Future Energy Networks

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.

High pressure steel pipelines are essential in enabling a safe natural gas transportation network, an overly engineered solution tried and tested over several decades, proving the NTS to be a robust nationwide asset. The National Transmission System is used to flow gas every day to keep the lights on and our homes heated by connecting large scale industry, cities and towns where the network is dynamic allowing for flexibility and adaptability to various flow demand scenarios. This is done so by utilising over 5000 miles of varying grades and differing sizes of pipelines, where the gas can flow, build line pack for high energy demand areas and provide a mass energy storage solution.

The NTS is used to limit gas loss, manage flow direction, facilitate maintenance, repair, modification, testing and commissioning to enable safe and effective start-up and shutdown of our pipelines. We now must further evidence pipeline steel material integrity when subjected to high pressure hydrogen gas, this can be done by expanding upon the existing fatigue rig standalone testing at DNV Spadeadam.

Although some pipelines materials that we use today have seen blends and 100% hydrogen within the HYNTS Phase 1 test facility, what we have not done, is post hydrogen fatigue cycling non destructive testing of materials that have been subject to prolonged high pressure hydrogen. One of the welds that make up the fatigue rig has a known weld defect within it, NGT aims to have the welds and the weld defect analysed through various methods of testing such as magnetic particle inspection followed by if necessary standard ultrasonic testing.

In 2022 small scale mechanical characteristic tests were conducted to characterise the mechanical properties of the materials used within the construction of the fatigue rig, this testing commenced outputting a standard mechanical property data set, the new end of test data post hydrogen exposure will be compared to the original data set from 2022 at the end of fatigue cycling. Testing will establish the effect of trapped hydrogen on ‘standard’ mechanical properties measured, To facilitate this, DNV will remove all girth welds, selected seam welds and fitting welds, and store them at low temperature to mitigate loss of hydrogen from within the trap sites..

A technical note will be prepared comparing the results of the weld inspections (internal and external inspections). The note will be used to confirm defect removal for metallographic examination.

A technical report will be prepared, summarising the macro and microscopic examinations undertaken, confirming defect size (to that reported by UT) and whether the defect was an original feature else created due to the pressure cycle duty of the test vessel and the hydrogen environment.

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.

Following the work completed on the policies and procedures project by QEMS, WWU have identified the requirement to update and re-vamp the existing Safe control of operations (SCO) procedures used by the network to support delivery of upcoming projects.

FutureGrid CO2 is the final phase of a suite of Carbon Dioxide projects, looking at how National Gas can repurpose parts of its network to transport gaseous-phase Carbon Dioxide safely. What started out as literature reviews and feasibility studies, will turn into, physical testing and demonstration. National Gas will be using its world-leading FutureGrid facility to demonstrate how Carbon Dioxide will flow through its pipes, delivering on its promise to further use this facility after our successful FutureGrid SIF Beta projects. We will also be completing carbon dioxide venting, ruptures and real-time impurity corrosion tests- all of which are underexplored.

This project aims to develop a means of forecasting gas quality at the NTS offtakes, which will support current arrangements for target Calorific Value (CV) setting, allowing networks to more accurately provide target CVs to biomethane producers and reducing sudden changes in targets sent to biomethane sites which can cause operational problems. Going forward gas quality information on CV and potentially Wobbe will also assist the GDNs in managing hydrogen blend.

The Phase 3 project on gas inhibitors for hydrogen pipelines aims to translate lab-scale findings into practical applications for the UK’s National Transmission System. It focuses on validating the effectiveness of oxygen and alternative inhibitors in mitigating hydrogen embrittlement, addressing unresolved safety and integrity concerns from previous phases, and designing a plan for safe integration into existing infrastructure. The project includes physical demonstration planning, and network design to assess technology implementation.

This project will entail a feasibility study to assess the viability of developing a secure, scalable, and interoperable data sharing infrastructure for National Gas Transmission (NGT), supporting regulatory compliance, stakeholder access, and alignment with NESO’s DSI initiative. The main objective is to gain a better understanding of how we share data currently and how this will change moving forward both within established participants and enabling new participants and stakeholders to benefit from National Gas’s data. This will support the wider NESO led DSI initiative. Using two NGT data systems as a use case for this study

Repurposing of natural gas pipelines made of carbon steel for use with hydrogen blends requires a fitness-for-service analysis as part of the hydrogen use safety case. Girth welds of an unknown quality exist in the Local Transmission System (LTS). In hydrogen service these welds would have a greater susceptibility to fracture failure due to material embrittlement caused by interaction of steel material with hydrogen.

Current in-line inspection methods do not routinely inspect girth welds for defects. This project aims to test the available technology for its capability to detect defects and cracks in girth welds. This will provide valuable data for engineering critical assessments required to repurpose natural gas pipelines. It will also inform about the state of art inspection techniques and whether they can be used as a tool for repurposing pipelines.

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.