Net zero and the energy system transition
Hydrogen Environment Testing of Girth Welds Phase 2 - Constant Load Testing
Previous testing carried out under NIA has outstanding gaps that require further testing to close. Completing the additional testing will confirm actual fracture toughness values to be used and the corresponding J value from the crack growth resistance curve. The project outputs are required and will be used to progress design specification and procurement processes for hydrogen major projects. The results can also be applied for repurposing assessments.
Biomethane feedstock deliverability
Cadent have been working with The Green Gas Taskforce to commission a series of reports that examine the benefits of greater biomethane generation to Great Britain’s energy system as well as the economic benefits that such volumes of green gas could provide. Work conducted by Alder BioInsights in their “Green Gas Future” report concluded that biomethane volumes of 120 TWh are possible in the UK by 2050 based on technical potential of UK feedstocks.
This project seeks to explore the operational emissions market and developmental implications of meeting the potential volumes published by Alder BioInsights (120 TWh pa by 2050) as well as the implications of meeting the NESO FES 25 Holistic Transition scenario relating to the production of biomethane in the UK (36 TWh per annum by 2035 and 64 TWh per annum by 2050).
The conclusions of this project will be published in a public report entitled “Delivering Green Gas” that:
- Outlines the viability benefits and key questions behind the integration of the UK’s agricultural supply chain AD industry and gas distribution networks.
- Highlights where they may be trade-offs or unintended consequences introduced by scaling feedstock production for biomethane and if there are ways that these can be addressed to mitigate the impact.
- Defines concrete actions that need to be taken in the agricultural sector by agricultural policy makers and others to unlock the feedstock volumes set out in the Alder BioInsights work and the NESO scenarios where this is appropriate and doesn’t introduce undesirable consequences.
- Sets out the broader economic and environmental benefits that could be provided in delivering these volumes of biomethane beyond the energy sector and particularly to the UK’s agricultural sector.
Air Ingress in Multi Occupancy Buildings (MOBs)
This project will help to inform UK Gas Distribution Network Operators (GDNOs) and wider industry on the impact of the potential for air ingress into gas-conveying pipework in MOBs. The mechanisms for air ingress into gas-conveying pipework have been shown to be gas agnostic though this project will focus on impacts specific to future hydrogen distribution to MOBs.
MASiP Phase 3 (Qualification Testing & Integrated System Development)
The MASiP Phase 3 is developing a new pipeline system to serve as an alternative to conventional steel pipelines in the transmission network. The material used in this pipeline will render it capable of transporting natural gas biogas and up to 100% hydrogen. Building on Phases 1 and 2 this phase focuses on the technical assessment of tight radius bends tees and damage repair as well as the integration of live monitoring systems in a prototype operational environment.
Comprehensive validation will include connectors coatings repair systems hot-tapping solutions ground movement tolerance durability and design life testing. All testing will be carried out in accordance with IGEM API and ASME standards.
The key deliverable is a validated deployable hydrogen-ready pipeline system that is safe compliant and cost-effective offering potential cost savings of up to 50% compared with steel. The project outcomes will support the UK’s RIIO-GD2 strategy and 2050 net-zero targets by enabling hydrogen-ready infrastructure improving monitoring installation efficiency and long-term reliability while also providing the evidence base required for regulatory policy and industry acceptance of alternative pipeline materials.
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.
Catalysing Biomethane Growth in the UK
This project constitutes a UK-wide strategic assessment of the policy and regulatory frameworks governing biomethane production and grid injection with the objective of identifying how these frameworks can be updated to unlock growth. The review will examine the current policy landscape support mechanisms and regulatory arrangements affecting biomethane development including uncertainties associated with existing schemes and fragmented governance structures.
Calorific Gas Sensor
The UK and Irish gas networks are undergoing a major transition to support the integration of green gases including biomethane and hydrogen. A significant challenge is the inability of the current gas billing infrastructure based on flow-weighted average calorific value (CV) measurements taken at National Transmission System (NTS) offtakes to accurately reflect the gas composition received by consumers—particularly with the increasing number of decentralised injection points. This discrepancy presents a technical and regulatory hurdle to achieving fair and transparent billing.
This programme is leveraging 3 suppliers to develop a range of novel calorific value sensors that will enable calorific value to be accurately measured at different points on the network without the need for venting.
The programme comprises of 3 individual projects which will develop each suppliers’ technology up to a sufficiently high TRL where the sensors are ready to be trialled in the field. Each supplier will be delivering their own scope of work but will be expected to share a reasonable amount of information with each other in order to ensure maximum value is obtained from this programme. The innovators will not be expected to disclose any information that could provide them with a competitive advantage over the other solutions
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.
