f Hydrogen Impact on Pipeline Cathodic Protection Performance and External Coating Degradation

National Grid Gas Transmission (NGGT) contracted Rosen UK Ltd (Rosen) and The University of Warwick UK (Warwick) to conduct a literature review on the subject of “impact of hydrogen conveyance on the performance of cathodic protection (CP) and pipeline coating degradation”. NGGT’s motivation for this project comes as part of the route to Net Zero, with NGGT looking at opportunities to increase the percentage of hydrogen transported within natural gas. As the percentage of hydrogen increases there may be increased risk for the evolution of atomic hydrogen, which could permeate through the steel pipe and affect external coatings and the efficacy of CP polarization potentials. Pertaining to the above, NGGT’s goal is to gain an appreciation of the work that has been undertaken on coatings and CP systems of hydrogen pipelines, and what corrosion protection currently utilized on hydrogen pipelines worldwide as well as reported effects of hydrogen on the behaviour of coating
types with or without impressed voltage. Specifically, the focus was to identify potential impacts of hydrogen on coating performance adhesion and CP polarization for differing concentration levels of hydrogen being transported at a range of pressures for:
1. A selection of applied and factory coatings and coating types both for a range of aged and new applications.
2. A selection of coating holiday (coating defect) sizes at varying levels of CP polarization.
The project was divided into three work packages:
1. Work Package 1: Literature Review – Rosen as an Industrial Partner.
2. Work Package 2: Literature Review – Warwick as an Academic Partner.
3. Work Package 3: Reporting – presented as a joint effort between Rosen and Warwick.
During the execution of the projects, all parties involved participated in two interactive on-line workshops; Workshop 1 was held on the 20th of December 2022 and Workshop 2 on the 2nd of May 2023. Both workshops served as platforms for sharing work progress and obtained results, and their discussion; presentation slides delivered at both workshops can be found in Appendix A – Workshop 1 Presentations and Appendix B – Workshop 2 Presentation.
The current document presents the final stage of the project, i.e. Work Package 3.
This report was submitted to HSE for their assessment of the safety evidence for 100% hydrogen heating, which can be found at Hydrogen heating: HSE assessment of the safety evidence - GOV.UK.
Queries should be directed to DESNZ: https://www.gov.uk/guidance/contact-desnz.