Knowledge

The future fuel for marine engines is not yet decided. However, it is well-known that utilizing green alternative e- fuels is a big step in the way of decarbonization. Dual-fuel (DF) engines offer great fuel flexibility with possibility of using different green gaseous e-fuels like methane and ammonia. The ignition of the lean premixed gaseous fuel in a DF engine depends on the auto-ignition of the injected pilot diesel fuel. Therefore, a proper auto- ignition of the pilot diesel is important in these engines. In the present study, large eddy simulation is carried out to study the auto-ignition process of pilot diesel in premixed methane-diesel DF combustion in a constant volume combustion chamber. The entire DF combustion processes involving methane injection, methane/air mixing, pilot diesel injection, and ignition are simulated. The numerical model is validated against experimental data. The base case has a pilot diesel injector with 8 nozzle holes. The auto-ignition process in two other cases with 4 nozzle holes are investigated and compared with the base case. Considering same amount of pilot fuel, the injection rate is assumed to be double in one the cases, while in the other case, the injection duration is doubled. The results show that the ignition process in the case with 4 nozzle holes and double injection rate is incomplete due to flame impingement on the walls. However, a reduction of the nozzle hole numbers can improve diesel pilot ignition in the case with 4 nozzle holes and double injection duration. The higher fuel mass per orifice leads to an increased fuel concentration within the diesel pilot sprays and higher combustion rate than the base case. Furthermore, more confined spray envelope in the case with double injection duration leads to an increased reactivity and more efficient auto-ignition process than the case with double injection rate.

This report is a background report to the MarE-Fuel project financed by the Maritime Fund and the Lauritzen Fund. Partners of the project has been DTU, Anker Invest, Mærsk Line, Copenhagen Economics, OMT and DFDS. In the report, potential decarbonization roadmaps or pathways for the maritime industry are presented, as well as the methodology of deriving them. Different future fuels and their emissions are highlighted. In addition, biomass availability plays an essential role in climate mitigation efforts towards net-zero by 2050, and thus we examined different biomass availability scenarios alongside greenhouse-gas emissions cap scenarios. The assumptions related to the underlying emissions can be found in the first chapter of the report. Besides the underlying emissions for a decarbonized maritime industry, the ship stock and the underlying transport demand play an essential role for a future decarbonized maritime industry. In the second chapter of the report, we address this issue by explaining how ship stock and shipping demand have been incorporated into the model. Finally, we present the optimization ship stock model developed to generate roadmap scenarios. We show the objective function and the underlying constraints of the model. The results of this work are presented and discussed. We also show some sensitivity analysis, which will shed light on the relevant parameters for the futureof the maritime industry. Our main findings can be found in the end of the report.

As the emission legislation becomes further constraining, all manufacturers started to fulfill the future regulations about the prime movers in the market. Lean-burn gas engines operating under marine applications are also obligated to enhance the performance with a low emission level. Lean-burn gas engines are expressed as a cleaner source of power in steady loading than diesel engines, while in transient conditions of sea state, the unsteadiness compels the engine to respond differently than in the steady-state. This response leads to higher fuel consumption and an increase in emission formation. In order to improve the stability of the engine in transient conditions, this study presents a concept implementing a hybrid configuration in the propulsion system. An engine model is developed and validated in a range of load and speed by comparing it with the available measured data. The imposed torque into the developed engine model is smoothed out by implementing the hybrid concept, and its influence on emission reduction is discussed. It is shown that with the hybrid propulsion system, the NOX reduces up to 40% because of the maximum load reduction. Moreover, eliminating the low load operation by a Power Take In during incomplete propeller immersion, the methane slip declines significantly due to combustion efficiency enhancement.

I this video, Associate Professor Anders Ivarsson (DTU Mechanical Engineering) present the current status of their projects and experimental capabilities in the field of green marine fuels (lignin fuel, ammonia, and dimethyl ether) in their combustion engine laboratory.
The session was developed in collaboration with MARLOG.

