Hydrogen Blending in Natural Gas Pipelines: A Comprehensive Review of Material Compatibility and Safety Considerations

The increasing demand for energy and the urgent need to reduce carbon emissions have positioned hydrogen as a promising alternative. This review paper explores the potential of hydrogen blending in natural gas pipelines, focusing on the compatibility of pipeline materials and the associated safety challenges. Hydrogen blending can significantly reduce carbon emissions from homes and industries, as demonstrated by various projects in Canada and globally. However, the introduction of hydrogen into natural gas pipelines poses risks such as hydrogenassisted materials degradation, which can compromise the integrity of pipeline materials. This study reviews the effects of hydrogen on the mechanical properties of both vintage and modern pipeline steels, cast iron, copper, aluminum, stainless steel, as well as plastics, elastomers, and odorants that compose an active natural gas pipeline network. The review highlights the need for updated codes and standards to ensure safe operation and discusses the implications of hydrogen on material selection, design, and safety considerations. Overall, this manuscript aims to provide a comprehensive resource on the current state of pipeline materials in the context of hydrogen blending, emphasizing the importance of further research to address the gaps in current knowledge and to develop robust guidelines for the integration of hydrogen into existing natural gas infrastructure.