Net zero and the energy system transition

This project will explore the feasibility of integrating hydrogen train refuelling infrastructure to support the development of a hydrogen rail network. This has particular relevance to our network as some of the UK’s hardest to electrify rail routes are situated in Wales and South West England. The project will focus on these hard to electrify routes exploring H2’s potential role in enabling their decarbonisation. If successful this project can help the WWU network to become a proving ground for real-world delivery of impactful H2 rail technology. It is expected to provide information which can be used in planning strategic hydrogen pipeline routes and network repurposing plans and support regional energy planning.

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.

The project described covers the development of a new repurposing process for NTS assets to transport gaseous phase carbon dioxide. The approach for repurposing the National Gas Transmission System (NTS) to transport carbon dioxide will need an innovative approach to meet the timelines for the net zero transition. There have been several projects undertaken to date to determine the interactions of carbon dioxide with the network assets. We are looking to determine if these activities are providing all the relevant data and evidence required for our network to transition.

This Network Innovation Allowance (NIA) project investigated dew point management in hydrogen/natural gas blends pure hydrogen and carbon dioxide transmission pipelines. In the National Transmission System (NTS) which is currently a natural gas network the purity of the gas is carefully controlled via the network entry specification. Trace components such as water nitrogen oxides sulphur containing compounds oxygen and carbon dioxide have strict limits on their allowable levels in the network. This is done in part to ensure the gas delivered to end users meets the requirements of the customer but also to protect transport and storage systems. Purity specifications are being developed for hydrogen its blends with natural gas and for carbon dioxide (CO₂). This project focused specifically on the water content within these gases in what concentrations it is likely to be acceptable the conditions at which it may condense in the network its interactions with other trace components and contaminants and the potential detrimental effect on the network.

Limiting moisture content and ensuring gas dryness is important for several reasons:

• Safety & Efficiency: Hydrogen’s efficiency as a fuel can be compromised by moisture. Water in hydrogen can affect the combustion process leading to a reduced efficiency for applications like gas turbines.
• Corrosion: If dew points aren’t controlled effectively liquid can drop out of the gas phase and this moisture can cause corrosion in pipelines and hydrogen embrittlement. For CO₂ pipelines this moisture can react to produce carbonic acid which can further corrode the pipelines.

The outcomes of the project should provide a clearer insight and strategy on how to effectively manage hydrogen and carbon dryness within the NTS ensuring that the gas remains within the required specifications for current and future demands.

The project was split into three work packages (WP):

1. WP1 focused on hydrogen and its blends initially reviewing the equations of state (EoS) that model the dew point temperature at varying water content and hydrogen/methane blend ratios. The impact on the network of liquid water formation in hydrogen was examined including the interaction with other trace components such as CO₂ and H₂S in particular the effect on welds and pipeline defects. Finally a summary of international standards for hydrogen purity highlighted the likely water content limits that could be expected by hydrogen users and thus provided by producers.

2. WP2 focused on CO₂ its phase behaviour and the effect impurities have on this behaviour using the most appropriate equations of state. The detrimental effect of CO₂ and liquid water contained within it on pipelines fittings and other parts of the network was reviewed.

3. WP3 focused on how the water content specifications could be managed on the network from the point of view of monitoring and controlling water dew point in the gases. The water content expected from various production techniques were reviewed and a high-level costing for the dehydration process for both CO₂ and hydrogen was made.

National Gas Transmission (NGT) own and operate the UK’s National Transmission System (NTS) transporting natural gas from terminals to end users. NGT have ambitions to repurpose the existing to transport hydrogen and hydrogen blends. Understanding the impact of hydrogen on our existing assets is a key enabler for this.

This project will conduct design of flare for hydrogen and its blends and vent system for hydrogen its blends and carbon dioxide and offline physical testing to provide evidence that hydrogen / hydrogen blends could be flared and vented safely and environmentally in for NTS.

This project investigates the risk of air ingress in medium to large commercial gas installations particularly in the context of hydrogen transition. It builds on previous domestic-focused research and aims to understand whether similar risks and mitigation strategies apply to commercial systems. The project includes technical and behavioural assessments experimental testing analytical modelling and the identification of mitigation measures.

NGT is committed to supporting the government and the broader industry in achieving the Net Zero target by 2050. CCUS alongside hydrogen will play a critical role in reaching this goal. Since the existing infrastructure was originally designed for methane adapting it to transport these new gases presents significant engineering challenges. To address this an extensive research program has been launched to assess the technical feasibility of repurposing sections of the NTS for hydrogen and carbon dioxide transportation. While repurposing existing pipelines will be an essential part of the transition it will not be sufficient new infrastructure will be required to support a scalable hydrogen and carbon network. Given the ambitious deployment timelines meeting these targets will require not only innovative technical solutions but also a holistic strategy that integrates the supply chain and fosters collaboration across the industry.