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.
Reducing Gas Emissions During Pipeline Commissioning
Based on previous work ROSEN Engineers believe the quantity of natural gas vented during commissioning operations can safely be reduced by up to 80% through targeted changes to direct purging procedures.
For Gas Distribution Networks’ (GDNs) gas venting remains a necessary part of normal operations for maintenance or safety purposes. Previous research work undertaken by ROSEN(UK) Limited for the EIC with project partners Northern Gas Networks (NGN) and Wales and West Utilities (WWU) identified activities where venting of natural gas to atmosphere occurs (Gas Venting Research Project NIA reference number NIA_NGN_282)
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.
Repurposing gas pipelines for SAF
This project evaluates the rapidly developing Sustainable Aviation Fuel (SAF) sector and assesses the technical commercial regulatory and safety feasibility of repurposing existing gas pipelines to transport liquid aviation fuels. The uptake of SAF is critical to decarbonising the UK aviation industry and achieving net zero targets. To support the scale-up of SAF production and use the development of reliable affordable and low-carbon infrastructure is essential. Pipelines offer a cost-effective environmentally sustainable and high-capacity transport solution. The study aims to enable scalable SAF infrastructure while providing a productive long-term use for gas assets that are unlikely to be required for refurbishment or alternative repurposing.
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.
Biomethane HP storage injection
To investigate the potential to use high pressure storage assets to directly inject biomethane.
Validation of Olfactory Assessment Methodology for 100% Hydrogen Network
To ensure that the users and general public recognise and report hydrogen leaks without further education current guidance states that the smell of hydrogen should be indistinguishable from that of natural gas. It is also expected that the same odorant will be used in hydrogen networks as is currently injected to natural gas and so it is essential to ensure that existing methodologies for olfactory assessment (Rhinology) originally developed for natural gas are safe effective and applicable to 100% hydrogen environments.
MOB Transition Pathways – Future Asset Integrity
The initial Hydrogen in MOBs project established the foundational evidence for hydrogen conversion and this follow-on project will address remaining evidence gaps identified by the CFA finalising the safety and regulatory case for MOB hydrogen conversion and enabling a clear handover of outputs to industry. This work also doubles up as an assessment of options we have today to deliver practical and safe designs introducing a new range of risk mitigation options which could be more cost effective and efficient way of managing MOBs and pipe assets. As a practical assessment of technical requirements for conversion this closes out CFA recommendations through applied testing to solve engineering and safety challenges but also informs current processes.
Key deliverables include validated technical data an updated Quantified Risk Assessment (QRA) for MOBs an updated management procedure and a revised IGEM/G/5 Hydrogen Supplement to be formally handed over to IGEM for review. Together these outputs will close out the regulatory and procedural workstream associated with hydrogen in MOBs research.
The project’s findings will also directly support the development of a decision-making framework to support refurbishment and riser replacement programmes. This will enable the industry to make consistent evidence-based decisions on the most appropriate options for MOBs including where alternatives to hydrogen may be more suitable.
Enhancement of the anaerobic digestion process for biomethane production
The UK Government recognised that domestic biomethane production can play a significant role in decarbonising energy supplies. However biomethane production plants face technical and operational challenges. Currently the content of biomethane within biogas produced from the anaerobic digestion (AD) process is often only around 50%. This partial conversion results in lower yields for AD operators and an increase in costly gas scrubbing requirements. The increased presence of impurity gases also increases requirement for propanation to increase the calorific value high in both cost and carbon footprint.
This project seeks to address these challenges through the injection of green hydrogen into the AD process in specific quantities and at specific times to achieve greater conversion of carbon dioxide to biomethane within the acetogenesis stage of the AD process thereby increasing the yield whilst reducing the need for gas scrubbing and propanation.
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.
HyProximity
This project aims to develop a robust evidence-based framework to support the introduction of standardised separation distance tables for 100% hydrogen similar in format and function to those in IGEM/TD/3 for natural gas and hydrogen blends. This will address a gap in current standards for hydrogen. The Institute of Gas Engineers and Managers (IGEM) are providing resource to support the project and to update any necessary standards.
Network Blending Blueprint
The Technical Blueprint Project forms a critical enabling phase of Cadent’s Hydrogen Blending Implementation Programme. Its purpose is to translate existing high level hydrogen blending evidence into a detailed network specific asset level and operationally deliverable blueprint that defines what is required for the gas network to safely and compliantly accommodate hydrogen blends of up to 20% by volume once regulatory approval is granted.
