Projects

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.

To achieve decarbonisation targets all gas network operators in the UK need to demonstrate that the gas network can safely technically and economically facilitate the distribution of low-carbon gases (biomethane and hydrogen). In response to this challenge SGN aim to review the feasibility of the formation of biomethane islands in their Scotland area of operation. The outputs of this project will establish a business model for the optimisation of biomethane injection and formation of biomethane islands across the UK’s gas network. A feasibility study will address key areas including regulatory technical environmental social and commercial aspects as well as comprehensively assess the viability of developing Biomethane Islands. The outcome of the feasibility study will be to inform decision-making regarding project implementation. This will be captured and delivered in a comprehensive report and financial model of the business case. These islands will serve as models for sustainable living demonstrating the feasibility and benefits of a circular economy approach to energy production and waste management and offer a low disruption option for the decarbonisation of all classes of gas consumers - Industrial Commercial and Domestic.

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.

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.

This study builds on previous technical work undertaken to support the 1 mol% oxygen Gas Safety Management Regulations (GSMR) amendment up to 38 barg. The work plan was targeted to focus on aspects that are more pertinent to the National Transmission System (NTS) including information from the current developments for European standards and supporting information from published studies on the impact of oxygen. The scope covered:

• Integrity – focusing on changes to corrosion rates and developing the understanding that increased oxygen content may have on the different factors that impact on corrosion rates.
• Measurement – considering the effect of higher oxygen content on the ability of the different analysers and equipment to measure accurately.
• Gas quality – reviewing the impact on key gas quality parameters and considering the potential impact on trace components that may be present.
• Pipeline “dryness” – investigating the impact of water dew point and water content and the effect of increased oxygen.
• Gas mixing – recognising that the flow from biomethane injection will in most cases be lower than the main pipeline flow deduce if higher oxygen content gas could be transported long distances through the pipeline network.
• Gas storage – building on available information to assess if higher oxygen content impacts on gas storage.
• Gas utilisation – identifying if there are end users that could be significantly impacted by elevated oxygen limits.
• Intermediate limits – considering if an intermediate limit would be preferential.

The scope was developed to provide technical evidence to understand the implications for the NTS recognising that this introduces additional factors that were not considered in the previous studies.

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

This project constitutes a research study investigating the opportunities for gas network infrastructure to support storage and balancing in a decentralised UK energy system. The research will consider how a decentralised system might look in the UK from now until 2030 and onto 2050. An evaluation will be made of how other countries are approaching decentralisation identifying examples the UK could draw on. Consideration will be given to how grid balancing will be achieved across various scenarios of peak demand and particular geographic locations in the UK and what challenges and opportunities this presents to gas networks.

This project will deliver a series of reports and presentations which reflect the need to minimise disruption during any conversion taking into account customer needs and the wider supply chain not just the needs of the GDN.

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.