“A considerable challenge”: how maritime transport wants to make its 50,000 merchant ships less polluting

At the beginning of the year, announcements of ships and initiatives proposing to transform maritime transport are multiplying. It is not a coincidence. Since January 1, 2023, the approximately 50,000 merchant ships, which provide 90% of world trade by sea but represent 3% of greenhouse gas emissions, have been faced with tougher regulations from the International Maritime Organization. Decryption.

Baptized “Orient Express Silenseas”, the long setting of 54 cabins ordered by the Accor group from Chantiers de l’Atlantique, in Saint-Nazaire, unveiled on January 12, is a figurehead. Beyond the luxury embodied by the mythical surname, the one which in 2026 will be the largest sailboat in the world will illustrate the revolution in which maritime transport has entered, whether for cruises or goods. That of the course given towards zero greenhouse gas emissions at a speed that suddenly increases.

A luxurious cruise ship of more than 200 m, the “Orient Express Silenseas” will be built by Chantiers de l’Atlantique, in Saint-Nazaine, with sails and LNG engines.
Accor – © Maxime d’Angeac and Martin Darzacq

1 – Regulations: slow down or change

“I did not imagine that the IMO was going to restrict all the world’s shipowners to such an extent. The regulations are suddenly tougher and take everyone by surprise”, loose Nils Joyeux. The young entrepreneur, based in Lorient, founded Zéphyr & Borée to carry out innovation projects in the field of freight transport. In a joint venture with the shipowner Jifmar, the first of these projects touched down on January 13, in Guyana. “Canopée” will transport Ariane 6 elements for Arianespace, partly by sail, to Kourou, anticipating the next steps of the maritime regulations that came into force on 1er January.

The IMO, the International Maritime Organization, has decided to rate all merchant ships according to their carbon intensity. “What you pollute per tonne of goods transported and per kilometer travelled”, summarizes Nils Joyeux. To escape penalties, shipowners will have to choose: “Either you slow down, it’s the choice of sobriety, like in cars, or you adopt innovative technologies, which are expensive, and you will continue to drive at 130 km/h.”


The “Canopée” made its first crossing Saint-Nazaire – Guyana without a wing. It will be equipped with it by the spring.
Alizés – Zéphyr & Borée, Jifmar, VPLP

2 – The wind, immediate free energy

It is estimated that two-thirds of ships will have to gradually slow down while waiting for these innovations to mature and for the fleet to be renewed. One of them is ready: the sail.

Classic for Vela, inflatable at Wisamo, in glass-polyester and carbon on the “Orient Express Silenseas”. Wing format, as on “Canopée”, 4 x 363 m² erected on four masts, which “will provide a third of the propulsion”, on average, says Nils Joyeux under the umbrella of the Alizée joint venture. Or six in number on the Williwaw, this container ship designed by Zéphyr & Borée, of which a series of ten units will leave the shipyards from 2025 for “the Coalition of shippers. L’Occitane, Nestlé, Cointreau, Michelin, in particular”to which Geodis joined on Thursday.

These will be new boats dividing their greenhouse gas (GHG) emissions by 50%.

With its kite sail, the Nantes AirSeas, born in Toulouse, offers him, “a sailing solution adaptable to any existing vessel segment”indicates its general secretary Stéphanie Lesage, for a “gain of 20% on average” on CO2.


The “Ville de Bordeaux” equipped with a 250 m² test version of the AirSeas kite, during a crossing of the Atlantic.

A cousin of a paraglider wing, the AirSeas solution has been tested on the “Ville de Bordeaux” freighter since December 2021, between France and the United States.

From 500 m² in the long term, the sail will then assist the classic propulsion of boats up to 400 m, embracing the wind at 300 m height, where it is “more stable”automated for its handling and piloting. “It’s the most pragmatic solution to decarbonize right now” ships powered by heavy fuel oil, judge Stéphanie Lesage.

3 – LNG while waiting for e-fuels

More and more companies are switching to liquefied natural gas, which offers considerable savings on sulfur oxide, NOx and fine particles and around 20% on CO2. “It’s still a fossil fuel, admits Christine Cabau Woerhel, executive vice-president of CMA CGM, the world’s third-largest shipowner. But this is the beginning of the roadmap and the only industrial-scale solution available to date to initiate this transition, which is a considerable challenge.”

CMA CGM currently has 24 vessels running on LNG, including the

CMA CGM currently has 24 vessels running on LNG, including the “Jacques Saadé”, the largest container ship powered in this way.
Philippe Plisson

The Marseille-based company has 32 ships whose engines run on LNG, and has ordered six others running on methanol, an alcohol similar to ethanol. They all have – “we will have more than a hundred in 2026” – the ability to accept “less and less carbonaceous versions of these fuels”. Tomorrow methane from biomass, further away from 100% synthetic e-fuel, based on hydrogen and captured CO2, or ammonia.

“We are not going to replace all oilresumes Christine Cabau Woerhelby a single energy, but to advance as quickly as possible on the path according to what we can develop with research and industry.”

Optimizing its operations to reduce its consumption, relying on innovative start-ups, CMA CGM has set itself a net zero carbon ambition for 2050. And is counting on the emergence “of an ecosystem” which will have to supply renewable electricity and green hydrogen in considerable quantities. The first is necessary for the production of the second, which is a basic brick of these e-fuels… much more expensive.

4 – The fuel cell a realistic option?

Produced with renewable energy, hydrogen used in a fuel cell is the cleanest but “the more you decarbonize a fuel, the more space it takes up”, says Victorien Erussard, founder of Energy Observer. Storing it requires a lot more than fuel oil, not ideal for a deep-sea merchant ship, and it also needs to be liquefied. Victorien Erussard wears this “great technological challenge” in the form of a 150m coaster which he hopes will sail “in trials in 2026”.

Windcoop's sailing freighter will transport its hundred containers at a speed of 8 knots.

Windcoop’s sailing freighter will transport its hundred containers at a speed of 8 knots.

The spice route

Based in Méjannes-les-Alès, Arcadie has been distributing organic spices from production in France for three decades, but it also fetches them from India, Iran and Madagascar. And to reach the big island in the Indian Ocean, the company from Gard co-founded Windcoop, which will fit out a container ship designed by Zéphyr & Borée, 85 m long whose ambition is to sail 60% by sail from Marseille to Toamasina, on the east coast.

The company is finalizing the call for tenders for the ship, which will be able to move one hundred containers (1,400 t) at 8 knots and twelve passengers, reviving the languor of 19th century sailing ships heading towards the tropics on the trade winds route. First trip in 2025.

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