While previous industry projects have established that hydrogen blending is feasible in principle many technical operational and cost decisions remain at an asset process system and people level. These gaps currently prevent informed investment decisions and cannot be addressed through business‑as‑usual activity. This project addresses that gap by undertaking structured technical validation impact refinement and mitigation definition across Cadent’s network with a particular focus on the North West and East Midlands as pilot regions.
The project will coordinate specialist technical suppliers to validate prior hydrogen impact assessments against the most up‑to‑date safety evidence identify and close remaining evidence gaps and determine clear final mitigation positions for all affected assets and operational activities. Outputs will be consolidated into a single integrated technical blueprint providing a sequenced and costed set of actions required to achieve “blend readiness”. Areas confirmed as having no impact will also be explicitly documented to avoid unnecessary future intervention and cost.
The Technical Blueprint will provide Cadent and wider GB networks with a robust evidence‑based foundation to support future regulatory submissions funding reopeners and implementation planning. Learning generated will be transferable across gas distribution networks supporting a coordinated cost‑effective and safe transition toward hydrogen blending while reducing long‑term consumer risk and avoiding premature or inefficient investment.
Decentralised System Resilience (Phase 2)
This project constitutes a research study investigating the opportunities for gas network infrastructure to provide resilience solutions.
Organisations are becoming more reliant on electricity just as the grid decentralises driving a growing need for stronger resilience against power outages. High profile outages such as those seen around Heathrow Airport and across Spain and Portugal in 2025 have brought the need for additional resilience solutions sharply into focus.
By engaging end users DNOs and other stakeholders this programme will quantify the UK’s resilience challenge build the evidence base and determine whether there are opportunities for gas to play an additional role in providing resilience.
BioFlex
This project constitutes a focused feasibility assessment of local biomethane market models with the objective of determining how decentralised commercial arrangements can enable increased participation from small-scale and community anaerobic digestion (AD) producers. The study will examine commercial structures regulatory considerations and stakeholder readiness associated with enabling localised trading of green gas through existing distribution networks. It will assess the interaction between market design connection approaches and consumer engagement to identify viable pathways for implementation and scale-up.
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.
Futures Close Heat Programme (FC Heat)
To reach our national net zero targets by 2050 we need to decarbonise approximately 25 million homes in England. Domestic heating accounts for approximately 14% of the UKs entire emissions and significant investment is required to improve the energy efficiency of our housing stock. In addition there are major challenges associated with domestic decarbonisation:
- England has the most diverse housing stock in the UK. with 35% built before the end of WWII.
- Sixty-four percent are owner-occupied and these homeowners need to have a good cost effective and efficient experience of home and heating upgrade as we move towards zero carbon homes.
- Implementing heating upgrades to this ageing housing stock requires a ‘whole house’ approach therefore consideration must be given to the building fabric and heating system.
Retrofitting existing homes with electric heating systems or deployment of green hydrogen boilers offer potential solutions however the intricacies of deployment and installation are complex further research and development is required to learn more about installation performance of various heating options. Doing so will inform future domestic decarbonisation strategies.
Digestate Management
This project constitutes a UK-wide strategic assessment of digestate production arising from projected biomethane growth including quantification of volumes in 2030 2040 and 2050 and analysis of nutrient composition (nitrogen phosphorus and potassium). Sustainable land-spreading capacity will be evaluated under current regulatory constraints with regional nutrient imbalances mapped. Export potential and post-processing technologies will be assessed to determine infrastructure needs and optimal management pathways. Findings will inform how digestate management can best support sustainable biomethane growth.
Hydrogen Transition Pathways for Industrial Clusters
Hydrogen Transition Pathways for Industrial Clusters (HTPIC) is a six-month evidence led research and decision support project developed in response to the EIC’s call for innovation on the energy transition of industrial clusters. The project addresses the challenge of determining where how and under what conditions hydrogen should play a role in decarbonising industrial clusters and surrounding communities alongside credible alternative pathways.
Across the GB energy system existing hydrogen programmes and studies are typically undertaken on a cluster-by-cluster or project-specific basis using differing assumptions scenarios and decision criteria. This makes it difficult for networks and policymakers to compare options consistently understand system level trade-offs or prioritise investment in a transparent and auditable way. The absence of a common decision framework increases the risk of misaligned investment stranded assets and inconsistent outcomes across regions.
