We present a solution method for the liner shipping network design problem which is a core strategic planning problem faced by container carriers. We propose the first practical algorithm which explicitly handles transshipment time limits for all demands. Individual sailing speeds at each service leg are used to balance sailings speed against operational costs, hence ensuring that the found network is competitive on both transit time and cost. We present a matheuristic for the problem where a MIP is used to select which ports should be inserted or removed on a route. Computational results are presented showing very promising results for realistic global liner shipping networks. Due to a number of algorithmic enhancements, the obtained solutions can be found within the same time frame as used by previous algorithms not handling time constraints. Furthermore we present a sensitivity analysis on fluctuations in bunker price which confirms the applicability of the algorithm.
This study proposes a novel tower damping system to enhance the structural performance of the NREL 5 MW semi-submersible wind turbine under operational and extreme load conditions. Environmental load data from the Norwegian MET center was analyzed to characterize the loading conditions for floating offshore wind turbines (FOWT). The probability density spectrum of sea state data was employed to identify operational load conditions. At the same time, the Inverse First-Order Reliability Method (IFORM) was utilized to derive the 50-year extreme sea state. Perform a fully coupled Aero-Hydro-Servo-Elastic simulation of the FOWT dynamic model with a damping system using OrcaFlex software. The results reveal that: Under operational sea states, the turbine tower-top displacement was reduced by 60–70%, and acceleration by 30–40%, enhancing tower-top stability. Under extreme loads, tower-top acceleration was reduced by 5–7%, and displacement by 6–8%. Cumulative damage assessments indicate a reduction in fatigue damage of up to 72%, with the effective fatigue life of the tower base extended by 136%. The proposed damping system significantly reduces vibration under fatigue and extreme load conditions.
This report is in the context of the DMA-DTU project on Market Based Measures (MBMs) The aim of this project is to provide an overview and discussion of potential Market Based Measures under the Initial IMO Strategy for the reduction of green house gas (GHG) emissions from ships. In this context, some related developments are also seen as directly relevant to the scope of the project, mainly in the context of the possible inclusion of shipping into the EU Emissions Trading System (ETS). In 2010 an Expert Group was appointed by the IMO’s Secretary General after solicitation of member states and was tasked to evaluate as many as eleven (11) separate MBM proposals, submitted by various member states and other organizations. All MBM proposals described programs and procedures that would target GHG reductions through either ‘in-sector’ emissions reductions from shipping, or ‘out-of-sector’ reductions via the collection of funds to be used for mitigation activities in other sectors that would contribute towards global reduction of GHG emissions.
This report provides a current assessment on the prospects for aerial drone applications onboard ships. Three use cases are each forecasted to their time to implementation and evaluated as an opportunity for the maritime and offshore industries. The report's findings are based on respondents' answers to surveys about the three use cases. The data for this report is based on desk research and an analysis of survey responses. The report is produced by the PERISCOPE network.
Rapporter fra flere globale miljøinstitutioner, her
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under den internationale science-policy platform
om biodiversitet og økosystemtjenester (herefter
IPBES), understreger behovet for genopretning af
økosystemer (1,2). Den seneste globale IPBES-rap
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port fra maj 2019 peger således på, at forringelser
af økosystemer på land og i havet underminerer
livsgrundlaget for 3,2 milliarder mennesker. Gen
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opretning bliver fremhævet som en af de vigtig
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ste handlemuligheder for effektivt at begrænse
tabet af biodiversitet og forbedre livsgrundlaget
for os mennesker ved at imødegå forringelser for
en række økosystemtjenester. Det nuværende årti
2021-2030 er af UNEP udpeget til årtiet for genop
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retning med det formål at genetablere ødelagte
eller forarmede økosystemer verden over.
IPBES rapporterne dokumenterer, at biodiversi
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tetskrisen er en altomfattende og global udfor
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dring, og at krisen er på linje med klimakrisen. De
tiltagende klimaændringer er ligeledes en af ho
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vedårsagerne til tab af biodiversitet (2). Der er af
hensyn til begge kriser behov for, at der beskyttes
og genetableres velfungerende og uforstyrrede
økosystemer. Der bør derfor ske en national ud
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møntning af resultaterne fra de internationale aftaler baseret på den bedst tilgængelige viden.
Rapporten præsenterer resultaterne af forskningsprojektet "Værdier og Normer for Grøn Omstilling i Det Blå Danmark", der har undersøgt de kulturelle og sociale betingelser, som medlemmer i branchen oplever enten understøtter eller står i vejen for grøn omstilling i den danske skibsfart og de tilknyttede sektorer og organisationer.
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.