• 2D-packing with an application to stowage in Roll-on Roll-off liner shipping 

      Hansen, Jone; Hukkelberg, Ivar; Fagerholt, Kjetil; Stålhane, Magnus; Rakke, Jørgen Glomvik (Journal article; Peer reviewed, 2016-08-14)
      Roll-on/Roll-off (RoRo) ships represent the primary source for transporting vehicles and other types of rolling material over long distances. In this paper we focus on operational decisions related to stowage of cargoes ...
    • A Comparison of Single- and Multi-parameter Wave Criteria for Accessing Wind Turbines in Strategic Maintenance and Logistics Models for Offshore Wind Farms 

      Sperstad, Iver Bakken; Halvorsen-Weare, Elin Espeland; Hofmann, Matthias; Nonås, Lars Magne; Stålhane, Magnus; Wu, MingKang (Journal article; Peer reviewed, 2014)
      Different vessel types for transferring technicians for maintenance and inspection of offshore wind farms are often evaluated and compared by their limiting significant wave height for accessing the wind turbines. The ...
    • A metaheuristic solution method for optimizing vessel fleet size and mix for maintenance operations at offshore wind farms under uncertainty 

      Halvorsen-Weare, Elin Espeland; Norstad, Inge; Stålhane, Magnus; Nonås, Lars Magne (Journal article; Peer reviewed, 2017-10)
      Maintenance operations at offshore wind farms are challenging due to the offshore element; maintenance technicians and spare parts need to be transported from an onshore port or offshore station to the individual wind farm ...
    • A Shortest Path Heuristic for Evaluating the Quality of Stowage Plans in Roll-On Roll-Off Liner Shipping 

      Hansen, Jone R.; Fagerholt, Kjetil; Stålhane, Magnus (Journal article; Peer reviewed, 2017-09-27)
      Roll-on Roll-off shipping companies transport rolling cargo, such as cars, trucks and large construction machines. When sailing, this type of cargo must be attached to the deck using chains, to prevent damaging the cargo. ...
    • A variable neighbourhood search heuristic for disruption management in offshore oil and gas logistics 

      Stålhane, Magnus; Albjerk, Nils; Danielsen, Teodor; Krey, Stian; Fagerholt, Kjetil (Journal article; Peer reviewed, 2018-04-18)
      This paper studies operational planning and disruption management in offshore oil and gas logistics. A significant amount of time is currently spent on operational planning, and major costs are caused by disruptions to the ...
    • A vessel pickup and delivery problem from the disruption management in offshore supply vessel operations 

      Albjerk, Nils; Danielsen, Teodor; Krey, Stian; Stålhane, Magnus; Fagerholt, Kjetil (Journal article; Peer reviewed, 2016-06-10)
      This paper considers a vessel pickup and delivery problem that arises in the case of disruptions in the supply vessel logistics in the offshore oil and gas industry. The problem can be modelled as a multi-vehicle pickup ...
    • Operation and Maintenance Modelling 

      Welte, Thomas Michael; Sperstad, Iver Bakken; Halvorsen-Weare, Elin Espeland; Netland, Øyvind; Nonås, Lars Magne; Stålhane, Magnus (Chapter, 2018)
      Operational expenditure (OPEX) is one of the major contributors to the levelized cost of energy (LCoE) for offshore wind farms. To assess different solutions and select the best ones, good models for maintenance and logistics ...
    • Operation and Maintenance Modelling 

      Welte, Thomas Michael; Sperstad, Iver Bakken; Halvorsen-Weare, Elin Espeland; Netland, Øyvind; Nonås, Lars Magne; Stålhane, Magnus (Chapter; Peer reviewed, 2018)
      Operational expenditure (OPEX) is one of the major contributors to the levelized cost of energy (LCoE) for offshore wind farms. To assess different solutions and select the best ones, good models for maintenance and logistics ...
    • Operational planning for routes and schedules for a fleet of fuel supply vessels 

      Christiansen, Marielle; Fagerholt, Kjetil; Rachaniotis, Nikos; Stålhane, Magnus (Journal article; Peer reviewed, 2017-09)
      This paper considers a real operational problem of routing and scheduling a fleet of fuel supply vessels used to service customer ships anchored outside a major port. The problem can be formulated as a rich multi-trip ...
    • Optimizing Jack-up vessel strategies for maintaining offshore wind farms 

      Stålhane, Magnus; Christiansen, Marielle; Kirkeby, Odin; Mikkelsen, Andreas Jebsen (Journal article; Peer reviewed, 2017-10)
      In this paper we present a new two-stage stochastic mathematical programming model that determines the optimal jack-up vessel strategy for an offshore wind farm. Given an offshore wind farm site, and distance to shore the ...
    • Robust planning and disruption management in roll-on roll-off liner shipping 

      Sola Fischer, Andreas; Nokhart, Håkon Stavn; Olsen, Henrik; Fagerholt, Kjetil; Rakke, Jørgen Glomvik; Stålhane, Magnus (Journal article; Peer reviewed, 2016)
      This paper presents different strategies for handling disruptions in fleet deployment in roll-on roll-off liner shipping, which basically consists of assigning a fleet of vessels to predefined voyages at minimum cost. A ...
    • Testing the robustness of optimal access vessel fleet selection for operation and maintenance of offshore wind farms 

      Sperstad, Iver Bakken; Stålhane, Magnus; Dinwoodie, Iain; Endrerud, Ole-Erik Vestøl; Martin, Rebecca; Warner, Ethan (Journal article; Peer reviewed, 2017-11-15)
      Optimising the operation and maintenance (O&M) and logistics strategy of offshore wind farms implies the decision problem of selecting the vessel fleet for O&M. Different strategic decision support tools can be applied to ...
    • The LEANWIND suite of logistics optimisation and full lifecycle simulation models for offshore wind farms 

      McAuliffe, Fiona Devoy; Lynch, Katie; Sperstad, Iver Bakken; Nonås, Lars Magne; Halvorsen-Weare, Elin Espeland; Jones, Dylan; Wall, Graham; Irawan, Chandra; Norstad, Inge; Stålhane, Magnus (Journal article; Peer reviewed, 2018)
      The offshore wind sector has achieved significant cost reductions in recent years. However, there is still work to be done to maintain and surpass these savings across current and future farms. There is increased competition ...
    • The LEANWIND suite of logistics optimisation and full lifecycle simulation models for offshore wind farms 

      McAuliffe, Fiona Devoy; Lynch, Katie; Sperstad, Iver Bakken; Nonås, Lars Magne; Halvorsen-Weare, Elin Espeland; Jones, Dylan; Akbari, Negar; Wall, Graham; Irawan, Chandra; Norstad, Inge; Stålhane, Magnus; Murphy, Jimmy (Journal article; Peer reviewed, 2018)
      The offshore wind sector has achieved significant cost reductions in recent years. However, there is still work to be done to maintain and surpass these savings across current and future farms. There is increased competition ...
    • Vessel Fleet Optimization for Maintenance Operations at Offshore Wind Farms under Uncertainty 

      Stålhane, Magnus; Vefsnmo, Hanne; Halvorsen-Weare, Elin Espeland; Hvattum, Lars Magnus; Nonås, Lars Magne (Journal article; Peer reviewed, 2016-09)
      In this paper we consider the problem of determining the optimal fleet size and mix of vessels to support maintenance activities at offshore wind farms. A two-stage stochastic programming model is proposed where uncertainty ...