Bi-level capacity optimization model of a wind-photovoltaic-storage energy system considering seasonal hydrogen storage

Addressing the challenge of seasonal power mismatches and severe wind/PV curtailment in hybrid renewable energy systems, this paper designs a wind-photovoltaic-storage energy system considering the seasonal hydrogen storage, aiming to enhance economic efficiency and renewable energy utilization. A bi-level programming model is constructed to capture both the generation-side and dispatch-side dynamics, where the upper-level minimizes the system's investment, operation and maintenance (O&M) costs, and the lower-level minimizes the investment and O&M costs of the dispatch-side equipment considering the power curtailment penalty. Due to the model's nonconvex and nonlinear characteristics, the reformulation and decomposition (R&D) method is adopted to solve the bi-level model iteratively. Case studies demonstrate that seasonal hydrogen storage significantly promotes the consumption of wind and solar power, reducing the power curtailment rate from 38.71 % to 5 %. Scenario analysis further projects that with declining technical costs, the installed capacity of seasonal hydrogen storage will increase by 11.68 % in the deep development phase, gradually displacing some battery storage. This results in a Levelized Cost of Energy (LCOE) of 0.32 CNY/kWh, a Levelized Cost of Hydrogen (LCOH) of 7.87 CNY/kg, and a further decline in the power curtailment rate to 0.23 %, thereby enabling high renewable penetration and improving system economics.