Day-Ahead Scheduling of Offshore Wind-Hydrogen Systems Coupling Non-linear Electrolyzer Characteristics and Gas Network Dynamics

Abstract

To address the requirements of large-scale renewable energy integration and cost-effective hydrogen transmission, this work proposes a dayahead coordinated optimal scheduling strategy for an offshore wind-hydrogen coupled system. Conventional scheduling paradigms typically simplify electrolyzer efficiency and pipeline transportation capacity into linear models, thereby neglecting the operational safety risks associated with hydrogen-in-oxygen (HTO) cross-permeation under partial-load conditions and dynamic pipeline pressure fluctuations induced by long-distance hydrogen transmission. To bridge these gaps, an electro-thermal-hydrogen coupling model for the alkaline (ALK) electrolyzer was established accounting for the dynamic lower-bound constraint dictated by the HTO impurity safety threshold. Subsequently, the non-linear relationship between flow rate and flow drop in both the low-pressure gathering and high-pressure transmission networks is transiently modeled via the Weymouth equation, thereby effectively capturing the spatio-temporal dynamic coupling within the power-to-hydrogen and transmission processes. On this basis, a multivariate non-linear programming dayahead scheduling framework is formulated to maximize the comprehensive revenue of the offshore wind-hydrogen coupled system while fully exploiting the dual regulatory potentials of both the electrical and hydrogen domains. Simulation results demonstrate that the proposed model effectively guarantees the secure operation of the system and fully leverages the inherent “line-pack” energy storage elasticity of the pipeline network within allowable gas pressure thresholds. Furthermore, when subjected to wind power forecasting errors and load fluctuations, the wind-hydrogen stations exhibit self-balancing capabilities and achieve peak-shaving and valley-filling for the receiving grid in response to electricity prices, thereby revealing outstanding operational flexibility.