Optimal coordination of electricity-P2G-gas system to facilitate renewable energy integration

Abstract

This paper proposes a novel optimal operation strategy for the integrated electricity and natural gas systems (IEGSs), considering an improved Power-to-Gas (P2G) model to characterize the detailed process from renewable energy to methane. Compared with the existing operation strategies that use a simple constant to model the conversion energy efficiency, this paper develops a detailed P2G model considering both electrode kinetics and thermal dynamics of the electrolyzer. It elucidates the interaction between the P2G and the flexibility of multi-energy systems, facilitating the adaptation of the electrolyzer to various operating scenarios. First, the proposed approach employs a step curve fitting to obtain the temperature-dependent current-voltage model and applies the Forward Euler method to obtain the discretized thermal model of the electrolyzer. Then, a multi-period optimization problem incorporating DC power flow and steady-state optimal gas flow, together with the embedded P2G model is formulated. Finally, three cases on the PJM 5-bus power system connected with a 7-node natural gas system validate the effectiveness of the proposed strategy.