Energy efficient port calls - A study of Swedish shipping with international outlooks

The calculation of the total fuel consumption of Swedish shipping in 2014 resulted in approximately 1 500 000 tonnes of fuel. Significantly more fuel is used at sea than in the port areas. In Sweden, the high-frequency shipping services contribute to a significant amount of the total fuel consumption: the ships that call more than 100 times/year stand for about 19 percent of the total consumption while ships with less than 10 calls contributed to 38 percent.

Fuel consumption and CO2-equivalent emissions for ships in three Swedish ports and three foreign ports are presented and discussed, see table below. Comparisons between the ports can be made only in a context of ship traffic characteristics, e.g. ship types, ship sizes and call frequency. Further, the geographical boundaries of the inventory affect the result. The average CO2- equivalents per port call reveal great differences between the ports. Port of Long Beach and Port of Sydney have a high ratio of large ships, which partly explain the high average values. Large ships have larger installed main engines and auxiliary engines, and stay a longer time at berth for the loading and unloading of cargo. More than half of the emissions from ships in ports originate from the time at berth.

International shipping contributes to approximately 2.4 percent of greenhouse gas (GHG) emissions, and its share is expected to increase in the future. This stands in contrast to ambitions to reduce the use of fossil fuels. In order to reach sustainability objectives international steps towards more strict policies and regulations are necessary for the shipping sector. National efforts are in many ways limited to voluntary incentive schemes, and local port initiatives cannot significantly influence overall energy needs and emission levels. However, it is argued that an individual port can still facilitate a transfer to more energy efficient shipping and a reduction of emissions from ships in the port areas. For example, ports can implement environmentally differentiated port dues and give rebates to ship owners that perform well, manage and administer the supply of alternative fuels and on-shore power connections, and work for a reduction of ship speed in the fairway channel. The call frequency of individual ships to the same port is of high relevance to the improvement potential. The diverse conditions between ports suggest that emission abatement measures need to be customer-tailored for specific ports.