Size optimization of new hybrid stand-alone renewable energy system considering a reliability index

Over last two decades, solar and wind energies have become an alternative to traditional energy sources. These alternative energy sources are non-polluting, free in their availability and are renewable. Another alternative is tidal energy, which is related to falling and rising ocean water levels. Tidal behavior can be predicted easily and this means that if it is enabling to harness tidal energy, it can be produced power for specific periods of time. In this paper, a new hybrid combination of renewable energy sources is considered. The combination of wind, photovoltaic and tidal is taken into account as a primary and battery as an auxiliary source. The aim of design is to minimize the annualized cost of the generation system over its 20 years of operation. Determining the capacity of hybrid wind, photovoltaic, tidal and battery is formulated as an optimization problem. The objective function is the minimization of the cost with the constrain having specific reliability index. To evaluate the system reliability level, the Equivalent Loss Factor (ELF) has been used as an index. Comparison between hybrid wind, solar and battery and new combination of renewable energy is done and it is shown that the combination of wind, solar, tidal and battery is more economical. Particle Swarm Optimization (PSO) is used for optimal sizing the system. Simulation results are carried out by MATLAB software. It is shown that hybrid system is the best configuration that has minimum cost and can satisfy all constrains.