Polygeneration systems for ports based on renewable energies: dynamic simulation and case study

The increasing energy demand in harbour areas, coupled with the need to reduce pollutant emissions, has led to the development of renewable energy-based polygeneration systems to face the carbon footprint of ports and ships at berth. In this way, ports can be converted into modern energy hubs in the coming years. From this point of view, this paper presents a new dynamic simulation model for assessing and optimizing the energy and economic impact of ports. Here, systems and renewable energy sources can be designed to be connected to national electricity and natural gas grids and can include also hydrogen and thermal energy networks, as well as different biomass fluxes (to be exploited for energy aims). Energy availability/demands of near towns and port buildings/infrastructures are included in the dynamic assessments. On-shore power supply is also modelled. Hourly weather data and different prices for all the considered energy carriers are taken into account hour by hour. A multi-objective optimization approach is also implemented in the model adopting energy and economic indexes to be optimised. The whole model is implemented in a computer tool written in MATLAB. For showing the capability of the developed model, a novel case study referred to the port of Naples (South-Italy) is presented. Here, several renewable energy sources are considered together with electricity integrations by the national grid. In the conducted analysis, optimization targets are the maximization of system self-consumption and self-sufficiency as well as the minimum simple payback period. Results show that very high rate of renewable energy produced on-site can be exploited (up to 79%) by the considered port facilities, ensuring increasing independency from utility power grid (self-sufficiency index up to 40%).