Det Blå Danmark har en ambition om at være et internationalt foregangsland for klimavenlig skibsfart. Omstillingen til en mere bæredygtig skibsfart er dog en stor udfordring, der vil kræve betydelige investeringer i både ny teknologi, skibe og energiinfrastruktur og en systemisk tilgang til samarbejde på tværs af sektorer og mulige aftagere af grønne brændstoffer. Med denne rapport præsenterer DTU resultatet af et arbejde i at kortlægge forskningsmulighederne for Grønne Brændstoffer i det Blå Danmark. Arbejdet har afdækket, at der er behov for forskning på tværs af systemer og over hele værdikæden. Kortlægningen er lavet med viden fra DTU forskere samt input fra industrien og brancheorganisationerne.

Rapporten præsenterer en kortlægning af udfordringer forskningsbehov og rammebetingelser, som kan medvirke til at understøtte potentialet for grønne brændstoffer i det Blå Danmark. Kortlægningen er afrundet med anbefalinger til forskningsbehov inden for udvalgte områder samt uddannelse og test- og demonstrationsprojekter. Det er vores håb, at rapporten kan være med til at sikre det Blå Danmark en plads helt fremme i førerfeltet inden for bæredygtig skibsfart i mange år endnu.

Several replacement fuel to today’s fossil based ship propulsion fuels have been addressed in MarEfuel. Key ones are; pyrolysis oil (blend in fuel), methanol and ammonia. These were singled out among many possible fuels from a preliminary analysis that indicated that they could play a key role in fulfilling the emission targets set politically and by the sector in the most cost effective manner. In the following they shall be treated in turn in some detail. Costs of several “blue” fuels have also been assessed. The projected costs are used in other parts of the MarEfuel project (e.g. for assessing the total cost of ownership).

The maritime sector is a key asset for the world economy, but its environmental impact represents a major concern. The sector is primarily supplied with Heavy Fuel Oil, which results in high pollutant emissions. The sector has set targets for deacrbonisation, and alternative fuels have been identified as a short-to medium-term option. The paper addresses the complexity related to the activities of the maritime industry, and discusses the possible contribution of alternative fuels. A sector segmentation is proposed to define the consumption of each sub-segment, so to compare it with the current alternative fuel availability at European level. The paper shows that costs and GHG savings are fundamental enablers for the uptake of alternative fuels, but other aspects are also crucial: technical maturity, safety regulation, expertise needed, etc. The demand for alternative fuels has to be supported by an existing, reliable infrastructure, and this is not yet the case for many solutions (i.e. electricity, hydrogen or methanol). Various options are already available for maritime sector, but the future mix of fuels used will depend on technology improvements, availability, costs and the real potential for GHG emissions reduction.

The reduction of Greenhouses gasses (GHG) and other air emissions represents a major challenge for ports. The world over, however, ports vary considerably in their efforts to reduce air emissions, and the causes for this variation remain under-researched. This paper examines the drivers for the adoption of air emissions abatement measures in a sample of 93 of the world’s largest ports, covering all continents and mobile emitters. We test five hypotheses with a Linear Probability Model to disentangle the impacts of key port characteristics on the current adoption of abatement measures and identify three key drivers for adoption: Population density, the port landlord business model, and a specialization in servicing container shipping. We also find that ports are more likely to implement specific bundles of measures, in particular combining pricing and new energy sources. Our work has implications for ports, as we suggest that they should coordinate abatement efforts to achieve effectiveness in their work.

Maritime transport carries around 80% of the world’s trade. It is key to the economic development of many countries, it is a source of income in many countries, and it is considered as a safe and environment friendly mode of transport. Given its undisputed importance, a question is what does the future hold for maritime transport. This chapter is an attempt to answer this question by mainly addressing the drive to decarbonize shipping, along with related challenges as regards alternative low carbon or zero carbon marine fuels. The important role of maritime policy making as a main driver for change is also discussed. Specifically, if maritime transport is to drastically change so as to meet carbon emissions reduction targets, the chapter argues, among other things, that a substantial bunker levy would be the best (or maybe the only) way to induce technological changes in the long run and logistical measures (such as slow steaming) in the short run. In the
long run this would lead to changes in the global fleet towards vessels and technologies that are more energy efficient, more economically viable and less dependent on fossil fuels than those today. In that sense, it would have the potential to drastically alter the face of maritime transport in the future. However, as things stand, and mainly for political reasons, the chapter also argues that the adoption of such a measure is considered as rather unlikely.