Increased energy efficiency through increased port efficiency
The main route discussed for mitigating CO2 emissions from shipping is through increased energy efficiency. Many operational measures that cost-efficiently decrease the energy consumption for shipping companies are available; however, assessments indicate that they have not been fully implemented. Speed reduction due to improved port efficiency has previously been highlighted as a measure with high potential for increased energy efficiency at a low investment cost.
The purpose of this report is to investigate the possibilities to reduce speed at sea when the turnaround time in port is decreased and how this affects the total energy consumption. The research is based on a case study of one short sea bulk shipping company operating in Northern Europe. Quantitative analyses of voyage reports, vessels’ energy consumption curves and Statement of Facts (SoF) for two shipping services were combined with information gained from interviews with onshore managers and operators at the shipping company, ship crew members and managers in ports.
The largest sources of unproductive time in port that could be minimized to improve turnaround time are waiting time due to the ports’ hours of operation, as well as waiting time at berth before loading and discharging due to early arrival. Scenarios have been developed from quantitative and qualitative data in the study that result in 1 to 4 hours of decreased time per port call. With a corresponding speed reduction at sea, the potential for improvement in energy efficiency is 1-5%. This is substantially lower than other assessments found in the literature, but is still impressive. The low investment costs could be confirmed qualitatively, but the transaction costs involved for communication and monitoring between stakeholders could contribute to the slow implementation of this measure.