HTPIC aims to close this gap by providing NGN Future Energy Networks (FEN) and Xoserve with a structured repeatable decision framework that enables consistent evidence-based comparison of hydrogen pathways across industrial clusters. The project integrates technical economic social and deliverability considerations within a multi-criteria decision-making (MCDM) framework allowing complex evidence to be translated into clear and practical insights rather than standalone studies or narrative recommendations.
The project will be delivered in three stages:
- Stage 1 establishes a robust evidence baseline including a comprehensive literature and evidence review documented assumptions register and confirmation of scope and clusters.
- Stage 2 generates robust comparable evidence across clusters through four analytical workstreams covering hydrogen supply and demand gas coexistence and system configuration conversion practicality and costs and just-transition considerations while developing and calibrating the MCDM framework with stakeholders.
- Stage 3 applies the agreed framework to undertake structured optioneering and scenario analysis resulting in prioritised pathways cluster-specific conversion playbooks and decision-ready outputs.
Key outputs include:
- a literature and evidence review with a transparent assumption register;
- a defensible options-rationalisation matrix and MCDM framework;
- a comprehensive report addressing the four research questions set out in the EIC brief supported by an executive summary and cluster-specific annexes;
- cluster-level conversion playbooks translating analysis into practical location-specific insights;
- pathway roadmaps to 2050; and
- a final dissemination pack to support knowledge sharing across NGN FEN Xoserve and Ofgem audiences .
HTPIC will support improved strategic planning for hydrogen and alternative decarbonisation pathways reduce the risk of misaligned investment and stranded assets through structured prioritisation and strengthen alignment between industrial cluster ambitions and network development plans. By providing a transparent and consistent decision framework the project enables clearer sequencing of pathways more robust comparison of hydrogen and alternative options and improved confidence in future investment appraisal.
The project will also enhance understanding of affordability workforce implications and wider community impacts ensuring that pathway selection considers both technical feasibility and socio-economic factors. Through its systematic assessment of coexistence conversion practicality and deliverability HTPIC supports safer and more coordinated progression into downstream engineering and delivery programmes.
HTPIC will generate new system-level learning on hydrogen coexistence conversion practicality and community impacts presented through a structured scenario-based and weighted decision framework that enables transparent comparison across industrial clusters. This learning will strengthen evidence-based decision making across networks and provide a clearer foundation for future programme development regulatory engagement and investment planning.
Learning will be disseminated through the dissemination event final report executive summary and EIC knowledge-sharing channels supporting wider GB network benefit.
The project commences at TRL 2 where the structured assessment methodology and decision framework are defined conceptually. Over the course of delivery the framework will be applied across multiple industrial clusters tested against real-world scenarios and stakeholder calibration and analytically validated through structured optioneering.
By project close the solution will have progressed to TRL 3 with the methodology demonstrated and validated in a decision-support context delivering robust prioritisation and clearly articulated pathways.
The project does not include detailed engineering design trials or implementation. Early-stage engineering validation or delivery programmes across industrial clusters are already underway or in development through separate governance funding and procurement routes. HTPIC is designed to strengthen and rationalise those activities by providing a structured evidence base and decision framework to support confident downstream investment and engineering decisions.
Internal Stress Corrosion Cracking (ISCC) Pipeline Screening Tool
Being able to repurpose transmission assets for use with hydrogen and hydrogen blends can create a reliable and affordable option for decarbonising the UK and achieving Net Zero by 2050. A reliable and affordable energy system is needed to create “a fair affordable and inclusive transition to low carbon energy” (OFGEM) for all consumers (vulnerable or otherwise).
ISCC is potentially a major risk to the integrity of high-pressure pipelines repurposed for hydrogen blends. A means of assessing the risk is required as part of a pipeline integrity management system. This project aims to develop a clear risk assessment methodology which updates and enhances the methodology under NIA_NGGD0008. The methodology will then be deployed and tested across the Cadent LTS pipeline network with physical inspections being carried out on locations with high risk of ISCC.
Low Carbon Conversion of Non Domestic Properties Utilising Distributed Natural Gas
This project investigates the technical and economic feasibility of converting non-domestic buildings from natural gas to low carbon energy sources specifically hydrogen and electricity. It aims to address the significant evidence gap around the conversion of commercial and institutional buildings that are currently supplied by the GB gas distribution networks. The study will assess a wide range of building archetypes including care homes schools hospitality venues and light industrial sites using a combination of literature review site surveys detailed system designs and technoeconomic modelling. The outputs will inform future energy policy support infrastructure planning and help ensure safe and cost-effective deployment of low carbon technologies in non-domestic settings.
