The EPLANopt model for Favignana island's energy transition

Energy costs, carbon dioxide emissions, security of supply and system stability are common challenges in small islands all over the world. The European Union identified islands as perfect sites to implement innovative solutions to boost the energy transition towards a sustainable, independent, secure and low carbon energy system. In this framework, energy planning is an indispensable tool to optimally design the future energy system selecting proper renewable energy sources as well as the optimal flexibility strategies such as electric energy storage or sector coupling solutions. Energy system modelling represents one of the most used method for energy planning; indeed, energy models enable to simulate the real energy system functioning as well as its operation costs. Nevertheless, not many researches using multi-objective optimisation have been applied to insular case studies. In this paper, the EPLANopt model is applied to the case study of the Favignana Island in order to investigate the optimal configurations of the island energy system in 2050 with a multi-objective analysis. In order to appropriately analyse the case study of a non-interconnected island, an additional constraint is analysed to preliminary consider the system stability. The model is used to evaluate different energy mix, based on high penetration of renewables, considering several solutions for handling the excess electricity production (namely, electricity energy storage, power to heat and power to transport solutions) and to improve the overall energy efficiency (i.e. solar collectors and heat pumps). Results show that sector coupling solutions would lead to much greater impact in terms of carbon avoidance and economic savings managing the non-dispatchable renewable generation and maintaining the critical excess electricity production within feasible values. Results show that Favignana should indeed bet on photovoltaic and if vehicle-to-grid strategies are largely adopted the need for electricity storages is strongly reduced.