Net zero and the energy system transition
Hydrogen Refuelling from the Network
Wales & West Utilities (WWU) is undertaking a project to develop a thorough understanding of the technical and economic requirements for integrating hydrogen refuelling stations (HRS) into the existing gas network. The main aim is to enable the supply of ‘on-spec’ hydrogen for fuel cell electric vehicles (FCEVs) and hydrogen internal combustion engines (HICEs) from the heat-grade hydrogen currently delivered by the network. This involves analysing the types of contaminants present in grid hydrogen pinpointing the purification technologies needed and assessing the infrastructure requirements for compression chilling and storage to deliver hydrogen at the target pressures of 350 and 700 bar.
Hydrogen Fuel Cell Operating Hub for Repex/Large-Scale Projects
To maintain their above ground and underground pipework assets all Gas Distribution Networks (GDN) operate substantial fleets of commercial vehicles (primarily vans but also HGVs) together with mobile plant and powered equipment. Presently there is a complete reliance on hydrocarbon fuels primarily diesel and petrol. Both fuel types are usually sourced via the public retail forecourt network. Similar issues exist for other utility providers that operate underground and overground infrastructure.
Wales & West Utilities is undertaking a major programme of change to support decarbonisation and deliver a hydrogen-ready Net Zero gas network. Our distribution network iron mains replacement programme (Repex) requires significant excavation and pipe replacement activity laying long-life hydrogen-ready polyethylene pipe by a variety of means.
The project endeavours to identify a suite of suitable zero-emission mobile plant assets tools and equipment for carrying out Repex work that WWU could hire or purchase for operational trials and to identify opportunities for changing equipment items to simplify recharging/refuelling requirements in the future.
The objectives of this project are:
- To analyse current energy demands sound pressure and vibration levels associated with existing ICE powered mobile plant assets ICE-powered tools and equipment and electrical equipment used for carrying out planned iron mains replacement work on the gas distribution network.
- To estimate the future electrical energy demands (and sound pressure and vibration levels) placed by future zero-emission powered tools and equipment on a zero-emission site-based power generation facility.
- To identify opportunities for changing equipment items to simplify recharging/refuelling requirements in future.
- To identify a suite of suitable zero-emission mobile plant assets tools and equipment that WWU could hire (or purchase) and utilise for operational trials short and longer term. This will include the energy source and the means of recharging and/or refuelling on site and/or at regional depot locations.
Variable Blends Operational
Blending hydrogen and natural gas into the NTS has some clear benefits for supporting the transition of the energy industry in the UK to net zero in 2050 and is seen as an important intermediary step towards that goal.
It is expected that initially a low percentage hydrogen blend will be accepted onto the National Transmission System with this potentially increasing up to 20% hydrogen blends being accepted. However whether a hydrogen producer has to put in a specific blend percentage has not been determined and is unlikely. Therefore NGT need to develop the system to be able to effectively manage variable blends in addition to 2% 5% and 20% hydrogen blends.
This project will look into 4 key areas that might be directly impacted by hydrogen blend variability and require impact and risk assessments followed by investigations resulting in solution mapping and mitigation strategies being proposed. The key topics include establishing permissible limits for variability investigating how to manage interconnection from NTS to other countries understanding the effects of variability on stratification potential in the network and investigating the effects of variability on combustor/compression modelling.
HyNTS Operational Methodologies - Valve Performance Assessments
This project aims to assess and enhance the hydrogen readiness of ball valves within the (NTS) by conducting maintenance strategy evaluation with material performance analysis. It involves reviewing current valve operations diagnostics and OEM maintenance guidance alongside a literature review of commonly used valve materials to understand their behaviour under hydrogen exposure. The project valve performance testing and finite element analysis of existing valve designs to evaluate structural integrity. Findings from these activities will provide actionable recommendations for updating NGT’s valves maintenance strategies diagnostic tools and design standards to support safe and efficient hydrogen service deployment
HyNTS Operational: Qualification of Pressure Vessels
The National Transmission System (NTS) uses dry scrubbers filters and strainers to remove contaminants in the gas stream. Introducing hydrogen raises new challenges due to its distinct properties which could affect the performance and efficiency of these existing cleaning assets. We completed a project that investigated the compatibility of these assets with hydrogen and hydrogen blends to ensure gas quality without compromising the safety or efficiency. An outcome was to get a deeper understanding of the fracture and fatigue behaviours of these equipment to better understand whether hydrogen will impact the material properties. This assessment will undertake a targeted CTR analysis to inform a future potential physical test programme.
