Optimal Scheduling of Integrated Energy System with Hydrogen Considering Gas Flow Dynamics

To increase renewable energy penetration, surplus renewable energy can be used to electrolyze water to produce hydrogen. Hydrogen can be blended with natural gas to facilitate low-cost, large-scale, and long-distance deliveries through the existing natural gas pipelines. To accurately model and schedule the integrated energy system with hydrogen, this paper develops an optimal scheduling approach considering gas flow dynamics. The scheduling problem of the integrated energy system with hydrogen is formulated as a time-domain mixed-integer problem with gas flow dynamics modeled using partial differential equations to guarantee the security of pipelines. The scheduling model also employs binary variables to represent the on/off states of devices, such as electrolyzers. By transforming time-domain partial differential equations into frequency-domain linear equations using a generalized phasor method, the problem is converted into a hybrid time-and-frequency domain mixed-integer linear programming (MILP) problem. The problem can be conveniently solved by commercial solvers and preserves the modeling accuracy of gas flow dynamics and the resulting security of pipelines. Numerical testing results demonstrate the modeling accuracy and computational efficiency of the proposed approach.