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 Special Condition 5.6. 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.

This project will develop and evaluate a predictive flood monitoring system for Above Ground Installations (AGIs) and pipeline assets using real-time sensor data and 48-hour surface water forecasting. The system will be deployed at four locations identified through a nationwide flood risk survey. The trial will assess the system’s accuracy responsiveness and operational value across diverse environments. The project supports climate adaptation regulatory compliance and asset resilience by enabling early warning and proactive intervention. It aligns with RIIO-2 NIA objectives by reducing flood-related disruption enhancing safety and informing future investment decisions. The project will conclude with a technical report and recommendations for wider rollout under RIIO-3.

As the hydrogen economy grows the need for flexible decentralised intermediate-scale hydrogen storage is becoming increasingly evident. While large-scale underground hydrogen storage in salt caverns and depleted gas fields will play a crucial role in long-term energy security distributed intermediate scale storage solutions are essential to bridge the gap between production and end-use ensuring reliability efficiency and resilience in hydrogen supply chains during the scale-up of the hydrogen economy. Decentralised storage facilities allow for hydrogen hubs to emerge in urban and industrial areas reducing reliance on long-distance transport infrastructure and supporting regional hydrogen economies.

A key unknown is whether the land use and geology of Wales and South West England can support intermediate-scale underground hydrogen storage (UHS) technologies. This project aims to map and assess potential storage sites within the WWU region aligning with broader energy infrastructure plans—including hydrogen and gas pipelines electricity networks industrial demand and renewable energy integration. The project will use WWU’s geology and geography as a case study and demonstrate how UHS options can support wider energy infrastructure in the region and beyond as well as future project plans. For this reason the outputs are expected to be of value to all networks.

To evaluate the feasibility of these storage solutions the University of Edinburgh will analyse rock property and strength data from publicly accessible British Geological Survey (BGS) datasets developing new insights into the engineering suitability of the region’s subsurface for hydrogen storage.

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:

1. 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.
2. 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.
3. To identify opportunities for changing equipment items to simplify recharging/refuelling requirements in future.
4. 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.

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

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.

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.

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.

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.

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.

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.

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.

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.

Clean Power 2030 (CP2030) aims for a fully decarbonised electricity system using unabated gas only as backup. This introduces an important challenge: how can the gas transmission network remain viable and deliver flexibility during extreme demand events despite not being utilised most of the time? This project aims to understand how to sustain the gas network technically and economically in a low average high peak demand future focusing on the interaction between gas and electricity systems.

This project will conduct market research on available or soon to be available hybrid products for discussion and presentation back to WWU and WW Housing to choose a preferred solution for the properties identified that are suitable to trial the equipment in. The project will provide networks with demand data and look to aggregate this over WW Housing stock to understand wider impact on gas networks if this was considered a viable option to decarbonise housing stock.

GNES (Gas Network Evolution Simulator) uses Agent Based Modelling to simulate how people policies and infrastructure interact as the UK transitions away from natural gas. By reflecting real-world behaviours and decisions it helps energy networks policymakers and communities explore fair cost-effective pathways to decarbonisation. GNES reveals how transition choices impact different households and regions ensuring no one is left behind. Developed by the Centre for Energy Equality with industry and public partners GNES supports a whole-system approach to planning a just and resilient energy future that works for everyone not just those able to move first.

The key subject of HIRSA stage 2 projects is to understand if using hydrogen in the gas network will result in an increased likelihood of ignition from static discharge generated by particulates in flowing gas. Building on stage 2A stage 2B will provide further experimental testing aimed at determining the absolute difference in electrostatic charge generated identify whether any external factors impact one gas more than the other and to control the factors affecting generation of the charge. The outputs of this work should provide the industry with a better understanding of the potential change in ignition risk when switching from Natural Gas to hydrogen and will also highlight relevant mitigations to manage this risk.

Following completion of Phase 2 of the H21 Hydrogen Ready Components project this project will look to extend the methodology developed under this project to encompass the assessment of assets operating above 7 barg. The assessment tool will be incorporated into the LTS Futures blueprint methodology for repurposing existing Natural Gas transmission assets to hydrogen. The scope will include transmission assets above 7 barg and up to the maximum transmission pressure of 94 barg and will focus on the conversion to 100% hydrogen. Assets in scope will cover both above and below ground assets and include bends valves regulators slam shuts relief valves and pig traps. Assets excluded include pipelines compressors and cast iron components.