HyNTS Corrosion
The National Transmission System (NTS) pipelines employ a number of external corrosion barrier coatings primarily coal tar enamel and fusion bonded epoxy (FBE). Cathodic protection is deployed on the network to mitigate for coating failure. Additionally there are a range of pipeline steels that are used in both above ground buried pipework both stainless and carbon steels of various grades.
Following the previous NIA project: Research the Impact of Hydrogen on CP & Degradation of Coatings (NIA NGGT0191) the HSE have recommended follow-on testing to fully explore the impact of hydrogen permeation through steel pipelines on corrosion protection systems.
Additionally the impact of hydrogen on all credible pipeline corrosion mechanisms is to be considered to understand whether current assumptions with regards corrosion rates are valid for hydrogen pipelines.
Variable Blends Operational
National Gas Transmission are working to decarbonise the gas grid by transporting hydrogen rather than natural gas. Blending hydrogen with natural gas provides a stepping stone towards this goal fostering the hydrogen economy whilst also benefiting from up to 7% carbon savings from a respective 20% hydrogen blend.
The UK government supports blending up to 20% hydrogen by volume into the gas distribution networks and there are ongoing trials and assessments into proving the safety and technical feasibility of hydrogen blending across all networks and pressure tiers in the UK. It is anticipated 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. This is largely due to few modifications being required to accommodate low hydrogen blend percentages on the NTS.
Additionally NTS level hydrogen blending is likely to develop in phases of hydrogen blend percentage entering the network due to the hydrogen supply in the UK developing gradually over time. 2% hydrogen on the NTS equates to approximately 5TWh of hydrogen production therefore increasing this percentage will require time.
Variability in the gas blends of the network is likely due to the production of hydrogen gradually increasing over time and injection of that hydrogen being geographically spread across the network. There is also potential that hydrogen supply can vary based on factors such as production methods direct demand off takers and availability. Therefore it is important to understand the implications of blended hydrogen and natural gas at variable levels between 0-5% hydrogen and 0-20% hydrogen blend.
Hydrogen blend variability encompasses a range of factors that need to be carefully managed to ensure a successful transition to a hydrogen-integrated energy system. Understanding the impact to stakeholders such as current customers and interconnecting countries will be crucial to successfully transitioning to a blended network and identifying ways to mitigate any risks and make sure National Gas are aligned to support our stakeholders needs where possible. There is also a need to evidence the impacts and any associated changes to risks from a whole system management perspective and to research the impact of blend variability on compressor train machinery assets.
Hydrogen AGI Pipework Integrity Monitoring Phase 2
This project proposes a structured approach to assess the integrity of AGI pipework for hydrogen service. It includes development of a screening tool based on representative AGI archetypes execution of ECAs to define flaw tolerances and inspection intervals and evaluation of NDT capabilities with respect to desired AGI performances. The project also reviews integrity management software to support increased digitalisation and monitors emerging technologies for hydrogen-related NDT developments.
Pipeline Installation Techniques for Net Zero
This RIIO-2 NIA project is a desktop research study designed to support the transition of the National Transmission System to hydrogen and carbon dioxide. It evaluates construction commissioning procurement and connection challenges and identifies scalable standardisable solutions to support future Net Zero pipeline delivery.
Net Zero Safety & Ignition Risk
National Gas Transmission (NGT) owns and operates the UK’s extensive National Transmission System (NTS) which spans over 7600 kilometres and plays a vital role in delivering energy security and supporting decarbonisation initiatives. NGT has made a commitment to develop plans to transition some of the NTS to blended hydrogen operation as part of the Government’s Net Zero targets. A programme called Project Union is being developed to spearhead the NTS conversion strategy as part of the decarbonisation effort. This will further aid the net-zero target by eliminating emissions generated from managing and operating the transmission system. The Gas Distribution Networks (GDNs) and NGT have been making strides in the last decade through research physical testing etc to qualify hydrogen as a fuel within the NTS.
Hydrogen is a promising alternative fuel due to its potential to significantly reduce greenhouse emissions; however its properties present unique safety challenges. It has a much lower ignition energy (0.016mJ) when compared to Natural Gas making it more susceptible to ignition from a variety of sources along with much more devastating effects if ignition occurs.
