Liner Ship Scheduling Problem Considering The Optimization Of Sulphur Emission Control Area Widths

Water transportation brings huge profits,but also brings pollution problems.Emissions from ships,including sulphur dioxide and carbon dioxide,have a negative impact on human health and the marine environment.In order to reduce sulfur emissions from ships,the International Maritime Organization has set up four Sulphur Emission Control Areas(SECAs),and requires ships sailing within SECAs to use low-sulfur ship fuel with sulfur content of no more than 0.1%.Different countries or regions set up different SECAs with different structures,especially for various SECA widths.It has become an important research issue on how to determine the optimal SECA width.For this purpose,this paper investigates the liner ship scheduling problem considering the optimization of SECA widths,for the perspective of government and liner shipping companies.Our studied problem can be regarded as a network design problem for determining the optimal SECA width.By considering two research scenarios,i.e.,a single ship route and liner shipping networks,this paper proposes two bi-level programming models.The upper level model aims to determine the optimal SECA width,in order to minimize ship sulphur emissions and ship carbon emissions as dual objectives.The lower level model addresses a joint optimization of sailing paths,fleet deployment,ship speeds and container routing,in order to minimize the total operating cost,for two research scenarios,respectively.The lower level problem is formulated as a mixed-integer linear programming model.By enumerating all possible values of the SECA widths,the bi-level programming model can be reduced to the lower level model,which can be solved by CPLEX.In numerical experiments,a realistic ship route and a realistic liner shipping network are considered.Numerical results show that,with increase of the SECA width,the ship speed within SECAs decreases,the number of ships deployed increases,the total cost increases,and ships prefer the sailing path with the shortest sailing distance.When the SECA width is between 12 and 200 nautical miles,ship sulphur emissions and ship carbon emissions can be balanced to some extent.It is not proper to reduce carbon emissions if the SECA width is too large.