there are the green ships with their alternative, carbon free energies. For several years now, cargo ships equipped with sails have been navigating not the imaginary seas of science fiction authors, but the very real waves of the oceans. Cargo fleets have begun their sail-powered transformation and claim energy savings of 10 to 20%, as exemplified by "Grain de Sail " or "Hisseo", for whom a certain slowness in delivery has become a selling point.

Can the green ship break free from fossil fuels, leave the port of Utopia, and reconcile a clean maritime environment with happy globalisation? It's just a matter of time.

Fortunately with hydrogen there’s hope in the mix!

The maritime industry is hiring and has a position open for alternative fuel. Hydrogen, the smallest atom in Mendeleev's classification, sitting at the top left of the periodic table, and yet the most abundant in the universe (75% of its estimated mass), is a very serious candidate. With its single proton and single electron², this atomic dwarf used as fuel, combined with oxygen as an oxidiser, produces a clean explosion capable of running an engine, thus becoming a green giant since only water will be emitted... not a single mole of GHG.

There’s a second possibility which is even more virtuous: the fuel cell, an electrochemical generator that has sparked the interest of many researchers worldwide for several decades. Hydrogen injected into this device produces a current to charge batteries or power an electric motor, emitting only water. Additionally, Europe has placed e-fuels³ on a promising trajectory.

In theory, with hydrogen, Homo ecologicus possesses an alternative energy source not only for maritime use but also for mobility in general - a versatile source producing no GHG emissions. How did we not know this?

«I have problems for your solutions »

In physics, apparent simplicity often comes with hidden complexity. In its natural state on the blue planet, hydrogen is very rare; its production by electrolysis or steam reforming is energy-intensive and emits GHGs, and its transport and storage are delicate and costly, hindering the profitability of the entire sector and throwing cold water on our hopes. While the hydrogen engine boasts a respectable efficiency close to 40%, the combination of hydrogen production by electrolysis with the best fuel cell to generate electric current gives a poor overall efficiency of 20%. It may all may look beautiful but is somewhat capricious. In summary, hydrogen fascinates GHG hunters but struggles to convince industrialists. "Hydrogen is primarily a means of storing electrical energy," Pierre Marlinge reminds us. "Its traditional 'production-transport-consumption' chain is not yet fully structured, and the price per kilogram of hydrogen remains too high to drive demand, even if a mature supply existed," he adds.

Emerging, developing, structuring. The birth of a local industry

The glass (of hydrogen), may not yet be full but it’s not half empty either. Hynova Yachts (La Ciotat) has developed the world's first hydrogen day boat, and NepTech (Aix-en-Provence) has designed H2-ready passenger shuttles. "The hydrogen engines developed for buses and trucks are suitable for the needs of boats of this size, accommodating up to 200 passengers and 20 tons of cargo for NepTech's largest unit," comments Pierre Marlinge. "For this type of vessel, the obstacles come from the lack of refuelling infrastructure. Ports must meet demanding environmental and regulatory requirements. The lack of space on the docks makes it difficult to set up hydrogen distribution stations. The regulations need to evolve. In the absence of operational feedback, the organisations that certify this type of vessel (CRS) rely on requirements inherited from regulations for very large ships, which increases the cost of the boat."

Hynova Yachts has created EPHYRA to provide its clients with a complete solution of boats and charging stations. NepTech, with its H2-ready concept, allows for easily swapping a conventional engine for a fuel cell solution when the time comes. eHP2, a co-winner of the France 2030 initiative, is making waves with its hydrogen engine, designed for aviation but also attracting the interest of shipyards.

…but also on an international level

The renowned Dutch shipyard Feadship, announced in May 2024 the launch of "Project 821" a 120m yacht powered by 16 fuel cells and equipped with a hydrogen tank maintained at -253°C. Rumour has it that this luxurious vessel was sold for 600 million euros to Bill Gates, the iconic Microsoft founder turned climate activist. This event, which has the appearance of a marketing coup, nevertheless shows that marine engineering is gaining momentum on the hydrogen front. Lyon-based SAPAIC MOTEURS BERNARD is working on developing a one-megawatt engine, compared to the 300-kilowatt power currently used in buses and trucks. "Currently, there is a lack of test benchmarks wide-ranging enough for engines with a power of one megawatt or more. This is another obstacle to the development of combustion engines for maritime use," explains Pierre Marlinge.

The cruise line PONANT has unveiled its Swap2Zero project, set to launch in 2030. This ocean liner aims for zero GHG emissions during navigation, manoeuvring in port and at anchor. Relying on six breakthrough technologies, its designers have envisioned a virtuous mix, combining wind and solar power with decarbonised and non-fossil energies based on fuel cells.

Meanwhile, the Energy Observer 2 demonstrator, combining sail propulsion and hydrogen, is intended as a preview of the cargo ships of the future. "With #EnergyObserver2, we aim to bring together the best industrial players and develop a versatile, medium-sized transport vessel that operates without GHG emissions," said Victorien Erussard, CEO of the project, at the latest One Ocean Summit in Brest. "Our members are also innovating to optimise the energy consumption of onboard services: hot water, air conditioning, cooking, etc.," notes Pierre Marlinge.

Reducing hydrogen transport costs: e-fuels

The transport of pure hydrogen requires compressions around 700 bars or temperatures close to -250°C, necessitating a significant energy expenditure and hindering the profitability of the operation. Combining hydrogen with other elements changes the paradigm. For example, ammonia (NH3), consisting of 1 nitrogen atom and 3 hydrogen atoms, can be transported safely under normal temperature and pressure conditions. Recently, American chemists from Princeton and Houston have developed a process using standard LEDs, which is extremely energy-efficient, to separate nitrogen from hydrogen by breaking the NH3 bonds. A startup, Syzygy Plasmonics is already industrialising the process.

Meanwhile, Pierre Marlinge points out that "the American giant AIR Product, the equivalent of Air Liquide in France, has just launched the NGHC project, NEOM Green Hydrogen Company in Saudi Arabia." This $8.4 billion investment near the Neom site, the Saudi city of the future, will create the world's largest green ammonia production unit, powered by massive solar and wind farms. 600 tons of green hydrogen produced daily by seawater electrolysis, then combined with nitrogen (the most abundant component in the atmosphere) obtained from an air separation phase, will generate 1.2 million tons of ammonia annually. The valuable liquid will then be transported by tanker (hydrogen-powered?) to Rotterdam, where it will be handled by a mega factory using an LED process to separate the molecule into hydrogen and nitrogen. The hydrogen will then be distributed to Dutch and European consumers.

Change the suffix «carbon» into «gen», but above all keep « hydro »

The path to green and economical hydrogen remains tortuous, but when necessity dictates, research, industry, and public authorities, beyond borders and barriers, find ways to cooperate. Ultimately, harnessing hydrogen benefits knowledge, industry, and the economy, and who knows, it may contribute to a geopolitics imbued with more humanity. Isn't that the justification for crises?

Furthermore, fossil fuels, as their name suggests, come from nature's trash. Shifting from hydrocarbons to water means exchanging carbon for oxygen to (re)discover hydrogen, trading a life-threatening element for a life-giving one. Is it a choice? Rather, it is an obvious solution.

¹ The acronym GHG refers to Greenhouse Gases.

² Excluding isotopes such as deuterium or tritium.

³ Synthetic fuels, known as "e-fuels", are produced from renewable or low-carbon electricity, carbon dioxide or nitrogen in the case of e-ammonia, and hydrogen from electrolysis.