University of Manchester and National Grid team up to develop SF6-free retrofill solution for electricity network

National Grid and The University of Manchester are to collaborate on a four-year project to develop a full-scale demonstrator at the Deeside Centre for Innovation, designed to test at scale how the UK can retrofill SF₆ across its network of high-voltage equipment.

SF₆ is a gas commonly used in the power industry to provide electrical insulation and arc interruption. However, SF₆ is a potent greenhouse gas with a global warming potential that is 25,200 times greater than CO₂.

The £1.9m project will see experts at Manchester help determine how National Grid can develop a retrofill solution to replace SF₆ with an environmentally friendlier alternative without having to replace or otherwise modify the existing equipment.

This solution – to be demonstrated at National Grid’s test facility the Deeside Centre for Innovation – will mean National Grid can avoid the environmental impact and cost of replacing equipment otherwise fit for many more years’ service.

It is not the first time National Grid and The University of Manchester have teamed up on a project exploring SF₆ alternatives – a previous initiative which concluded in 2020 is now up for an IET Engineering & Technology magazine innovation award for ‘Best Innovation in Net Zero and Sustainability’.

In a separate pilot project last year National Grid and Hitachi Energy developed and deployed a world-first solution at Richborough substation in Kent to replace SF₆ with a greener alternative, marking a key step in National Grid’s ambition to reduce its SF₆ emissions by 50% by 2030. The new demonstrator with Manchester will explore how the retrofill solutions might be applied across more of the network.

This project will bring together the interdisciplinary expertise of Manchester’s Department of Electrical and Electronic Engineering and the Department of Chemical Engineering, led by Dr Tony Chen with Professor Philip Martin.

Together the university and National Grid will create a physical demonstration, complete with an inbuilt condition-based monitoring system, that will focus on the applicability of SF₆ retrofill techniques. It will be developed in Manchester’s High Voltage Research Laboratory, equipped with facilities that can test up to 600 kV DC, 800 kV AC, and 2 MV impulse, and has been the testbed for developing pioneering solutions such as improved designs of high voltage overhead lines and developing safer, greener high voltage transformers using ester liquid.

The project builds on Dr Tony Chen’s established expertise in SF₆, and it is anticipated its findings will give asset managers the information required for retrofilling significant quantities of SF₆-filled equipment across the transmission network, bridging the current gap between established feasibility, and long-term, real-world implementation.

Mark Waldron, Technical Lead at National Grid Electricity Transmission, said: “It’s exciting to be following the world-first SF₆ retrofill in Richborough substation with this initiative taking us a step closer to a solution to replace the gas in more of our assets. The potent combination of Manchester’s expertise in this area and the innovation and demonstration capability at our state-of-the-art Deeside facility will deepen our understanding of retrofill solutions, and could boost our progress in the decarbonisation of the grid while achieving a significant cost benefit for consumers.”

Energy is one of The University of Manchester’s five research beacons, examples of pioneering discoveries, interdisciplinary collaboration and cross-sector partnerships that are tackling some of the biggest challenges facing the planet. This project reflects the commitment of Manchester’s energy experts in delivering a just and prosperous Net Zero energy future.

By matching science and engineering, with social science, economics, politics and arts, the University’s community of 600+ experts address the entire lifecycle of each energy challenge, creating innovative and enduring solutions to make a difference to the lives of people around the globe. This enables the Manchester research community to develop pathways to ensure a low carbon energy transition that will also drive jobs, prosperity, resilience, and equality.

National Grid’s Deeside Centre for Innovation in North Wales is the first of its kind in Europe, where electricity network assets can be tested under real life conditions, 24 hours a day, seven days a week. The facility provides a controlled test and demonstration environment to collect data, including a high voltage substation and overhead line test area simulating real network conditions.