A Day-Ahead Economic Dispatch Optimization Model of Integrated Electricity-Natural Gas System Considering Hydrogen-Gas Energy Storage System in Microgrid

Abstract

In background of rapidly increasing penetration of renewable energy, it is of economic and environmental importance to construct integrated electricity-natural gas system. Simulation process of power-to-gas (P2G) in traditional integrated electricity-natural gas system model is excessively simplified, where environmental benefits is not adequately considered. This paper, for the integrated electricity-natural gas system, proposed a P2G implementation system with an intermediate buffer called hydrogen-gas energy storage system (HGESS). In HGESS, P2G process is subdivided into processes of power-to-hydrogen and power-to-gas, forming an efficient electric-gas-electric energy closed-loop flow model with fuel cells and an electric-gas-electric energy closed-loop flow model with micro turbine respectively in two phases. Then, combining HGESS and micro network, a model of day-ahead optimal economic dispatching considering energy conversion loss during P2G process and environment cost is proposed. Piecewise linearization and the second order conic relaxation are used to linearize the nonlinear boundary of power flow and natural gas flow in the solution algorithm. At last, two kinds of scenarios with high and low wind power penetration are adopted in numerical case study, and results show that HGESS in integrated electricity-natural gas system under both high and low wind power penetration has productive economic and environmental benefits, and will have wide application prospect in future.