Eoghan Summers, Julia Race, Mohammed Alaa Almoghayer, Dimitri Mignard
Developing transmission pipelines is considered essential to realising renewable hydrogen’s decarbonisation potential in industry, transport, and energy storage. Numerous studies identify pipelines as the most cost-effective option for transporting hydrogen compared with alternative hydrogen carriers and with electricity transmission when hydrogen is the final energy carrier. However, hydrogen’s interaction with steel presents significant technical challenges: it can diffuse into pipeline materials, reducing ductility and fracture toughness and accelerating fatigue crack growth, particularly in high-strength steels at pressures typical in transmission. These risks are exacerbated by pressure cycling arising from variable hydrogen supply. Additionally, hydrogen’s lower volumetric energy density reduces throughput and linepack capacity, complicating system balancing and security of supply. Mitigation strategies include lower-strength steels, pressure limitation, inhibitor gases and coatings, and buffer storage to smooth operating profiles. This review finds current techno-economic studies often omit some challenges and mitigations in cost estimates, indicating a need for more comprehensive modelling.