Repair Today, Repurpose Tomorrow: EPRS Readiness for Hydrogen Pipelines
Authors: Rutger Schouten, Burhan uddin Hussaini
Abstract
As offshore operators prepare to repurpose natural gas pipelines for hydrogen or carbon dioxide (CO₂) transport, critical questions arise about the long-term performance of existing repair methods. Conventional welded and mechanical repairs, developed for natural gas systems, may not perform reliably under the distinct physical and chemical conditions presented by hydrogen, particularly in subsea environments.
This research was initiated in response to an operator’s request to assess the implications of performing a repair today using mechanical or welded techniques on a 36-inch subsea natural gas pipeline, with the expectation that the asset may later be repurposed for hydrogen service. The study evaluated how such repairs, implemented under current conditions, would perform in future hydrogen environments and further explored the broader implications for Emergency Pipeline Repair Systems (EPRS).
To support the analysis, a representative damage case anchor impact on a hydrogen-filled 36-inch pipeline that had previously undergone repair during natural gas service was modelled. This scenario was selected to evaluate the structural and sealing performance of the repair under realistic mechanical loading and hydrogen-specific conditions. The assessment covered the full EPRS lifecycle, including damage detection, isolation, decommissioning, repair, and recommissioning. Special attention was given to hydrogen’s high diffusivity, elevated pressures, leak potential, and material sensitivity to embrittlement and fatigue.
The findings highlight the need for hydrogen-compatible repair strategies and EPRS planning that account for legacy repairs and hydrogen’s unique behaviour. Insights from operators, technology vendors, and materials experts informed practical and technically grounded conclusions. The paper proposes an integrated, forward-looking EPRS approach to support safe, reliable operation of aging pipeline assets during the transition to low-carbon energy systems.