An area of consideration for safe hydrogen operation is the ignition risk of hydrogen. This risk will span daily operations maintenance tasks compression and transport etc. Ignition risk needs to be meticulously investigated to ensure National Gas are aware of all the possible ignition mechanisms sources likelihood safeguards and mitigations etc. to ensure safe utilisation of hydrogen on the network.
This work will provide a comprehensive understanding of hydrogen ignition risks on the network with safeguards and mitigations to bring the risk of ignition into the ‘Tolerable if ALARP’ or ‘Broadly Acceptable’ levels.
TD2 Hydrogen Update
External DNV - £247365
External IGEM - £10000
Internal - £64635
£322000
Net Zero Impact on Wider Network Contents
This project aims to explore the impact of hydrogen blends (in natural gas) 100% hydrogen and carbon dioxide on contaminants (arisings) likely to be found in gas transmission pipelines (e.g. Naturally Occurring Radioactive Materials (NORMs) dusts mill scale welding slag glycols water BTEX methanol heavy metals sulphur compounds pyrophorics as well as rotating machinery lube/seal oils and valve sealants etc).
The project will aim to understand the current composition and characteristics of any contaminants the impact of hydrogen and carbon dioxide on the behaviour/composition/presence of contaminants establish how long methane related contaminants will persist on the network (for repurposed pipelines) the potential for contaminants to cause pipeline gas to go ‘off-spec’ and the implications of contaminant interactions on National Transmission System (NTS) operation/integrity.
Equations of State for Net Zero Gases
In metering applications Equations of State (EoS) are mathematical models that are used to convert measured volumes to standard units. This enables transfer from volume to mass allowing customers to be billed and for the networked to be balanced in energy. Metering and network balancing cannot be performed in volume as it doesn’t account for relative varying gas component concentrations – and therefore CV.
The EoS currently used (AGA8) is acceptable for up to 5% hydrogen but after this point it’s uncertainty is unknown – meaning the network may be unable to maintain accurate billing or system balancing. This project will obtain experimental data for a range of net zero gases and compare the output of several EoS for accuracy against real measured NTS-representative conditions.
Clean Power Flexibility Investigation
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.
Hydrogen device trials
In order to support UK ambitions for hydrogen blending and the development of a hydrogen economy National Gas will need to install new gas chromatographs with the capability to measure hydrogen up to 20% in a natural gas blend. At present hydrogen is not measured anywhere on the National Transmission System (NTS) and therefore there are no proven in-use devices and limited experience within the company to allow effective decision making in deploying these assets in the move towards net zero.
In order to make informed decisions ahead of chromatograph fleet upgrade and to allow for a wide selection of reliable device choices when it comes to that upgrade National Gas require the testing of available devices to analyse their performance and thus suitability for NTS installation. This project will employ a trusted testing house to obtain (through loaning) blend-ready chromatographs from suppliers and then to rigorously examine the performance of those devices. These devices could be tested at the testing house’s site or at the instrument vendor’s site.
Integrity Management of Carbon Dioxide Pipelines
Existing defect methodologies are aligned with the management procedures and are adopted to inspect assess and repair the pipelines for defects and take suitable measures to reduce them. However the applicability of these techniques in the presence of gaseous phase Carbon Dioxide remains uncertain. The project will identify relevant defect types which may be encountered and considered hazardous in the presence of carbon dioxide study the impact of gaseous phase carbon dioxide and corrosion has on them assess whether the failure mechanism has changed after introducing carbon dioxide and recommend inspection assessment and repair approaches. Additionally the project will capture the extent of repairs across the NTS and assess the impact of implementation of the recommended gaseous phase carbon dioxide inspection assessment and mitigation technologies in terms of safety and useability.
Hydrogen Impact on NTS Welds
This project investigates how hydrogen affects the integrity of welded joints (seam welds and girth welds) in the UK National Transmission System (NTS) pipelines as part of plans to repurpose existing natural gas infrastructure for hydrogen transport.
Specifically Work Package 4 integrates results from metallurgical characterisation historical weld procedures and fracture toughness testing conducted in high-pressure hydrogen. The study examines pipeline steels of different grades and vintages (including X46 X52 X60 X65 and X80) focusing on weld metal and heat-affected zones (HAZ) which are known to be the most vulnerable regions.
The report combines:
- Detailed metallography and hardness mapping of real NTS welds
- Post-test fractographic analysis of specimens tested in hydrogen
- Interpretation of fracture toughness data
- An overall assessment of risks and uncertainties associated with hydrogen service
- Recommendations to support safe decision-making for hydrogen repurposing.
