Steady-State Optimal Power Flow in Integrated Electricity and Gas Transmission Systems with Hydrogen Injections

Hydrogen is a promising clean energy source for the future energy system. The power-to-gas facilities produce hydrogen from surplus renewable generations, and inject it into the natural gas transmission pipelines for transportation and further use. The operating condition of the Integrated Electricity and Gas Systems (IEGS) should be fully aware and optimized, for restraining the injection of hydrogen within a secure range. This paper proposes a steady-state optimal power flow technique for IEGS with distributed hydrogen injections. First, the IEGS is reformulated in an energy-balanced form considering the impact of hydrogen injection. Then, the steady-state optimal power flow problem is formulated, considering the security constraints of the Wobbe index, the composition of hydrogen, and the Gross Calorific Value at various gas buses. Finally, the proposed technique is validated using IEEE 24-bus RTS and Belgium gas transmission system.