If business starts the transformation now, international maritime trade could be climate-neutral by 2050 without losing significant output.
So far, shipping has moved very little in the direction of sustainability. But technically and economically, climate neutrality could be achieved by 2050, a study now shows. Accordingly, ideal fuels would be synthetic methanol or ammonia. However, this transformation requires clear political direction in a timely manner. Experts consider the considerable additional costs to be unproblematic.
The international maritime trade respectively resp. The associated shipping could be climate-neutral from the middle of the century onwards. However, the groundwork for this would have to be laid now. This is the conclusion of a comprehensive analysis of this challenge. For the study published in the journal Nature Energy a research team from ETH Zurich analyzed the potential of different propulsion technologies and their economic consequences.
International shipping currently accounts for more than two percent of global greenhouse gas emissions and thus similar to the entire Federal Republic of Germany. Transport of goods by sea is predicted to triple by 2050 compared to 2015;CO2 emissions would increase by a similar amount. So far, similar to cross-border aviation, these emissions are not attributed to any state and are accordingly not accounted for in national climate targets. For this reason, too, it was an important signal that the global community should step up the pressure on the International Maritime Organization (IMO)- at the 2021 World Climate Summit the United Nations area responsible for shipping- has increased. In view of the rather gradual changes in the industry so far, many experts assume that ocean shipping will fail to make its contribution to the Paris climate protection targets. So far, it has only committed itself to reducing emissions by 50 percent by 2050 compared with 2008 levels.
Comparison of synthetic fuels
But what are the options for making maritime shipping carbon-neutral?? To assess this, the study looked at all intra-European transport journeys by bulk carriers and oil tankers. The experts then modeled for different fuels and propulsion systems whether the ships could use them to transport the same cargo over the same distance.
As possible fuels that can be produced in a climate-neutral way, the study considered green hydrogen, ammonia, liquefied petroleum gas, synthetic methanol, synthetic diesel and eco-electricity. The researchers ruled out biofuels, not least because of their insufficient availability. The conclusion of the analysis: ammonia and methanol have the greatest potential. While transport costs would double to six times, depending on the options chosen, according to the study. But this sounds more dramatic than it is, comments energy expert Martin Cames of the oko-Institut in Berlin, who was not involved in the study: "The costs of sea transport are marginal shares of the costs of products. In the past, there have been strong price fluctuations, both in marine fuel prices and in freight rates, without global trade coming to a standstill as a result.“ It is crucial that all ships are equally affected by the relevant regulations, the expert emphasizes. An impetus resulting from the costs to more local production, where this is possible, would also be welcome from a sustainability perspective.
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Almost the same transport performance would be possible
As far as the evaluation of fuel options is concerned, Cames sums up: "The results confirm previous findings and the estimates from our own analyses: hydrogen and electricity are practically out of the question for long distances in the period up to 2050, at best in niches such as ferries or in the area of coastal shipping.“ Diesel is not an option because of the high operating costs, nor is liquefied petroleum gas (LPG), which is opposed primarily for climate protection reasons due to potential methane leaks, which would counteract the idea of climate protection. Comparing the favored options of ammonia and methanol, the energy expert finds: "Ammonia is more cost-effective because it does not require direct CO2 extraction from the atmosphere.“ The disadvantages of ammonia over methanol are its handling, because it is toxic, and its lower energy density. In addition, there will probably be no ammonia engines before 2025. „Methanol is more expensive to produce, but its handling and energy density are cheaper, and there are already about 20 ships running on methanol.“
Without further adjustments to ships, ports and schedules, climate-neutral fuels would reduce the total transport performance of the ocean shipping industry studied by around one-fifth. However, if three percent of the load were replaced with carbon-neutral fuels, 93 percent of the current transport performance could be achieved; if six percent of the fuel were used, the total transport performance would actually be reduced by only one percent. However, this would require that the fuel load is always exactly matched to the route requirements, ideally through modular energy systems that are adjusted for each trip. It would be even better to make at least one stop for "refueling" and thus further reduce the space required for fuel.
Solvable challenge for ports
A particular challenge for ports could be to always stock different fuels in sufficient quantities. Spatially and technically, it probably wouldn’t be a problem. But Cames said it could lead to additional costs that were not adequately considered in the study. „Currently, 97 percent of maritime transport is based on petroleum-based fuels- plus three percent liquefied natural gas LNG. If this were spread over five e-fuels in the future, there would be huge infrastructure costs due to lower economies of scale.“ The decision as to which e-fuels will become established should not be left to the market, which takes too long to decide. „ÄAs with the decision in favor of battery-electric drives in road transport, the states must strive to limit the number of e-fuels to one, or at most two, as soon as possible.“ Regardless of the choice of fuel, this transformation would mean that the demand for eco-electricity would increase, because this is required for the sustainable synthesis of the climate-neutral fuels. In the analyzed scenario for Europe, the total electricity demand would increase by up to eight percent.
The authors of the study assume that their analysis can be applied to the entire maritime trade and thus to other ship types as well. However, experts who were not involved in the study, such as Jonathan Kohler from the Fraunhofer Institute for Systems and Innovation Research, consider this to be one of the few weak points of the analysis: "The authors examine the weight of the alternative fuels loaded and not their volume, criticizes Kohler. „Because e-fuels have a much lower volumetric energy density than fossil fuels, they require much more space on board. This is an important issue for shipbuilding, more important than weight.“ For container ships in particular, the analysis needs to be adapted, Cames agrees.
ÖEconomically interesting wind propulsion systems not considered
Nevertheless, Kohler considers the study’s conclusion to be too pessimistic from an economic point of view for two reasons: "First, the authors implicitly assume that ships will travel at the same speed as they do today.“ This could involve reducing speed by up to 50 percent, which would save a lot of energy everywhere. „And second, they don’t take into account wind propulsion, which generally produces no greenhouse gases and where ships need almost no additional fuel.“ It would save a lot of operating costs "potentially up to 30 percent, a stark contrast to e-fuels".
For laymen, the lower speed initially appears to be a disadvantage. But in maritime trade, it is much more important to be able to plan sailing times accurately than to keep their duration small. Although a longer trip slightly increases operating costs, Kohler criticizes. But the slower speed allows better route management, reducing waiting times at ports, locks or canals. On the one hand, this makes up for time and, on the other, reduces costs. Nevertheless, government support for the necessary technologies is certainly necessary, says Kohler.
Political direction needed now
In order to achieve climate-neutral shipping by 2050, political direction is therefore required in a timely manner, say the experts. Ships built today generally remain in service for 25 to 40 years. At the very least, therefore, they must be designed now in such a way that it will be possible to convert ships from fossil fuels to synthetic, climate-neutral fuels without any complications.