Size and power exchange optimization of a grid-connected diesel generator-photovoltaic-fuel cell hybrid energy system considering reliability, cost and renewability

In this paper, optimal size and power exchange of a grid-connected diesel generator-photovoltaic-fuel cell (diesel/PV/FC) hybrid energy system is investigated by multi-objective optimization for a community in Kerman, Iran. To optimally size hybrid system, number of system components (PV panels, diesel generators, electrolysers, FCs and hydrogen tanks) are considered as decision variables. In this paper, to optimize power exchange between the hybrid system and grid, two other decision variables are introduced: selling coefficient and purchase coefficient. Selling and purchase coefficients are defined to optimize the amount of electricity sold to the grid and the amount of electricity purchased from the grid, respectively. In order to optimally design the hybrid system, multi-objective optimization has been considered with respect to three objectives: levelized cost of energy (LCOE), loss of power supply probability (LPSP) and renewability. Based on simulation results, it can be drawn that when the hybrid system can sell/buy energy to/from the grid, (1) by decreasing non-renewable energy source usage, the value of LPSP increases, (2) by decrease of non-renewable energy usage, value of LCOE increases and (3) using FC system leads to increasing LCOE. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.