关键词: 用户侧, 电化学储能, 移峰填谷, 经济性评估

Abstract:

To mitigate the peak-valley difference in electricity load, the application of user-side electrochemical energy storage systems (EESS) has become increasingly widespread. Consequently, the evaluation and optimization of the expected economic performance of such user-side energy storage systems hold significant importance. Based on the daily average electricity load data of a building in a certain unit, this study takes the electrochemical energy storage system as the research object. It considers cost and revenue items, including system installation costs, maintenance costs, peak-shaving and valley-filling benefits, and reduced demand charge. Meanwhile, it also takes into account the social benefits brought by the system's stable operation to the power grid, and establishes a bi-level programming mathematical model for economic evaluation. The outer-level programming model is used to optimize the configuration parameters of the energy storage system, while the inner-level model is designed to optimize the system's operating parameters. This dual-level approach aims to achieve both the optimal economy of the battery energy storage system (BESS) throughout its project lifecycle and the minimum standard deviation of the user's equivalent load.In accordance with the aforementioned mathematical model, this study developed a corresponding economic evaluation software using Python. The software comprises a GUI input module, a data loading module, an outer-level optimizer, an inner-level optimizer, and a result visualization module. The SLSQP algorithm was employed to optimize the system's rated configuration and operating status, thereby obtaining the optimal configuration of the energy storage system that maximizes the benefit-cost ratio. This configuration serves as a guide for users to select appropriate rated power and rated capacity of energy storage equipment. Furthermore, taking a lithium iron phosphate battery energy storage system as an example, this study illustrates the usage of the evaluation software. It outputs the optimal rated power, optimal rated capacity, typical daily operating load curve, and charge-discharge state curve. Additionally, a comparative analysis is conducted on the changes in electricity load before and after the installation of the energy storage system.

Key words: User-side, Electrochemical energy storage, Peak-valley arbitrage, Economic evaluation