Abstract:
The portion of renewable energy (RE) increases because RE generation has no fuel cost and is clean energy. In Thailands generation system, fossil fuel is a primary energy source, which will be expensive and insufficient in the future. Thus, the variable renewable energy (VRE) generation, i.e., solar and wind, becomes an attractive source of generating electricity. However, the increasing proportion of VRE generation in a power system changes load curve and conventional generator operations since they are unpredictable and uncontrolled. As a result, this issue can be solved by using battery energy storage systems (BESSs). The BESS improves power system flexibility and reliability Moreover, its price has been decreasing continuously. This research proposes a method to determine the optimal BESS size which can balance load and conventional generation when VRE generation increases. Meanwhile, the old generator dispatch instructions provided by Electricity Generating Authority of Thailand (EGAT) were used. The proposed method uses an economic dispatch for minimizing the operating costs of generation and calculating the capital cost of the BESS with the VRE generation. This thesis considers the increase of VRE generation in each case study. The analysis considered electrical demand and generation data in Thailands system. The result shows that if the VRE generation reaches 90 percent, the BESS is required. The optimal BESS operates with the conventional generation, which obtains the minimum operating cost, and the capital cost of BESS is considered.