Cost/benefit analysis of alternative systems for feeding electric energy to ships in port from ashore

The development of maritime transportation has increased the territorial role and the socio-economic relevance of harbors. But, at the same time, it has worsened the environmental impact of the maritime operations on ports and surrounding - often highly inhabited - areas, particularly in the Mediterranean. Since ships at berth need a certain amount of electric energy for hull and hotel services, they must keep their auxiliary engines switched on, inevitably generating exhaust emissions and noise. As a consequence, ports become an important and growing source of pollution and can create relevant risks for the health of the communities living nearby. From the economic point of view, it has been assessed that the costs involved in the shore-side power program can vary widely among ports. In this paper a complete cost benefit analysis will be carried out by keeping into account all costs related to the systems capable of supplying electric energy to ships using systems external to it. In particular, cold ironing, LNG power packs and fuel cells will be evaluated; LNG and fuel cells will be considered both as a fixed source of energy, and as a movable one, when fitted in a barge in order to reach the ship to be powered. Additionally, the results obtained in term of the cost of energy from ashore will be compared with the cost of the energy produced onboard, by keeping into account all charges that compose the real price of the electric energy when using the auxiliary engines onboard ships.