High Pressure Venting and Flaring Demonstration for Net-Zero Gases Transportation
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 asset 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.
Fatigue Rig Post Test Inspection and Mechanical Testing of Hydrogen Charged Materials
High pressure steel pipelines are essential in enabling a safe natural gas transportation network an overly engineered solution tried and tested over several decades proving the NTS to be a robust nationwide asset. The National Transmission System is used to flow gas every day to keep the lights on and our homes heated by connecting large scale industry cities and towns where the network is dynamic allowing for flexibility and adaptability to various flow demand scenarios. This is done so by utilising over 5000 miles of varying grades and differing sizes of pipelines where the gas can flow build line pack for high energy demand areas and provide a mass energy storage solution.
The NTS is used to limit gas loss manage flow direction facilitate maintenance repair modification testing and commissioning to enable safe and effective start-up and shutdown of our pipelines. We now must further evidence pipeline steel material integrity when subjected to high pressure hydrogen gas this can be done by expanding upon the existing fatigue rig standalone testing at DNV Spadeadam.
Although some pipelines materials that we use today have seen blends and 100% hydrogen within the HYNTS Phase 1 test facility what we have not done is post hydrogen fatigue cycling non destructive testing of materials that have been subject to prolonged high pressure hydrogen. One of the welds that make up the fatigue rig has a known weld defect within it NGT aims to have the welds and the weld defect analysed through various methods of testing such as magnetic particle inspection followed by if necessary standard ultrasonic testing.
In 2022 small scale mechanical characteristic tests were conducted to characterise the mechanical properties of the materials used within the construction of the fatigue rig this testing commenced outputting a standard mechanical property data set the new end of test data post hydrogen exposure will be compared to the original data set from 2022 at the end of fatigue cycling. Testing will establish the effect of trapped hydrogen on ‘standard’ mechanical properties measured To facilitate this DNV will remove all girth welds selected seam welds and fitting welds and store them at low temperature to mitigate loss of hydrogen from within the trap sites..
A technical note will be prepared comparing the results of the weld inspections (internal and external inspections). The note will be used to confirm defect removal for metallographic examination.
A technical report will be prepared summarising the macro and microscopic examinations undertaken confirming defect size (to that reported by UT) and whether the defect was an original feature else created due to the pressure cycle duty of the test vessel and the hydrogen environment.
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.
Carbon Dioxide Repurposing Procedure for the NTS
The project described in this FEN report 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.
Innovative approach to Policy document management
As part of National Gas’s Three Molecule strategy the technical evidence for the transportation of hydrogen and carbon dioxide through the National Transmission system is being gathered through the HyNTS and CO2 programmes. This technical evidence will feed into the updates of NGT’s suite of policies and procedures which are used to demonstrate compliance with the Gas Safety (Management) Regulations (GSMR) Pipeline Safety Regulations (PSR) and Pressure System Safety Regulations (PSSR).
This project will develop the approaches to compliance with regulations for hydrogen hydrogen blends and CO2 considering both new build and repurposed assets. The project will also define how the NTS Safety Case of the future will look including modular design and digitalisation to streamline access to information.
Predictive Model for Flood Risk Management
This project developed and evaluated 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 was deployed at Goxhill AGI Crieff AGI Hatton Compressor Station and Penicuik Peat Farm pipeline following a a nationwide flood risk survey. The trial assessed 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 concluded with a technical report and recommendations for wider rollout under RIIO-3.
Standardised Biomethane Connections
Through consultation with the biomethane industry National Gas are looking to offer a cost effective repeatable and simplified Minimum Connection arrangement at greenfield locations with low visual impact by locating the network isolation valves in a pit. Thus avoiding a traditional larger Above Ground Installation with perimeter security fence and internal vehicle access and potential local authority planning permission.
The use of pits to house valves on National Gas AGI’s has historically created operational and maintenance issues such as pipe pit wall transition corrosion pit flooding and access restrictions.
However through consultation with NG Chief Engineer a decision support paper was submitted and approved allowing the development of a valve pit arrangement to align with requests from the biomethane industry and address historic issues.
Following this decision conceptual designs were completed for minimum connections at Oulton Airfield and Manby projects in 2024. These designs included a concept design of a MOC valve arrangement in a pit.
Recompression Solutions for a Net Zero NTS
This project will provide National Gas Transmission (NGT) with a clear technical understanding and strategy for the deployment of recompression solutions for Net Zero gas networks including hydrogen blends 100% hydrogen and Carbon Dioxide transmission.
