Hydrogen blending to existing natural gas networks is considered a reasonable intermediate step for achieving carbon neutrality and for enhancing the hydrogen economy. Methane-hydrogen gas blends exhibit physical properties and combustion characteristics that are different from their constituents. These property differences influence the flow behavior and the energy transport efficiency in pipeline transportation. A computational fluid dynamic modeling framework was developed to quantify frictional losses and energy efficiency of transport of methane-hydrogen blends across representative sections of a large gas network.

The principal conclusions from the present study are:

1. The increase in the energy required for transporting hydrogen as methane-hydrogen blends depends on the volume fraction of hydrogen, the nature of the flow conditions, pipe diameter, pipe roughness and pipe bends.

2. Pipelines that have larger surface roughness or smaller diameters or those with bend sections require greater energy for transporting gas blends.

3. The methane-hydrogen gas blends develop a core-annular flow pattern under steady state conditions with the denser and more viscous methane flowing near the pipe wall as the annulus while the less dense and less viscous hydrogen concentrated more towards the mid-sections of the pipelines.