Net zero and the energy system transition
Hydrogen & Carbon Dryness Management
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):
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.
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.
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.
Network Policies and Procedures – Development Roadmap
UK gas networks are managed and maintained using an extensive suite of policies policies standards and procedures. These documents have been developed gradually over decades of gas network operation however the transition to hydrogen necessitates a wholesale review and update of all existing documents. There is much commonality between the networks’ documents and therefore it would be most efficient to update these documents in a coordinated way to avoid the unnecessary duplication of effort.
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.
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.
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.
NextGen Electrolysis – Wastewater to Green Hydrogen Beta
Wales and West Utilities are partnering with HydroStar Welsh Water and NGED to look at two demonstrator projects required from new electrolyser systems and the associated electrolyte that ensures resilience of hydrogen supply across the network giving best value for money and energy security within WWU’s network along with other UK wide Gas Distribution Network (GDN) customers.
Current electrolysers focus on stack-efficiency and hydrogen purity without considering real-world manufacturing and operational constraints and the high costs associated. This project focusses on utilising impurified-water e.g. rainwater storm-overflow and industrial process wastewater as feedstock which reduces operational constraints and costs for customers whilst enabling wide-scale uptake of low-carbon hydrogen.
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Gas Network Evolution Simulator (Alpha)
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.
Hydrogen Ignition Risk from Static & Autoignition – Stage 2B
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.
Human Behaviours and automation
This project will produce valuable insights into understanding the relationship between human behaviours and the utilisation of safety devices with automated functionality. This follows the work done on hydrogen risk mitigations which included technology such as hydrogen detectors with automated functionality to remotely notify the emergency call centre to dispatch an engineer to the detected leak. In their review of this work HSE have asked if the assumption that consumers will continue to act the same knowing the device will be doing some automated will change the validity of the modelling assumptions. This project will address that query and build on our own understanding of consumer insights; something which could add a depth of value to other projects exploring automated safety systems.
Asset Compatibility Assessment Tool for Transmission
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.
Renewable Energy Harvest (Discovery)
Renewable Energy Harvest unlocks the untapped power of Britain’s countryside by turning farm food and forestry residues into clean flexible green gas. By combining biomethane and syngas production with advanced mapping and forecasting tools the project will identify where rural resources can best connect into the gas network. This innovation supports a fair low-carbon transition - cutting emissions reducing costs and keeping energy value in local communities. Backed by Northern Gas Networks and partners Renewable Energy Harvest paves the way for smarter more resilient infrastructure that helps Britain make better use of low-carbon gases for a decarbonised future energy system.
Delocalised Hydrogen Storage
Historically decentralised low-pressure gas storage such as gas holders have been used to balance gas network supply and demand. This project will explore how a similar approach can support hydrogen rollout particularly in urban and industrial environments where pipeline line-pack alone may not provide sufficient flexibility.
Network Classifier
This project will develop a hydrogen‑specific risk‑based gas escape classification system for WWU by reviewing existing standards and methodologies modelling hydrogen leak behaviour conducting field trials and developing a final operational tool and updated procedures. The project adapts natural gas escape management processes for use on 100% hydrogen networks by analysing gaps in current practice validating real‑world behaviour through targeted trials and producing training documentation and decision‑support tools.
OptiStore
The OptiSTORE project seeks to address the challenge of supply and demand imbalance within Wales & West Utilities’ (WWU) network as means to mitigate the need for storage particularly in support of Net Zero ambitions including the planning for development of new hydrogen pipelines and WWU’s existing HyLine programme.. Current geological hydrogen storage methods such as salt caverns saline aquifers and depleted oil and gas reservoirs are capital intensive often technically complex and reliant on specific geological conditions which are less present across WWU’s geography.
Whilst hydrogen can be stored as a liquid this process requires extremely low temperatures which is technically complex and costly due to the energy required to maintain such low temperatures. One promising alternative to this is Ammonia which is attractive due to its lower storage temperature (-33°C versus -253°C for hydrogen) higher volumetric energy density and existing infrastructure and regulatory familiarity.
This project will explore the feasibility of using ammonia as a means to provide supply-side flexibility of hydrogen to support industrial clusters and future hydrogen pipeline developments.
