Future Energy Networks

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.

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 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.

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.

The National Transmission System (NTS) uses dry scrubbers, filters and strainers to remove contaminants in the gas stream. Introducing hydrogen raises new challenges due to its distinct properties, which could affect the performance and efficiency of these existing cleaning assets. We completed a project that investigated the compatibility of these assets with hydrogen and hydrogen blends to ensure gas quality without compromising the safety or efficiency. An outcome was to get a deeper understanding of the fracture and fatigue behaviours of these equipment to better understand whether hydrogen will impact the material properties. This assessment will undertake a targeted CTR analysis to inform a future potential physical test programme.

Project will deliver strategic analysis and recommendations to support the accelerated adoption of Hybrid Heat Systems (HHS) in GB. This includes assessing technology options, commercial models, stakeholder perspectives, and system integration pathways. The work will result in actionable insights, clear positioning of HHS within the wider decarbonisation strategy.

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.

Following the successful completion of Blending Implementation Plan (BIP) Phase 1 (Planning) in 2023 and BIP Phase 2A (Design) in 2025, the gas networks have engaged KPMG to proceed with the next phase of the programme, BIP Phase 2B (Delivery).

Running from February 2026 to November 2026, and focusing on Market Frameworks impacts, Phase 2B is required to build on the consensus achieved in Phase 2A and close out all implementation areas that require joint-decision making by the networks. These decisions pertain to detailed design of the application window and industry governance. The outcomes of Phase 2B will create a clear and consistent pathway for individual networks to support the application window and connections process, alongside addressing common areas of industry governance, based on collective decision making to meet timelines of future HAR.

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.