Modeling and analysis of linepack and linedraft in hydrogen-blended natural gas pipelines

Integration of hydrogen into existing natural gas infrastructure is gaining traction to decarbonize energy systems while utilizing the established pipeline networks. Hydrogen blending significantly impacts pipeline storage dynamics, influencing its linepack capacity, pressure regulation, and energy delivery performance. To this end this study investigates the transient behavior of transporting hydrogen and natural gas blends (0–20 %) through high-pressure pipelines under packing and drafting conditions. The results indicate that hydrogen blending reduces linepacking time, enabling quicker pipeline responsiveness but poses challenges such as increased outlet pressure and accelerated pressure drops during drafting. At lower pressures (<8.5 MPa), linepacking times are significantly longer compared to higher pressures (>8.5 MPa), highlighting the pressure management within the linepack flexibility and storage optimization. Drafting scenarios demonstrate decrease in linedraft time from 2.5 h to 2 h. Additionally, hydrogen blending increases linepack volume but decreases linepack energy by approximately 10 %. This dual effect presents a trade-off between increased storage volume and decreased energy delivery efficiency, with significant implications for system operation and planning.