Hydrogen blending in natural gas network

Hydrogen blending is the injection of certain amounts of hydrogen into a natural gas stream using existing natural gas infrastructure. Studies indicate that integrating blended hydrogen into the gas networks is feasible at levels of around 5-10 v% (volumetric share) with relatively minor upgrading, while in distribution networks, with polymer-based pipelines, shares of up to 20% would not require significant changes in the infrastructure, although the gas chromatographs should at least be adapted. While a 20% threshold will require some infrastructure upgrading, such as retrofitting the compressors, it seems to be the technical upper limit above which significant investments may be needed, in particular for some downstream installations and end-use equipment, although higher concentrations could be reached through R&D.