The NIA Safe Venting & Recompression of Hydrogen innovation project explored the possibility of repurposing natural gas recompression units for hydrogen blends and 100% hydrogen and investigated new solutions for hydrogen pipeline recompression as part of routine maintenance activities.
This project furthered NGT’s knowledge of hydrogen recompression for different scales and applications on the NTS to reduce venting and explore similar solutions for carbon dioxide pipelines.
Deblending Rollout Strategy Phase 2
National Gas Transmission (NGT) are committed to reducing emissions from the operation of the National Transmission System (NTS) and eliminating emissions by 2050. The transition to hydrogen provides an opportunity to reduce carbon and utilise the network for hydrogen refuelling for transport. The HyNTS Deblending for Hydrogen Transport project has involved the development of a UK-wide rollout strategy from ERM that lays out demand clustering and potential locations for deblending supplied refuelling for transportation mapped against the NTS.
The project will aims to obtain further information on NRMM maritime cars LGVs and mobile power to fully understand the hydrogen demand. It will also review the existing rollout strategy to ensure it is accurate and full captures the current hydrogen market given the changes in this landscape
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
Hydrogen backbone social economic assessment
Develop credible and independently modelled pathways to test the economic case of developing a H₂ Backbone and prepare NGT for dialogue with NESO DESNZ HMT and a wider group of stakeholders.
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.
PE Service Pipe Disconnection
The PE Service Pipe disconnection development project aims to produce a product and technique which can safely successfully and efficiently disconnect PE Service Pipes from an external Emergency Control Valve (ECV) following meter removal. This solution aims to prevent the inconvenience risks and additional costs associated with traditional excavation methods.
Suitability of 17-4 PH Stainless Steel Gas Components
The transition from natural gas to hydrogen introduces new material challenges within the context of the GB gas network. One critical concern is hydrogen embrittlement particularly in 17-4 Precipitation Hardened (PH) Stainless Steel commonly used in axial flow regulators and other key gas network components like valve stems. Hydrogen embrittlement can significantly reduce ductility fatigue life and fracture toughness potentially leading to component failure. While research exists much of it focuses on extreme conditions (e.g. high pressures and rapid temperature cycling) that do not reflect typical operational environments in the GB gas network.
This project will look to combine industry knowledge literature review and empirical testing to address these outstanding challenges.
GGT- Novel Green Gases
Novel green molecules have the potential to make a significant contribution to the decarbonisation of the UK’s gas network while also reducing system costs. Synthetic and e-methane can play a significant role in meeting future industrial demand as well as decarbonising the power transport and domestic heat sectors. This project investigates novel green gases in more depth to understand how they can be implemented effectively and quickly deployed to decarbonise the gas sector in the UK.
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.
Co2 Capture and Methanation Feasibility Study
The project focuses on exploring practical and innovative pathways for CO₂ utilisation with the goal of supporting scalable and cost-effective carbon management solutions. It examines a range of technologies market mechanisms and regional integration opportunities to better understand how captured CO₂ can be effectively reused. A key emphasis is placed on evaluating the economic feasibility of utilisation particularly through methanation including the potential commercial value of CO₂ and e-methane. The study combines technical and economic analysis with a case study of a methanation plant while also assessing local CO₂ markets and potential sales opportunities. The project also addresses key risks such as technology uncertainty hydrogen pricing and market volatility. Overall it aims to de-risk investment and stimulate the development of the CO₂ utilisation market from the AD sector.
This study assesses the available pathways to recover and monetise the biogenic CO₂ stream produced during biogas upgrading at UK anaerobic digestion (AD) plants with a particular focus on using it to produce synthetic natural gas (SNG). The study begins with extensive stakeholder and technology vendor engagement to identify suitable CO₂ sources potential utilisation pathways market opportunities and technology options.
A central element of the study is the development of a detailed methanation case study based on the capture of approximately 500 Nm³/h of biogenic CO₂ and the conversion of this CO₂ into e-methane using low-carbon hydrogen. Feasibility-level engineering will be completed for both the carbon capture and methanation facilities including process modelling mass and energy balances block flow diagrams preliminary process flow diagrams equipment sizing site layouts and Class 5 capital cost estimates supported by vendor data. These engineering outputs will underpin a detailed economic assessment examining the impact of key variables such as hydrogen cost electricity prices CO₂ value carbon credits and certificate revenues on the levelized cost of e-methane production. The study also includes a local CO₂ market assessment a review of by-product utilisation opportunities such as reaction water and waste heat recovery and the development of a roadmap outlining the steps.