Net zero and the energy system transition
Preferential Emissions Study
The characteristics of transmission pressure hydrogen and natural gas blends are not fully understood including relative leakage behaviour. Existing evidence for leak behaviour of hydrogen blends do not extend above 7barg and therefore do not account for the effects of transmission pressures on gas behaviour. This project will test whether or not methane and hydrogen within a blend leak at the same rates or whether due to its small size hydrogen will leak at a ratio greater than its relative concentration and whether it leaks where methane does not.
Understanding the leak behaviour of hydrogen in a natural gas blend will ensure we can operate a blended system safely particularly in enclosed spaces and will ensure that the carbon benefit of hydrogen enrichment is not lost through fugitive emissions. Also as green hydrogen is currently significantly more expensive than natural gas the shrinkage costs associated with hydrogen fugitive emissions could be considerable.
Predictive Tool for Unaccounted-For Gas (UAG) Identification
The Unaccounted-for Gas (UAG) project aims to develop a predictive tool that identifies and quantifies UAG across the National Transmission System (NTS). Leveraging 12-18 months of SCADA data the tool will simulate gas flow and metering behaviour to pinpoint anomalies and reduce losses. UAG currently represents significant financial cost to the consumer; even a 1% reduction could yield practical savings. The project aligns with RIIO-2 NIA criteria and supports regulatory compliance under the Gas Transporter Licence Part J of Special Condition 5.6 (System operator external incentives revenues and costs) requiring National Gas to undertake work to investigate the causes of UAG. It builds on prior research and integrates learnings from international benchmarks. The initiative will enhance operational efficiency improve data transparency and support long-term decarbonisation goals through better system visibility and control.
HyNTS Operational - Qualification of Pressure Vessels
This project assessed whether a fracture mechanics approach can be used to justify existing gas cleaning scrubbers for future hydrogen or hydrogen blend service. The work focused on a representative Kings Lynn scrubber and considered crack-like flaws hydrogen-affected toughness residual stresses pressure cycling and fatigue crack growth. The results indicate that the approach is viable for demonstrating integrity in large parts of the scrubber particularly the upper vessel and nozzle welds but further evidence is required before it can be applied across the wider scrubber population.
Impact of Hydrogen and on NTS Oils & Greases – Phase 2
Phase 1 of the project compiled a list of oils and greases considered to be gas-facing on the NTS along with identifying functional and material property requirements of these products. Proposed standards and testing methodologies were also outlined to inform the next phase of the project. In Phase 2 the project will proceed with additional required activities to ensure the safe utilisation of NTS oils/greases in a hydrogen pressurised environment. These activities include laboratory testing for lubricants and functional testing for sealants to assess degradation and performance of these products in hydrogen. Subsequently requirements for in-service monitoring will be identified.
NTS Pipeline Assessments Phase 2
This project will build upon previous work to inform decisions relating to the repurposing of National Transmission System pipelines for 100% hydrogen and hydrogen-natural gas blends. New input data will be generated and collated the assessment methodology will be refined and an alternative assessment method probabilistic will be utilised and the resulting network impact will be considered.
This project will generate the following benefits:
- More accurate assessment of the capability of the NTS to transport 100% hydrogen and hydrogen-natural gas blends.
- Data on the impact of low percentage blend hydrogen on pipeline materials.
- Standardised document for Engineering Critical Assessments (ECA) of hydrogen and hydrogen-natural gas blend pipelines and pipework.
Greater understanding on the effect of hydrogen on the design and operation of pipeline systems.
Gas Inhibitors for Hydrogen Pipelines - Phase 3
The Phase 3 project on gas inhibitors for hydrogen pipelines aims to translate lab-scale findings into practical applications for the UK’s National Transmission System. It focuses on validating the effectiveness of oxygen and alternative inhibitors in mitigating hydrogen embrittlement addressing unresolved safety and integrity concerns from previous phases and designing a plan for safe integration into existing infrastructure. The project includes physical demonstration planning and network design to assess technology implementation.
