Benchmarks and measures for better fuel efficiency.

Abstract

Shipping will face an escalating competition in the future, as more stringent environmental regulations will lead to significant higher fuel costs. Today, the cost of fuel stands for approximate 35-70% of total operational cost. Fuel efficiency measures are vital in order to stay competitive in the future. The issue with the study is to examine how AIS data can be used to compare ships against each other with appropriate benchmarks in order to identify measures for better fuel efficiency. A case study of 44 general cargo ships was carried out with AIS data from 2010-2011. These were two sister groups of 7 700 dwt and 12 700 dwt, with 22 ships in each group. Each group of sister ships were selected from their design and configuration in order to eliminate any design configuration differences in the operational analysis. Disturbance in AIS data was corrected and only voyages with coherent data without time gaps were used in analysis. Ships in study show on a significant potential of improvement in terms of fuel efficiency. Short periods at high speed increase the average fuel consumption in total. All ships were operated at a significant higher average speed than the best economic speed, i.e. lowest cost per nautical mile. There were also tendencies of differences between the operators, where some operators tend to run their ships at a more fuel-efficient way than others. Capacity utilization analysis indicated a spare of 10-20% before hitting the optimum span, which show that fuel efficiency can be improved by increasing the output of the ships i.e. more cargo. However, the most important fuel efficiency measure is speed reduction, i.e. slow steam. The theoretical no anchoring strategy calculations confirm that there are great possibilities to minimize anchoring time in favour of speed reduction.