H2 Power – Whole System Implications
This project assesses the role of hydrogen‑to‑power (H2P) generation within WWU’s planned hydrogen network. It identifies maps and evaluates potential H2P assets; develops hydrogen demand scenarios; assesses commercial and policy risks; and prepares cost‑benefit analysis (CBA) case studies to inform decision‑making. The outcome will be a fully integrated whole‑system assessment enabling WWU to understand risks opportunities and required policy frameworks for incorporating H2P into regional hydrogen infrastructure.
Lined Rock Caverns for Flexible Hydrogen Storage – Phase 2
This project advances lined rock caverns (LRCs) as a flexible hydrogen storage solution in WWU’s area by moving from regional screening to site‑specific pre‑feasibility. It refines geology and site availability shortlists candidate sites in South Wales and South West England conducts a detailed pre‑feasibility study with borehole core analysis at a priority site and assesses commercial models and funding routes culminating in a final report to inform decisions on progressing to full feasibility.
Hydrogen Ignition Risk from Static and Autoignition (HIRSA) – Stage 3
The HIRSA programme is assessing ignition risks for the transition to hydrogen with Stage 3 focusing on high pressure risks including shockwave ignition and rapid adiabatic compression. This research supports the safe integration of hydrogen into gas networks.
Hydrogen Storage Feasibility Study – Phase 2
This assesses the suitability of WWU’s three high-pressure gas storage vessel sites (Weston-super-Mare Cheltenham and Bristol/Stapleton) as a case study where learning can be applied to relevant GB networks for hydrogen service. The work includes materials characterisation hydrogen embrittlement testing analysis of 100% hydrogen and 5%/20% hydrogen blends assessment of capacity and pressure requirements evaluation of the implications of removing the vessels entirely and down-selection of viable liner materials and application methods. The project will produce site-specific evidence a shortlist of feasible liner options and clear engineering recommendations to maintain required capacity and pressure envelopes under hydrogen scenarios.
Green Gas Gateway
Gas networks in Britain have connected 130 biomethane plants which together have capacity to produce over 11TWh of green gas – enough to meet the annual demand of around a million average homes.
As biomethane production tends to cluster in farming areas some parts of the country have higher connections and future potential. This can present challenges in relation to the capacity available for existing and new plants to inject biomethane especially when overall gas demand is lower in summer months.
The gas networks and their partners have mature systems and processes to assess capacity and work with producers and developers to identify capacity. More recently potential solutions to constraints have been developed and trialled notably through the Optinet project (NIA_CAD0061) and including Wales & West Utilities’ Smart Pressure Control roll out and Reverse Compression.
The Government is continuing to support new production through the Green Gas Support Scheme and is considering future policy for biomethane. This could significantly increase the volume of biomethane produced and connected which has been recognised in NESO’s FES 2025.
In its Draft Determination for RIIO-3 Ofgem has recognised the potential for future growth in biomethane connections. The regulator “encourage[s] the GDNs to collectively engage with the biomethane industry to streamline and align connection processes”.
In response to this and other feedback from biomethane developers and operators this project will explore the potential for more standardised approaches to support capacity for biomethane and overcome constraints.
Carbon Networks Phase 2
The UK Government has identified Carbon Capture Utilisation and Storage (CCUS) as a critical enabler of industrial decarbonisation committing £20 billion to early deployment and targeting 20-30 MtCO₂ stored annually by 2030. Much of the UK’s industrial emissions are geographically concentrated opening the door to targeted CCUS clusters that can deliver outsized impact. GDNs are well positioned to play a meaningful role in this emerging ecosystem.
In Carbon Networks Phase 1 Blunomy assessed the strategic fit between CCUS and the GDN business model. The study identified a range of potential roles including local CO₂ collection participation in transport and storage networks and support for blue hydrogen and CO₂ utilisation initiatives – and it highlighted the importance of early positioning to shape regulatory and commercial pathways.
Phase 2 aims to build on this foundation and move from conceptual framing to actionable insight. Blunomy in the next stage will explore specific industrial opportunities within SGN’s and WWU’s footprint engage with project developers and clusters and outline potential pilot activities. Alongside this the work will assess how CCUS participation aligns with SGN’s broader priorities and the implications for regulatory engagement and investment planning.