H2 Site Safety Systems
This project will examine the suitability of existing Fire and Gas (F&G) detection and suppression systems for use with hydrogen blends of up to 20%. These systems comprise: fire detection fire suppression gas detection and associated control systems. They are found in compressor cabs and at network terminals.
Through CFD modelling three representative F&G systems will be individually assessed for compatibility with blends and will then be used as examples to make comments on the suitability of other F&G systems on the network. Where assets or control systems are not suitable this project will not design a new system but recommend where changes should be made and demonstrate how those changes safely manage risk – including cost estimation for upgrade or retrofit.
Integrity Management of Hydrogen Pipelines
Existing defect assessments and repair methodologies designed for natural gas service are aligned with the T/PM/P/** and T/PM/P/** management procedures and are adopted to inspect assess and repair pipelines for defects and take suitable measures to mitigate them. However the scope and applicability of the assessment inspection and repair techniques in the presence of high-pressure hydrogen remain uncertain. The key questions which form an outline of the project are:
- What are the different types of defects we may encounter or consider injurious in the presence of hydrogen?
- What is the impact of hydrogen on each defect type? Have the mechanisms of failure changed for each defect type after hydrogen-natural gas blending?
- Will the existing repair techniques be applicable under transmission of high-pressure hydrogen and hydrogen-natural gas blends?
- Can we implement the defect assessment inspection and repair methodologies safely? Are the techniques safe and suitable for the pipeline operations and maintenance teams?
The project seeks to answer the above in addition to understanding the types and extent of repairs across the NTS and assess the impact of hydrogen on the effectiveness of these inspection assessment and mitigation technologies.
Application of Functional Blending - Testing a Market-led Approach
Wales & West Utilities has developed a Regional Decarbonisation Pathway to provide an overarching strategic plan for the network in Wales and the South West of England. To deliver that pathway more detailed assessment and planning is required to facilitate the progression of opportunities in particular areas.
In 2023 WWU supported Cadent as the lead partner in the development and delivery of a Functional Blending Specification (FBS) which has progressed the technical understanding of how blending equipment can be practically applied within the context of existing gas network assets (
Rising Pressure Reformer Study
This project will assess the application of Rising Pressure Reformer (RiPR) technology to produce a tuneable blend of biogenic methane and hydrogen supporting the decarbonisation of gas networks. The project will focus on the how control of the gas produced would fit with requirements for network injection and assessing locations for connection.
Energy Plan Translator
Develop a flexible and adaptable toolset for the rapid analysis of Local Area Energy Plans (LAEPs). This will convert qualitative statements to quantified metrics and identify key network specific planning parameters.
Energy Plan Translator
Develop a flexible and adaptable toolset for the rapid analysis of Local Area Energy Plans (LAEPs). This will convert qualitative statements to quantified metrics and identify key network specific planning parameters.
Stopple-Live trial (Phase 2)
The Stopple technology is a flow stop tool essential for major projects and emergency works across the LTS and NTS gas network. Its capability was tested in 100% hydrogen within a helinite environment in line with LTS Futures parameters as phase 1. This project focuses on validating flow-stopping technology as an additional deliverable with LTS Futures live hydrogen trial on the Granton to Grangemouth pipeline as a welded tee and hot-tapping operations is already being carried out. The trial will confirm the Stopple train’s effectiveness as a double-block and bleed solution for a 100% hydrogen system which will be available for the UK Gas Network. The findings will provide critical insights into the safe and efficient operation of the hydrogen networks supporting the transition from natural gas to hydrogen.
