Towards net-zero maritime port microgrids: the case study of the Heraklion port

This article explores energy storage as a solution to the challenges of viable energy transition, particularly due to high peak demand requirements. Focusing on the Greek legislative framework, the study examines net-zero solutions under both net metering and zero feed-in scenarios. Historical data analysis using Fourier transform provided insights for long-term investment forecasting. The Moth-Flame Optimizer (MFO) algorithm was employed to optimise the technical requirements of photovoltaic (PV) systems and battery storage for net metering. For the zero feed-in scenario, optimisation included electricity production of sized PV capacity and Proton-Exchange Membrane (PEM) fuel cells, hydrogen production through PEM electrolysers, and hydrogen storage systems. The Port of Heraklion, a seaport microgrid with limited grid capacity and space, was selected as the case study. The study evaluated the optimal Net Present Value (NPV) of each investment scenario, constrained by installation area limits. The results demonstrated the superiority of the MFO over the Generalised Reduced Gradient (GRG) method. For a 20-year investment, the optimal NPV was 11.64 million EUR with 4.41% area usage in the net metering scenario, while the zero feed-in scenario predicted a present value profit of 1.18 billion EUR, requiring 29.84% of the available area.