By investigating a short sea bulk shipping company, Hannes Johnson, Chalmers University of Technology, and Linda Styhre, IVL Swedish Environmental Research Institute, found that during a year, the ships spent roughly half of their time in port, and half of that time was not productive. The two most important reasons for why ships were stuck at port instead of transporting goods were ships early arrivals to ports and the ports opening hours. Ports are often closed during the nights and weekends and if ships entered the port they often had to wait due to a closed port or because of other ships. Hence, ports were not ready for the ship and the stevedores could therefore not unload or load the vessel.
There might be several aspects that hinder the development of reduced time in ports. Operators feared that they might be late to the port, something that could be costly or involve missed transport assignments. The communication between ship, shore and port is often not analysed and used in order to improve the situation. Lack of knowledge concerning the relationship between energy use and speed were also found as a reason for why ships did not use optimal speed. Increasing open hours was also contractually complicated.
If the above obstacles could be solved, there is much to gain - both for the society and for shipping companies. The research by Hannes Johnson and Linda Styhre indicates that ships that reduce its time in port with only 1-4 hours decrease its energy use with 2– 8%. Shipping companies could reduce their environmental impact and save on energy costs by reducing speed and arriving just in time to the port. However, in beneficial market conditions a shipping company could also use the extra time to take more cargo per year.
Linda Styhre and Hannes Johnson will continue working with energy efficient shipping at IVL Swedish Environmental Research Institute and Chalmers through a project financed by the Swedish Energy Agency.