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.
Girth Weld Inspection of Steel Pipelines for Repurposing to Hydrogen Service
Repurposing of natural gas pipelines made of carbon steel for use with hydrogen blends requires a fitness-for-service analysis as part of the hydrogen use safety case. Girth welds of an unknown quality exist in the Local Transmission System (LTS). In hydrogen service these welds would have a greater susceptibility to fracture failure due to material embrittlement caused by interaction of steel material with hydrogen.
Current in-line inspection methods do not routinely inspect girth welds for defects. This project aims to test the available technology for its capability to detect defects and cracks in girth welds. This will provide valuable data for engineering critical assessments required to repurpose natural gas pipelines. It will also inform about the state of art inspection techniques and whether they can be used as a tool for repurposing pipelines.
Hydrogen Combustion Engine Feasibility Study
This project will see Cenex deliver a feasibility study on hydrogen internal combustion engines (H2ICE) as an alternative to diesel and Fuel Cell Electric Vehicle (FCEV) within WWU’s operational fleet. This project comprises three distinct work packages (WPs) each feeding into a holistic assessment of H2ICE applicability across WWU’s vehicle assets. Cenex will apply its expertise in fleet decarbonisation alternative fuel technologies legislative policy analysis and techno-economic modelling to meet WWU’s scope requirements. All outputs will be suitable for internal strategic review and for sharing externally with partners and stakeholders.
Blending Management Approach – Phase 2
The conversion of the National Transmission System into a hydrogen transmission network has been widely discussed and it is recognised that blending of hydrogen and natural gas in the network is an important intermediary step towards that goal. It is therefore important to understand how the NTS will operate with a mix of natural gas and variable blends up to 20% hydrogen.
The Blending Management Approach (BMA) Phase 2 project will explore the operational safety and strategic implications of introducing low-level hydrogen blends into the National Transmission System (NTS) with a particular focus on storage interactions emergency response scenarios and long-term network management strategies. This phase aims to deepen understanding of how hydrogen blends interact with existing infrastructure and protocols.
Scaling Hydrogen with Nuclear Energy (SHyNE)
Significant efforts are required to support the transition of our energy systems moving away from carbon-intensive fuels such as coal diesel petrol and gas towards cleaner sources of power generation such as wind solar nuclear and hydrogen. There is a potential for hydrogen to play a hugely significant role in our energy system the extent of which will be driven by a range of factors including the ability to transport it to where it is needed. There have been recent positive decisions for hydrogen’s potential uses in blending transportation domestic heating and industry. To produce sufficient hydrogen to meet this potential need it will be important to increase and diversify hydrogen production methods.
As nuclear is a reliable and consistent source of clean energy that is unaffected by external factors such as the weather Northern Gas Networks and Wales and West Utilities would like to investigate the possible use of nuclear power as a method of delivering the future increased demand in hydrogen production. This project will explore the opportunity for hydrogen production from nuclear to support a net zero transition across the gas network.
Benefits of nuclear-enabled hydrogen (NEH) in the context of gas distribution networks (GDNs) will be explored building on the established benefits of nuclear energy production.
The overall project outcome is that NGN WWU and other stakeholders are sufficiently informed to determine whether further investment and integration of nuclear-enabled hydrogen to transition plans are justified and how a potential first project could take its next step to deployment through securing technology licences sites off takers and financing.
