Optimal sizing of a photovoltaic/energy storage/cold ironing system: Life Cycle cost approach and environmental analysis

Traditional cold ironing allows ships to shut down their auxiliary engines, during the berthing time, and to be powered by an on-shore power supply. Traditionally the energy demand is satisfied by electricity form the national grid. Alternatively, a local energy production increases the energetic self-sufficiency of the port areas and reduces the pressure on the national grid with continuous peaks of energy demand. This way the port area can be considered a microgrid, characterized by both energy producers and consumers. This paper presents an optimization model, implemented on MATLAB, to provide the best sizing for a combined photovoltaic/energy storage/cold ironing system. The ferry traffic of the port of Ancona (Italy) has been taken as case study. The proposed model returns the percentage of the energy demand covered, the interactions with the national grid, and the optimal size of the PV plant and the storage capacity basing on a Life Cycle Cost (LCC) approach. Results show that the optimal configurations are 2100 kW and 3600 kW with 5750 kWh (without and with storage system) considering lower initial and operational costs, and 3700 kW and 6400 kW with 17,350 kWh (without and with storage system) hypothesizing higher costs. All scenarios ensure an environmental saving, compared to traditional on-board diesel generators, with 87.4 % maximal CO2 reduction achieved.