© Martin Damboldt/Pexels
According to data from the 2022 IPCC report, “ maritime transport represents 16 % of freight emissions and 70  ;% of ton-kilometers transported (i.e. the movement of one ton of goods over one kilometer) » reminds us of this article from Greenly. Like that of aviation, the sector is frequently singled out because of its very heavy ecological impact.
Most container ships traveling on our oceans run on heavy fuel oil (HFO), a residue from the distillation of crude oil that is much cheaper than lighter fuels such as marine diesel or liquefied natural gas (LNG). A fuel that Morten Bo Christiansen (key player in the fight against carbon emissions within the shipping industry and senior vice president at A.P. Moller-Maersk) describes as “ < em>the bottom of the barrel “.
New regulations put in place by the Organization international shipping aims to reduce sulfur and carbon emissions, leading industry players to explore the viability of alternative fuels.
Methanol, a promising alternative
Let's take the example of the Laura Maersk (see video below), a $160 million sea giant which set sail in 2023 to sail the Baltic Sea. This ship differs from its predecessors by one particularity: it runs exclusively on methanol, an organic component which is also the simplest of alcohols.
Unlike traditional fossil fuels, methanol offers significant environmental benefits when produced sustainably. Indeed, its manufacture can be carried out by capturing gas from landfill sites or by processes powered by renewable energies. This new approach makes it possible to considerably reduce polluting emissions.
It is not perfect, but remains entirely possible as a substitute for HFO. The craze for methanol in the field of maritime transport is rather palpable: more than 200 ships compatible with this alternative fuel are currently on order around the world.
Subscribe to Lemon Squeezer
L’ammonia : clean, but complex to use
Ammonia presents itself as an alternative fuel, also with potential. It is one of the most synthesized substances in the world and is used in many fields: agriculture, chemical industry, refrigeration, water treatment and also as an energy vector. Its big advantage: many ports around the world already have ammonia supply structures.
However, its adoption in the transport of Sea freight can be a little complex, especially due to its toxicity and the difficulties associated with its combustion. In fact, it requires very high temperatures (around 650°C, compared to around 60°C for HFO). However, Lars Tingbjerg Danielsen of MAN Energy Solutions emphasizes that many efforts are being made to overcome these obstacles.
One of the major areas of current improvement is the development of more efficient and more reliable engines allowing combustion of the ’ ammonia at high temperature. It requires very slow engines to burn properly, otherwise it may escape. The risk of contamination is then quite significant. The goal is to stabilize this process in slow two-stroke engines of large ships.
To do this, Danielsen's company is studying the ;#8217;ignition of ammonia in engine blocks using high-speed cameras. This allows engineers to understand and optimize the ignition and combustion processes while maximizing their safety.
Hydrogen: a candidate hampered by technical and economic challenges
On paper, hydrogen seems to be the ideal alternative fuel. Indeed, its combustion only emits water vapor (which still remains a greenhouse gas) and it appears to be impeccable from an ecological point of view.
In reality, using it in maritime transport means encountering major obstacles, both technically and economically. Christiansen points out that although hydrogen can be produced in a renewable way (green hydrogen), its physical properties greatly complicate its exploitation. The problem with hydrogen is that it evaporates at a very low temperature (-235 °C).
To liquefy it and keep it stable, huge amounts of energy are required. Even if many companies are currently working on alternatives to hydrogen storage (in the form of a solid bar or powder for example), the perfectly adapted solution does not yet exist.
In addition to this, the hydrogen molecule is one of the smallest molecules in existence. This means he can escape very easilyby the slightest crack, posing significant efficiency and safety problems. Despite Maersk's efforts to explore its full potential, hydrogen has proven to be more expensive than methanol and ammonia. The latter are therefore the most promising candidates at the moment.
For the industry maritime, the situation is pressing: it must reduce its carbon emissions by at least 30% by 2028 to respect the commitments made under the Paris climate agreement. Simon Bullock, climate and maritime transport specialist, insists on the urgency of the situation: the slightest delay would make “ almost impossible » for shipping companies to achieve their decarbonization objectives. An observation that he shared in this publication. The clock is ticking and the adoption of alternatives by shipowners is proving essential.
- Methanol is a promising fuel for the maritime industry, if produced sustainably.
- L’ammonia also, but its adoption still merits adjustments in the mechanics of container ship engines.
- L’hydrogen, the last candidate, is for the moment the one with the least of potential, even if specialists are interested in it.
📍 To not miss any news from Presse-citron, follow us on Google News and WhatsApp.
[ ]