The purpose of this paper is to revisit speed optimization and speed reduction models for liner shipping in a multi/flexible fuel context with regards to the current ongoing speed limit debate at the International Maritime Organization (IMO). The focus is mainly on analyzing the influence of a maximum average speed limit on the optimal speeds, carbon intensity and emissions in conjunction with fleet deployment for dual fuel (DF) Neopanamax container vessels utilizing liquefied natural gas (LNG).
Global warming and, correspondingly, reducing CO2 emissions is one of the most challenging tasks the world faces today. The maritime industry contributed to 2.89% of the global anthropogenic CO2 emissions. To decrease this share, the International Maritime Organization (IMO) defined, among others, the goal to reduce the carbon intensity of international shipping by 40% until 2030. In this context, the short-term measures recently adopted, in the form of a technical standard (Energy Efficiency Existing Ship Index, EEXI) and a rating scheme based on an operational indicator (Carbon Intensity Indicator, CII), mark a crucial step to achieving the mentioned goal. In addition, the EU Commission has recently introduced the FuelEU Maritime Initiative limiting the annual greenhouse gas (GHG) intensity of a ship’s energy use incorporating a reduction occurring in a five-year rhythm between 2025 and 2050. The paper investigates the practical options availed to existing containerships of different sizes and technological vintages for meeting the specific EEXI, CII, and GHG intensity reduction requirements imposed by the regulations. The investigation will be based on the actual technical and operational profiles of six sample ships and will consider a set of possible compliance options including, but not limited to, engine power limitation, waste heat recovery system, variable frequency drives, and virtual arrival. The data used originates from noon reports of existing containerships provided by a European industry leader. The ship-specific CO2 emission reduction potentials required for the impact assessment result from either literature or actual data-based calculations. Financial data is used for investigating the economic impact of the reduction requirements. Conclusions drawn include an operational advantage that pre-EEDI ships enjoy when applying engine power limitation (EPL) for EEXI compliance, the occurrence of payback periods exceeding ship lifetimes, and an estimate of the effect that onshore power supply can have on complying with the FuelEU Maritime Initiative.
We consider a variant of the berth allocation problem-i.e., the multi-port berth allocation problem-aimed at assigning berthing times and positions to vessels in container terminals. This variant involves optimizing vessel travel speeds between multiple ports, thereby exploiting the potentials of a collaboration between carriers (shipping lines) and terminal operators. Using a graph representation of the problem, we reformulate an existing mixed-integer problem into a generalized set partitioning problem, in which each variable refers to a sequence of feasible berths in the ports that the vessel visits. By integrating column generation and cut separation in a branch-and-cut-and-price procedure, our proposed method is able to outperform commercial solvers in a set of benchmark instances and adapt better to larger instances. In addition, we apply cooperative game theory methods to efficiently distribute the savings resulting from a potential collaboration and show that both carriers and terminal operators would benefit from collaborating.
Stricter regulations imposed on emissions are motivating the scientific community to consider studying alternative fuels to achieve low emission, high efficient dual-fuel (DF) marine engines. In this context, three dimensional computational fluid dynamic (CFD) simulations are performed to study the combustion and emission formation under two-stroke, dual-fuel marine engine-like conditions. The DF engine configuration consists of a pilot diesel fuel and a high-pressure, direct injection (HPDI) of natural gas (NG). The simulation results are validated under both high load (high charge density) and low load (low charge density) operating conditions. Detailed analysis of the flame development and emission formation are performed. The interaction between the pilot diesel jets and the methane flame jets is studied. Based on the results, the further methane jets penetration in the low load case leads to better air–fuel mixing and a higher combustion intensity than that in the high load. Effects of the pilot fuel injection timing on combustion and emission formation and the governing mechanisms are also investigated in detail. Results indicate that the intense combustion of the accumulated methane expands the methane flame towards the piston when the pilot injection timing is retarded. The NO formation is lower in the high load case with higher charge density due to the lower combustion intensity. Also, retarding the pilot injection timing decreases the NO formation.