EPRG - European Pipeline Research Group 26.27
The European Pipeline Research Group (EPRG) undertakes a wide range of research directed towards the increasing integrity and safety of gas pipelines. Topics such as fit for purpose assessments pipeline rehabilitation & repair techniques and corrosion constitute the major areas of concern for existing pipelines. EPRG projects heavily focus on design and construction of new pipelines through researching materials that allow for increased operational pressures and reduced pipeline thickness while maintaining safety. EPRG are involved with defect assessment and fracture management where the create guidelines to assess the severity and risk of detected defects in pressurised gas pipelines. Conducting full scale material tests to understand crack propagation under cycling loading or harsh environments forms the basis for fracture and fatigue studies. Collaboration on international research programmes through industry bodies such as EPRG is essential to ensure we benefit from leveraged research. Continued participation in EPRG allows National Gas Transmission and Cadent Gas to develop a breadth and depth of knowledge that can only be realised through leveraged research programmes providing maximum cost effectiveness to the customer.
Hydrogen Blending: Direct Injection Feasibility Study
This project has been initiated to assess the technical and commercial feasibility of direct hydrogen injection into the gas distribution network at 5% and 20% by volume. It supports the broader Market Frameworks appraisal by providing the evidence needed to evaluate whether both System Entry Models direct injection and pre-blending are feasible under varying network conditions.
The need for this study was identified through the Hydrogen Blending Implementation Plan which outlined two technical approaches for hydrogen connections: injecting hydrogen directly into the network or pre-blending it before entry each with distinct technical and commercial implications. While National Gas has assessed both models for the transmission network a gap analysis revealed that these findings are not directly transferable to the distribution network.
Evidence for pre-blending was previously completed as part of HyDeploy and the Hydrogen Blending Functional Specification project. It was shown that this approach provides more controlled mixing but may require more complex infrastructure leading to higher costs for the producer. Although it is assumed Direct Injection may be achievable at lower cost there are multiple key technical challenges associated with the technique such as the potential for inadequate hydrogen mixing which could result in non-compliant gas safety concerns including material integrity and operational constraints e.g. GSMR exclusion zones.
Through literature review CFD modelling engineering assessments and commercial analysis the study will evaluate the technical and safety performance risks and cost implications of direct injection across a range of scenarios and configurations.
Net Zero Multi-Vector Assessment
This project will help Cadent to understand considerations for a Net Zero Multi-Vector at a town scale to inform future activity on preparation for repurposing. An area will be chosen which is representative of different networks housing stock and demographics which will require different approaches and engagement.
Excess Flow Valve (EFV) Durability
This project will help to inform UK Gas Distribution Network Operators (GDNOs) and wider industry on the long-term suitability of existing Excess Flow Valve (EFV) designs in a future where hydrogen is being distributed in network pipelines. A risk to normal EFV functionality exists in the event that an ignition occurs within the downstream gas installation pipework and this project will help to understand the effectiveness of existing EFV designs to manage this risk identifying any necessary modifications to existing EFV designs where appropriate.
Asset Records Readiness for Hydrogen
The project will evaluate and deliver a plan that ensures our asset records are suitably complete to support the net zero transition.
The project will reduce uncertainty and risk and provide a more realistic proximation of asset data.
The HSE has indicated that it will be unable to support a network’s hydrogen safety case until they receive “a clear plan for checking unknown assets and how networks will ensure that only suitable materials are present in the network”. This includes our transmission pipelines.
Additionally for the marginal extra effort it would be prudent to ensure the completeness of our asset records is sufficient for us to either plan for the conversion to hydrogen or decommission sections as users switch to other heating technologies.
Accuracy of electronic volume conversion systems when metering blends of hydrogen and natural gas
This project focuses on ensuring accurate volume conversion within gas metering processes as hydrogen is blended into the natural gas network across Great Britain. Accurate measurement is essential for fair billing and maintaining customer trust during the energy transition. The project will study real world metering installations assess potential errors caused by hydrogen blending and develop practical mitigation strategies. Findings will inform updates to industry guidance (IGEM/GM/5) supporting regulatory compliance and operational integrity.
Biomethane HP storage injection
To investigate the potential to use high pressure storage assets to directly inject biomethane.