Simulation model of a ship’s energy performance and transportation costs
Doktorsavhandling, 2020

Society faces a major challenge to reduce greenhouse gas emissions to limit the effects and propagation of climate change. As the main contributor to global trade, the shipping industry adds significantly to global greenhouse gas emissions and must actively work towards reducing, or eliminating, emissions in a short period.  This thesis contributes by developing a generic model for quick and accurate prediction of the fuel consumption of existing ships or newbuilds in operational conditions. The aim is to be able to predict the potential of fuel-saving measures, e.g., design features, retrofitting, alternative propulsion, and operational improvements, and evaluate the impact of such measures both, logistically and technically.

A novel energy systems model called “ShipCLEAN” was developed, which provides the opportunity to predict the propulsion power, fuel consumption, and daily costs and income of ships in realistic operational conditions, i.e., a wide variety of drafts, speeds, and environmental conditions. ShipCLEAN is a unique coupling of a generic power prediction model and a marine transport economics model. Aside from a calm-water power prediction based on empirical and standard series methods, the power prediction model includes simulating alternative propulsion methods (i.e., wind-assisted propulsion), respects all environmental loads acting on a ship at sea (e.g., wind, waves, current), is valid for multiple operational conditions (i.e., speed and draft of the ship), and balances the forces and moments in four degrees of freedom. Validation studies using five example ships (a container ship, a tanker, a cruise ferry, and two RoRo ships) show good agreement of the predicted propulsion power with both model tests in the design condition and full-scale measurements in variable operational conditions. A detailed uncertainty analysis provides an overview of how to further increase the prediction accuracy.

Special focus of the study is put on evaluating measures to decrease the emissions of ships through operational optimization, i.e., speed optimization, alternative propulsion concepts, and new design of zero-emission concepts. ShipCLEAN includes novel methods to evaluate the aerodynamic interaction effects of Flettner rotors on a ship (in between the rotors and between the rotors and the ship), to control the rpm of each rotor in an array on a ship and to evaluate the hydrodynamic forces acting on a ship sailing at a drift angle.

Results from application studies show that fuel savings of around 3% are achievable by optimizing the speed profile of a ship in operation. Wind-assisted propulsion shows the potential to save up to 30% of fuel if applied to a tanker on a Pacific Ocean trade. It is concluded that flexible power prediction models requiring limited input data help to identify and quantify potential fuel savings and to identify motivators for ship owners and operators to apply fuel-saving measures. Further, it is concluded that four degrees of freedom analysis and methods to respect aero- and hydrodynamic interaction effects are crucial to accurately predict the performance of wind-assisted propulsion.

energy efficiency

ship design

speed optimization

energy systems model

performance prediction

wind-assisted propulsion.

Lecture hall EC, EDIT building, Hörsalsvägen 11, Göteborg.
Opponent: Professor Sverre Steen, Department of Marine Technology, NTNU – Norwegian University of Science and Technology, Trondheim, Norway.


Fabian Tillig

Chalmers, Mekanik och maritima vetenskaper, Marin teknik

A generic energy systems model for efficient ship design and operation

Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment,; Vol. 231(2017)p. 649-666

Artikel i vetenskaplig tidskrift

Analysis of uncertainties in the prediction of ships’ fuel consumption – from early design to operation conditions

Ships and Offshore Structures,; Vol. 13(2018)p. 13-24

Artikel i vetenskaplig tidskrift

A 4 DOF simulation model developed for fuel consumption prediction of ships at sea

Ships and Offshore Structures,; Vol. 14(2019)p. S112-S120

Artikel i vetenskaplig tidskrift

Reduced environmental impact of marine transport through speed reduction and wind assisted propulsion

Transportation Research Part D: Transport and Environment,; Vol. 83(2020)

Artikel i vetenskaplig tidskrift

Tillig, F., Ringsberg, J. W. Design, operation and analysis of wind-assisted cargo ships

How much do individual ships contribute to global greenhouse gas emissions?

We know that shipping in total stands for about 2% of the global greenhouse gas emissions. But to answer the question how much each individual ship contributes; we must be able to predict the fuel consumption for each ship in weather conditions the ships are experiencing at sea. Even though ships have been built during several thousand years, it is still challenging to predict the fuel consumption at sea, especially if detailed information of the ship itself are not available, which often is the case for ship owners and operators.

This thesis contributes by developing a simulation model called “ShipCLEAN”, which can predict the fuel consumption of ships in realistic weather conditions. Since the model only requires a handful of ship parameters it is applicable to any ship in service or under design.

How can the greenhouse gas emissions of ships be reduced?

To reduce the fuel consumption and emissions of ships the operation, propulsion and design of ships must be improved. Based on the model “ShipCLEAN”, this thesis presents methods to evaluate the impact of sails installed on ships on the fuel consumption and evaluates the potential of sail-assisted ships on realistic routes. Further, this thesis presents methods to identify measures that can be taken to motivate ship operators to choose lower ship speeds which reduces the fuel consumption and greenhouse gas emissions.

ShipCLEAN - Energieffektivare sjötransporter genom optimering av kopplade transportlogistik- och energisystemanalyser

Energimyndigheten (44454-1), 2017-09-01 -- 2019-12-31.

Energieffektivare sjötransporter genom energisystemanalys av fartyg

Lighthouse, 2014-11-01 -- 2016-12-31.


Hållbar utveckling





Marin teknik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4750



Lecture hall EC, EDIT building, Hörsalsvägen 11, Göteborg.


Opponent: Professor Sverre Steen, Department of Marine Technology, NTNU – Norwegian University of Science and Technology, Trondheim, Norway.

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