### Multiobjective Optimization of PV-Bat-SOFC Hybrid System: Effect of Different Fuels Used in Solid Oxide Fuel Cell

Abstract

The purpose of this study is the multiobjective optimization of the combination of photovoltaic (PV) panels, batteries (BAT), and
a solid oxide fuel cell (SOFC) according to different fuels for solid oxide fuel cell. The most desirable hybrid system is the one
that has the least cost, the least emission, and the most reliability. But, these objectives are in conflict with each other. In
order to obtain the optimum solutions (solutions are different in the number of PV panels, the number of batteries, and the power
of SOFC), a multiobjective optimization evolutionary algorithm [Pareto envelope-based selection algorithm (PESA)] is used. This work
compares using different fuels as SOFC fuel in the hybrid system. Results have been compared to specify the more favorable fuels for
SOFC economically and ecologically. Optimization is done for two categories of fuel price: international fuel prices and Iran fuel
prices. Moreover, the sensitivity analysis of fuel price is considered. The effect of change in SOFC power is examined to determine
enough auxiliary power for this hybrid system. If the angle of panel can change monthly, PV panel productivity increases and the
required SOFC power decreases, therefore the annualized cost and emission are reduced. In the present work, the effect of the monthly
change of the panel angle is considered. Results show that the most appropriate fuel for SOFC in the hybrid system is natural gas.
It causes low annualized cost (ANC) and low CO2 emission. If the panel angle changes monthly, the solar energy utilization efficiency
increases and panels produce more power and the hybrid system provides better economical and ecological conditions.