A Study on Ancillary Services Charges for Microgrids in Thailand

This study highlights the importance of imposing Ancillary Service (AS) charges on microgrid systems. Ancillary services, including frequency regulation, voltage regulation, reserve power, and black start, are critical for efficient microgrid operations. Currently, in Thailand, no AS charges are collected from microgrid users, resulting in the electricity authority shouldering the costs of these services. Therefore, it is essential for the electricity authority to implement AS charges to distribute these costs among microgrid users, as the services benefit all users within the power system. This study proposes a systematic framework for AS calculations, utilizing the Long-run Average Incremental cost (LRAIC) method. The methodology involves cost allocation based on incremental interment and operations expenses within the generation system. The AS charge calculation considers key parameters, including frequency repones simulation data from DIgSILENT, reserve margin requirements, installed capacity, and cost structures associated with AS provision in the generation system. The computational results indicate that the cost share attributable to AS is approximately 12.7% of the overall generation system costs, aligning with previous studies [9], which estimate AS costs between 5% to 25% of total generation and transmission system costs. Additionally, the microgrid system, contingent upon AS procurement from the main grid, incurs an annual service fee of 81,905.45 THB. The findings of this study contribute to developing regulatory policies that ensure transparent and equitable cost allocation for AS service. Additionally, the proposed framework lays the foundation for establishing an AS market in the future, promoting market- driven efficiency and incentivizing new AS providers.