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Net Zero Safety & Ignition Risk
National Gas are investigating the use of the National Transmission System to transport hydrogen and hydrogen blends. To support this research and testing is required to understand the risks of high pressure hydrogen transmission including ignition. This project will identify for 100% hydrogen and blends of hydrogen up to 20% the sources of ignition including how the distance of ignition sources affects the likelihood of ignition. It will also investigate the frequency and the different types of ignition events e.g. jet fires. Lastly it will look at the probability of ignition on sites and in pipework.
Hydrogen Impact on NTS Welds
Laboratory and full-scale testing have demonstrated that hydrogen gas affects the fracture performance of pipeline steel welds. To avoid severe knockdown factors stipulated by existing hydrogen pipeline codes mechanical property data from welds tested in high-pressure gaseous hydrogen is required to enable optimised operation of the NTS in hydrogen.
National Gas Transmission have conducted a series of fracture toughness and fatigue crack growth rate tests on a wide selection of pipeline steels and welds representative of those used on the National Transmission System (NTS). A thorough review of the welds tested and how these compare to the wider population of welds in service on the NTS is required to provide further confidence to use this data in pipeline repurposing assessments and for new build design.
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.
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 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.
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.
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.
H2 Housing Design
This project will explore ventilation and explosion relief requirements for housing currently used on the gas network for pressure regulating installations (PRIs). Housings currently provide security from a range of factors from weather to vandalism while also providing the necessary relief requirements in the event of an emergency. The understanding of these requirements for Natural Gas has been developed however work conducted in the IGEM TD/13 hydrogen supplement did not fully address whether these design specifications are suitable for use with Hydrogen. This multi-stage project will first explore the design specifications listed in industry standards (IGEM/TD/13 GIS/PRS/35 SGN/SP/CE/10 etc) and understand which of these may be appropriate and which may require redesign. The latter stage of this project will take the design specifications deemed to be unsuitable for use with hydrogen and conduct testing to develop revised design specifications which would provide the necessary relief requirements.
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.
Hydrogen Ignition Risk from Static and Autoignition Stage 2B – Static Generation experimentation
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.
Hydrogen Permeation through the Oxide Layer Phase 1
This project is looking to address uncertainties surrounding LTS pipeline materials by investigating the effect of the oxide layer on hydrogen permeation rate for steel pipelines. This project will also investigate the formation of an oxide layer inside the pipe at different temperatures as well as how the microstructure of the pipeline steel and condition of the oxide layer affect permeation for different grades of steel. It is critical this relation is better understood as these uncertainties are currently hindering our ability to fully and accurately assess the repurposing of the LTS. The outcomes of this project have the potential to increase cost-savings and improve confidence in the existing network to carry hydrogen including blends.
Domestic Air Ingress Mitigations
This project will help to provide assurance to UK Gas Distribution Network Operators (GDNOs) and wider industry on the safe design of domestic gas appliances in a future where hydrogen is being distributed in network pipelines. A risk to the normal safe operation of appliances under 100% hydrogen operation exists where a flammable hydrogen/air mixture is supplied to the appliance creating the potential for flashback to occur within the gas installation pipework. This work will provide assurance that domestic appliances designed to operate on 100% hydrogen are designed in a way which do not enable flashback to occur.
The project will also investigate the long-term feasibility of installing an auto-locking Emergency Control Valve (ECV) at the end of 100% hydrogen networks to ensure that any reinstatement of supply after a period of isolation can only be undertaken by a competent gas engineer.
Effects of Water Ingress in a Hydrogen Network
Wales & West Utilities is undertaking a major programme of change to support decarbonisation and deliver a Net Zero gas network. The primary objective of this project is to investigate the effects of water ingress within a 100% hydrogen network and a blended hydrogen/natural gas network. The goal is to determine whether the introduction of hydrogen into the gas network could cause any additional impacts when water ingress occurs and to compare these effects to those observed in the current natural gas network.
Flexible Gas Transition Plant – Phase 1 Feasibility Study
Analysis of the distribution networks undertaken in the H2 Caledonia and H2 Connect projects has identified sectorisation isolation as the optimal approach for conversion. Sectorisation isolation allows for a sector-by-sector approach ensuring the gradual conversion of existing Natural Gas connections over to hydrogen or managing the disconnection process should customers opt for alternative heating solutions. This project will aim to develop an understanding of the technical and financial feasibility of a Flexible Gas Transition Plant (FGTP) through primary project outputs such as: outline of design options development of a list of transition use cases a cost benefit analysis (CBA) for each transition scenario and a roadmap for future phases including prototype design and trials.