Funded via Ofgem’s Network Innovation Allowance, the project will assess whether oxygen can act as a practical inhibitor to embrittlement.

Penspen will also analyse alternative gas inhibitors, delivery mechanisms, and the design requirements for an oxygen dosing system suitable for National Gas’ planned hydrogen network.

The company’s Innovation Engineer, Robert Best, explained that inhibitors could allow hydrogen pipelines to operate at higher pressures with greater pressure flexibility. This could improve throughput, asset utilisation, and overall network efficiency.

“However, significant challenges remain with regard to the implementation of this technology,” Best added.

The British transmission system operator is developing a 1,500-mile hydrogen transmission system, comprised of repurposed natural gas pipelines and a new hydrogen network.

However, hydrogen embrittlement remains a key technical challenge, as prolonged exposure degrades steel toughness and ductility while accelerating fatigue crack growth, limiting operating pressures and cycling.

“With our experience supporting operators with hydrogen infrastructure projects, mechanical testing programs, and process equipment design, Penspen is uniquely placed to support National Gas with this innovative project,” explained Dominic Wynne.

Penspen’s Regional Business Development Manager added, “The results will play a critical role in defining an optimised operating window in both new and repurposed pipelines, supporting the transition to low-carbon energy.”

CEO Peter O’Sullivan recently told H2 View that converting steel transmission pipelines is the most challenging part of the hydrogen transition.

O’Sullivan noted that even small amounts of hydrogen can reduce fracture toughness and fatigue life.