Future Energy Networks

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.

This project will explore the feasibility of integrating hydrogen train refuelling infrastructure to support the development of a hydrogen rail network. This has particular relevance to our network as some of the UK’s hardest to electrify rail routes are situated in Wales and South West England. The project will focus on these hard to electrify routes, exploring H2’s potential role in enabling their decarbonisation. If successful, this project can help the WWU network to become a proving ground for real-world delivery of impactful H2 rail technology. It is expected to provide information which can be used in planning strategic hydrogen pipeline routes and network repurposing plans, and support regional energy planning.

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 assembles a multi-laboratory team to address high-priority research topics identified by industry related to the blending of hydrogen into the U.S. natural gas pipeline network. PRCI has been contracted by DOE to provide contract and invoicing support which allows additional members to join after project start.

There were four main activities being performed in Phase 1 of the CRADA project that fell under two categories: materials research and analysis. Sandia National Laboratories (SNL) led the materials research on metals, which is primarily used for natural gas transmission, while Pacific Northwest National Laboratory (PNNL) headed the research on polymeric materials, which comprise the natural gas distribution network. Argonne National Laboratory (ANL) was responsible for life-cycle analysis while the National Renewable Energy Laboratory (NREL) performed techno-economic analysis on hydrogen blending scenarios, the work on these subjects will be extended in Phase 2.

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.

The LTS Futures project aims to understand how the local transmission system (LTS) could be repurposed from Natural Gas to hydrogen. The project encompasses several elements which will feed into a blueprint methodology for repurposing the LTS to hydrogen. During one of the work elements, LTS Futures conducted full-scale testing of pipeline defects and small-bore connections exposed to hydrogen. Testing was conducted until failure to provide information for hydrogen pipeline design, standards, and operational procedures. This project will undertake further detailed analysis of the fracture surfaces to provide a visual confirmation of hydrogen diffusion into the pipeline microstructure and if this contributed to failure.

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.

This project will help WWU to understand considerations for 100% Hydrogen Rollout at a town scale, to inform future activity on preparation for repurposing. Areas will be chosen which are representative of different networks, housing stock and demographics, which will require different approaches and engagement.

Existing defect assessments and repair methodologies are aligned with the P/11, P/20 and PM/DAM1 management procedures and are adopted to inspect, assess and repair the pipelines for defects and take suitable measures to reduce them. However, the scope and applicability of these assessment and repair methodologies in the presence of gaseous phase carbon dioxide remain uncertain. The key challenges which the project aims to address are:

• Will existing repair techniques such as epoxy shell, welded shells, composite wraps, gouge dressing etc. be suitable for transmission of gaseous phase carbon dioxide?
• What are the different defects we may encounter or consider hazardous in the presence of carbon dioxide? What are the impacts of carbon dioxide on each defect type? And how much does water/corrosion exacerbate this?
• Have the mechanisms of failure for each defect type changed after introducing carbon dioxide?
• Can we implement the assessment 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 review the impact of carbon dioxide on the effectiveness of these inspection, assessment and mitigation technologies.