Speed optimization with route improvements

In liner shipping the increased focus on emissions and the low freight rates of maritime container freight increases the focus on green cost reduction measures. Clearly reducing fuel consumption also reduces the emissions resulting in a win-win situation. Methods for speed optimization reducing bunker consumption for a given path has previously been developed and applied to predetermined routes where the transit times of demand is ensured.

In this paper we will combine the speed optimization with a local search method for optimizing the port call order thus arriving at a even lower bunker consumption. Clearly when changing the routes some demands may be discarded due to transit time penalties or rerouted with a delay penalty. Moreover in the speed optimizer we consider the possibility of allowing for longer round trip time, slow steaming, at the cost of inserting vessels where the transit time of the demand is required to be satisfied or otherwise penalized.

Preliminary results are presented for a real-life size liner shipping network.