All hydrogen projects currently being planned or implemented are based on less experience than for the natural gas projects. In addition, there is no fully consolidated technical and regulatory framework. Some countries in Europe are further ahead than others with developing technical and regulatory rules for production, storage, blending with natural gas and transport of hydrogen. In mid and long-term view, the technical and regulatory framework needs to be aligned between the European members in order to maintain an open market and free traffic of natural gas, hydrogen and hydrogen blends all throughout the EU.

In the absence of a not yet fully developed technical and regulatory framework, hydrogen plants and infrastructure need to be engineered anticipating the future technical and regulatory requirements. For the time being, the experience gained in natural gas projects over the past decades will be adopted and applied analogously to hydrogen projects. Specific requirements arise from the potential impact of hydrogen on the integrity of materials for piping, fittings and process equipment, as well as from the quite different physical properties of hydrogen compared to natural gas and other technically relevant gases. This article provides an overview of the challenges related to blending of hydrogen with natural gas.