Cold ironing and onshore generation for airborne emission reductions in ports

Cold ironing (or onshore power supply) addresses airborne emissions while ships are berthed in port. By providing the electrical power demands from shoreside electricity, the onboard auxiliary generators can be switched off for a locally emission-free solution. The net emissions will of course be dependent on the actual shoreside electricity mix, but reductions can be realised in most cases. This study looks at the various electrical configurations available for cold ironing of berthed vessels. Shoreside generation using liquefied natural gas as an alternative fuel is also considered as a complement to cold ironing. This provides the possibility of hybridised solutions combining power supply from the grid or from clean, onsite generators. Using real data from an operational European port, the various cold ironing configurations are modelled and optimal trade-off solutions were identified. This is achieved by considering the reduction in emissions and minimisation of component costs as a multi-objective non-linear optimisation problem. The results show that CO₂ emissions can be reduced by up to 40% by using cold ironing, while the use of liquefied natural gas shore generation can reduce the sulphur and particulate emissions in port to extremely low levels.