Transmission, Distribution & Storage
Hydrogen Impact on Pipeline Cathodic Protection Performance and External Coating Degradation
Mar 2026
Publication
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.
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.
HyNTS Pipeline Dataset Aplha Phase: Final Technical Report
Mar 2026
Publication
Rosen,
National Gas and
Cadent
HyNTS is a programme of work that seeks to identify the opportunities and address the challenges that transporting hydrogen within the National Transmission System (NTS) presents. This will unlock the potential of hydrogen to deliver the UK’s 2050 Net Zero targets. The programme will feed into a number of ongoing hydrogen initiatives such as Project Union which has the aim of creating a UK hydrogen transmission backbone for the UK using repurposed and new-build infrastructure.
The Pipeline Dataset SIF project has two primary objectives.
♦ Defining and gathering the data necessary to ultimately facilitate repurposing of above 7 bar pipelines on the NTS and LTS.
♦ Developing the tools and processes to store align and visualise data to facilitate effective Integrity Management decision-making during post-repurposing service.
This report provides a summary of the work completed in the HyNTS Pipeline Dataset project Alpha phase to address these objectives.
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.
The Pipeline Dataset SIF project has two primary objectives.
♦ Defining and gathering the data necessary to ultimately facilitate repurposing of above 7 bar pipelines on the NTS and LTS.
♦ Developing the tools and processes to store align and visualise data to facilitate effective Integrity Management decision-making during post-repurposing service.
This report provides a summary of the work completed in the HyNTS Pipeline Dataset project Alpha phase to address these objectives.
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.
HyNTS Compression, Alpha Technical Report
Mar 2026
Publication
The HyNTS Compression project investigates the key challenges associated with compression of hydrogen and hydrogen blends through NTS assets. The project will determine the most cost-effective technically feasible solution for hydrogen compression on the NTS and develop the strategy for hydrogen compression. The alpha phase of the project has focussed on the following before progression to the beta phase of the project:
• Business case and Requirements for hydrogen compression
• Gas Turbine System
• Compression System
• Ancillary Equipment
• Demonstration Facility Development
The conceptual design development has concluded that it is possible to repurpose existing compression assets to demonstrate their capability of operating with 100% hydrogen. This will obtain the evidence necessary to update the Safety Case to enable deployment across the NTS. This phase of work further reinforces the importance of carrying out a demonstration to gather evidence of how repurposed compression assets would operate and the impact this would have on their performance. If repurposing NTS compression assets for hydrogen service can be proven there is potential for huge savings when realised across the entire NTS compression fleet.
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.
• Business case and Requirements for hydrogen compression
• Gas Turbine System
• Compression System
• Ancillary Equipment
• Demonstration Facility Development
The conceptual design development has concluded that it is possible to repurpose existing compression assets to demonstrate their capability of operating with 100% hydrogen. This will obtain the evidence necessary to update the Safety Case to enable deployment across the NTS. This phase of work further reinforces the importance of carrying out a demonstration to gather evidence of how repurposed compression assets would operate and the impact this would have on their performance. If repurposing NTS compression assets for hydrogen service can be proven there is potential for huge savings when realised across the entire NTS compression fleet.
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.
Multiphysical Coupling Analysis of Sealing Performance of Underground Lined Caverns for Hydrogen Storage
Nov 2025
Publication
Shaodong Cui,
Yin Li,
Junwu Zou and
Yun Chen
The accurate analysis of the sealing performance of underground lined cavern hydrogen storage is critical for enhancing the stability and economic viability of storage facilities. This study conducts an innovative investigation into hydrogen leakage behavior by developing a multiphysical coupled model for a composite system of support structures and surrounding rock in the operation process. By integrating Fick’s first law with the steady-state gas permeation equation the gas leakage rates of stainless steel and polymer sealing layers are quantified respectively. The Arrhenius equation is employed to characterize the effects of temperature on hydrogen permeability and the evolution of gas permeability. Thermalmechanical coupled effects across different materials within the storage system are further considered to accurately capture the hydrogen leakage process. The reliability of the established model is validated against analytical solutions and operational data from a real underground compressed air storage facility. The applicability of four materials— stainless steel epoxy resin (EP) ethylene–vinyl alcohol copolymer (EVOH) and polyimide (PI)—as sealing layers in underground hydrogen storage caverns is evaluated and the influences of four operational parameters (initial temperature initial pressure hydrogen injection temperature and injection–production rate) on sealing layer performance are also systematically investigated. The results indicate that all four materials satisfy the required sealing performance standards with stainless steel and EP demonstrating superior sealing performance. The initial temperature of the storage and the injection temperature of hydrogen significantly affect the circumferential stress in the sealing layer—a 10 K increase in initial temperature leads to an 11% rise in circumferential stress while a 10 K increase in injection temperature results in a 10% increase. In addition the initial storage pressure and the hydrogen injection rate exhibit a considerable influence on airtightness—a 1 MPa increase in initial pressure raises the leakage rate by 11% and a 20 kg/s increase in injection rate leads to a 12% increase in leakage. This study provides a theoretical foundation for sealing material selection and parameter optimization in practical engineering applications of underground lined caverns for hydrogen storage.
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