Optimization of the capacity configuration of an abandoned mine pumped storage/wind/photovoltaic integrated system

Constructing a new power system with renewable energy as the main component is an important measure for coping with extreme weather and maintaining the stability and efficiency of the power system; in particular, pumped storage is an effective means of smoothing fluctuations in the wind and photovoltaic power output. Therefore, considering the reutilization of abandoned mines, this paper constructs an integrated abandoned mine pumped storage/wind power/photovoltaic system. By establishing the mathematical model and capacity configuration model of the system, an analysis of wind/photovoltaic output characteristics is carried out. A nondominated sorting genetic algorithm is used to solve the optimisation problem, with the goals of maximizing the power supply guarantee rate and new energy absorption rate and minimizing the levelized cost of energy. On this basis, a grid power transmission channel optimization strategy is established to ensure that power transmission to the grid is maximized. The monthly power supply guarantee rate and monthly new energy absorption rate in the configuration results are compared and analysed, and the sensitivity of wind power, optical power, initial investment cost, and effective on-grid power to the levelized cost of electricity is considered. Then, by combining the abandoned mine data, eight different sets of parameters of pumped storage are selected for the optimal configuration study, and the factors influencing the pumped storage regulation capacity are studied. Finally, based on the original three objective functions, the storage equivalent utilization rate, system complementarity, power generation revenue, new energy access rate and new energy utilization rate are added to the analysis, and the hierarchical analysis method combined with fuzzy comprehensive evaluation is used to evaluate the comprehensive benefits of pumped storage with nine different parameters. The optimized capacity configuration of the standard pumped storage of 1200 MW results in a levelized cost of energy of 0.2344 CYN/ kWh under the condition that the guaranteed power supply rate and the new energy absorption rate are both >90%, and the study on the factors influencing the regulating capacity of pumped storage concludes that the rated head, the adjustable reservoir capacity and the installed capacity of the pumped storage are positively correlated with its regulating capacity. Through comprehensive benefit evaluation, it is concludes that pumped storage type 5 provides the greatest comprehensive benefit. This study provides valuable reference information for reducing the impact of renewable energy on the power grid and realizing the reuse of abandoned mines.