Optimal Sizing of BESS Considering Economic Dispatch and VRE in Thailand Generation System

Abstract

The increasing proportion of renewable energy (RE) in a power system causes many problems such as duck curve phenomenon, making its load curve and conventional generator operations change. These issues have become significant concerns. If the difference of the load curve is a huge ramp, the operating costs of the conventional generation will increase. In recent years, the price of battery energy storage system (BESS) has been decreasing continuously. With its fast response characteristic, the BESS is a potential candidate to mitigate the load curve issue. Therefore, this paper proposes an economic dispatch method for minimizing the operating costs of conventional generation integrated with RE generation and the BESS. Besides, the detailed analysis based on Thailand's power generation is provided to achieve the optimal BESS size. According to Power Development Plan (PDP) 2018, the RE generation comprises photovoltaic (PV) and wind generation while the conventional generation consists of combined-cycle and coal thermal generation. The proposed method was performed using the optimization toolbox in MATLAB programming. The amount of RE generation is swept through 10 to 140 percent of its initial value while the amount of conventional generation is constant. The simulation results show that if the RE generation reaches 90 percent, the BESS is required. To obtain the lowest system operating cost, the optimal size of the BESS under the state of charge (SoC) constraint of 50 percent is 3,463.82 MWh. In summary, this proposed method helps deal with the future growth of VRE generation in Thailand's electrical system.