The global society faces an existential threat if it fails to meet current and future material needs of its populations, while staying within the carrying capacity of our planet. An approach that has been put forwards to address this complex challenge is to aim to close our society's material flows through introduction of a Circular Economy (CE). This paper provides an extensive literature review to understand the evolution of material circularity concepts and strategies, and their potential for increasing material efficiency and reduce environmental impacts towards meeting the material needs of our societies in an environmentally sustainable manner. Based on the review it can be concluded that CE may have a strong potential to help address the challenge. However, this requires broadening the focus of CE from technical and economical to political and socio-cultural dimensions, adopting a whole-systems approach, aiming to redesign economic and social relations to not just reduce the impact humanity has on the environment but actually achieve a balance in human-nature relations with a planetary boundary thinking. Pursuing purely technical and economic avenues to implement CE for increasing material circulation and sustainable growth on the foundation of our current linear economic system, will not achieve its full potential. It will not be sustainable but continue to produce the challenges that we currently have.
The estimation of the thrust deduction fraction is generally conducted in ideal weather conditions. However, the presence of waves considerably alters the magnitude of this propulsive coefficient. The increased load of the propeller could be the main cause for the variation of the thrust deduction fraction in realistic operating conditions. In this work, load-varying self-propulsion model-scale numerical simulations in calm water conditions for the same ship speed are performed to investigate the influence of the propeller loading on the thrust deduction fraction. The single screw model-scale KVLCC2 tanker is selected as the case study. The results reveal a non-linear inverse correlation between the thrust deduction fraction and the propeller loading. A comparison with model-testing conducted on the KVLCC2 tanker in regular head waves suggests that the propeller loading is the main factor influencing the magnitude of the thrust deduction fraction in waves for the considered case vessel.
Ecosystems are viewed as important sources of innovation. While contracts, rules, policies, and industrial standards have been identified as important for coordinating and aligning inter-firm relationships, tools for the collective, collaborative orchestration of ecosystems have yet to be fully identified and articulated by scholars. The core contribution of this paper, the authors contend, is that corporate foresight tools, as applied at the level of the ecosystem, have the potential to orchestrate ecosystems. To this end, the authors examine the practical use of corporate foresight tools, in this case, roadmapping and scenario planning, as employed by ECOPRODIGI, an Interreg Baltic Sea project designed to advance the EU's strategy for eco-efficient Sustainable Blue Economy in the Roll-on/Roll-off (Ro-Ro) shipping ecosystem. Results demonstrate how ecosystem-level foresight significantly differs from traditional foresight centered around a focal firm. Corporate foresight tools, as applied to an ecosystem: 1) Target a diverse set of ecosystem actors beyond the segment's focal firm, including complementary firms, investors, and non-market actors; 2) Engage ecosystem actors, rather than only the focal firm, in shared strategy development based on a diverse mix of foresight tools; and 3) serve to orient and reify the ecosystem by charting the collective anticipation of innovations, policies, etc., in a shared set of future options. In the end, the authors find that corporate foresight tools operate as constitutive elements of ecosystems, that is, the tools help enact the ecosystem not as an abstract concept but as a shared, lived reality.
Autonomous marine surface vehicles rely on computer systems with computer intelligence making decisions to assist or replace the navigating officer. A fundamental requirement for the design and implementation of such a cyber-physical system is seamless, predictable, and secure interoperability between vendor-specific hardware and software subsystems. The article describes a system design that includes mechanisms to mitigate the risks and consequences of software defects, individual component malfunction, and harmful cyber interference. It addresses international regulations in the field and demonstrates a system design that can meet the requirements for safe behaviour in foreseeable events while also having the ability to call for human assistance if the autonomous system is unable to handle a situation. The paper presents a design for highly automated vessels with several inherent risk-reducing features, including the ability to isolate and encapsulate abnormal behaviours, built-in features to support resilience to unexpected events, and mechanisms for internal defence against cyber-attacks. The article shows how this is provided by a novel middleware that supports risk mitigation, dependability, and resilience.
Taking concrete steps towards a carbon-free society, the Danish Parliament has recently approved the establishment of the world's first two offshore energy hubs on Bornholm and on an artificial island in the North Sea. Being the two first-of-their-kind projects, several aspects related to the inclusion of these “energy islands” in the current market setup are still under discussion. To this end, this paper presents a first large-scale impact analysis of offshore hubs on the whole European power system and electricity market. Our study shows that energy hubs in the North Sea contribute to increase social welfare in Europe. However, when considering the impact on each country, benefits are not shared equally. To help the development of such projects, we focus on the identification of the challenges arising from the hubs. From a market perspective, we show how exporting countries are affected by the lower electricity prices and we point at heterogeneous consequences induced by new transmission capacity installed in the North Sea. From a system point of view, we show how the large amount of wind energy stresses conventional generators, which are required to become more flexible, and national grids, which cannot always accommodate large imports from the hubs.