Risk of Microbial Corrosion due to Hydrogen Transportation
National gas pipeline systems rely heavily on protective coatings and cathodic protection to prevent corrosion and ensure long-term integrity. Coatings act as the primary barrier against environmental exposure while cathodic protection—typically using sacrificial anodes or impressed current systems—supplements this by mitigating electrochemical reactions that cause metal degradation. The introduction of hydrogen into these pipelines as part of decarbonization efforts presents new challenges. Hydrogen can permeate coatings and accelerate corrosion processes especially in the presence of certain microbes. Microbiologically induced corrosion (MIC) driven by bacteria such as sulphate-reducing bacteria (SRB) can be exacerbated by hydrogen which some microbes use as an energy source. This interaction may compromise both the coating and cathodic protection systems necessitating advanced materials and monitoring strategies to maintain pipeline safety and performance in a hydrogen-integrated future.
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.
Development of Technical Readiness for Bends and Tees
Hydrogen design codes require fracture mechanics based design and qualification for high stress service. Procurement of a number of Long Lead Items (LLI) is required to construct commission and operate hydrogen networks. A number of these LLIs including induction bends and barred tees remain at a low technical readiness.
This project will carry out fracture toughness testing in a hydrogen environment to increase the technical readiness support the supply chain and achieve operational schedules.
High-Pressure Materials Analysis (HPMA)
This project will identify and evaluate current technology available for pipes suitable for use in natural gas blended gas and hydrogen gas networks operating above 7 bar.
This project will see QEM Solutions conduct a comprehensive literature review of market reports on pipes used in high-pressure gas systems as well as of existing options for transportation of high-pressure gas in industrial uses with transferrable learnings. QEMS will develop a matrix comparing pros and cons of each solution and consolidate the findings into a final project report.
The project will facilitate the energy system transition by investigating the available and most optimal pipeline materials for natural gas blended gas and hydrogen gas networks above 7 bar considering all operational capex requirements and full lifecycle costs. This work is important for informing investment decisions in pipeline replacement materials addressing a gap in current knowledge.
Alt Pipe
As the owner of the National Transmission System (NTS) National Gas is committed to responsibly managing our redundant assets in a manner that contributes to a sustainable lower-carbon future by decommissioning them responsibly refurbishing for re-use where viable and/or or changing their purpose where possible. This discovery project will identify decommissioned elements of redundant pipework on the transmission system which are unlikely to be used for refurbishment or part of any wider repurposing of the core network and explore the potential of repurposing these for alternative uses including the storage and/or transmission of electrical energy heat fuels water and data.
INNOVATIVE MONITORING AND CONTROL OF PIPELINE CONSTRUCTION
Cadent proposes to trial “Digital Inspector” (DI) an innovative platform that enhances real-time control inspection and recording of pipeline construction activities. Digital Inspector provides verifiable evidence of weld quality supervises critical parameters live during construction and generates a complete digital record for asset integrity.
This project will trial Digital Inspector across multiple Cadent construction projects in 2025/26 working closely with Cadent’s contractors to assess practical usability contractor acceptance and the impact on existing BAU processes.
Maximising Capacity at Biomethane Sites
This project will develop network and/or entry site solutions that will enable biomethane supply to meet the swings in demand through the year.
H100 Barhole Trials for Hydrogen Network Operations
This project will focus on barholing operations conducted after an emergency gas escape within the H100 Fife Distribution Network Operations. The scope will consider H100 scenarios specifically the establishment of a new distribution network to deliver Hydrogen to selected properties in the conversion area. The minimum pressure for the H100 Fife Distribution network is 27 mbar and the maximum pressure is 75 mbar. The aim of this project is to provide further evidence to support SGN operations on the H100 distribution network during emergencies and any future trials or broader rollouts of Hydrogen.
Steer Energy has been identified as a suitable contractor for executing this project due to their extensive expertise in this field and their previous work on the Barhole Trials and ITL Haldane Drill Isolator project. Steer has a proven partnership with SGN and the wider gas industry offering a variety of services including experimental lab testing training and testing facilities.
Development of Technical Readiness for Large Diameter Ball Valves
In order to construct commission and operate new hydrogen pipelines and installations safely and as part of modifications to existing assets for repurposing ball valves are required to carry out isolations. Selected ball valves need to have been proven to be suitable for service in large diameter high pressure hydrogen networks.
This project will carry out performance validation testing on a 32″ ball valve to confirm suitability to operate in high pressure hydrogen networks.
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.