National Grid is set to integrate green technology to reduce the use of sulphur hexafluoride (SF6) from the £1 billion London Power Tunnels (LPT) project.
The first phase of the LPT project was completed in 2018 and saw London rewired from Hackney to Willesden and from Kensal Green to Wimbledon to meet increasing electricity demand. The next stage will see new cables replace three circuits of cables that run under the surface of roads between Wimbledon in the southwest to Crayford in the southeast.
To support the project, National Grid is creating a tunnel access shaft, substation and headhouse with UK Power Network’s existing substation site boundary at Bengeworth Road, Lambeth.
Construction engineering company Linxon is building the Bengeworth Road substation for National Grid. Hitachi Energy will deliver EconiQ 400kV gas-insulated switchgear and gas-insulated lines containing no SF6. This will reduce the emissions of the substation and LPT project.
Installation is expected to begin in 2023 subject to prior approval of the substation by Lambeth Council.
“We’re delighted that Bengeworth Road substation, at the heart of London Power Tunnels, will be SF6-free,” said Onur Aydemir, project director for London Power Tunnels.
“This key power project will deliver a secure energy supply to the capital, and by using sustainable technology we are minimising the environmental impact of our operations and using transformational engineering to support the transition to net zero.”
SF6 has a global warming potential that is 25,200 times greater than CO2 but is a highly efficient electrical insulator. It can be utilised within various applications such as medium and high voltage switchgear and circuit breakers.
It has been instrumental in the creation of the UK power network however National Grid has made a commitment to reduce SF6 emissions by 50% by 2030 ahead of its full removal by 2050.
National Grid has been exploring the creation of a retrofill solution to remove SF6 across its network of high-voltage equipment in partnership with the University of Manchester. To achieve this, the two organisations are collaborating on the creation of a retrofill solution to replace SF6 with an environmentally friendlier alternative without having to replace or otherwise modify the existing equipment.
The University of Manchester and National Grid are aiming to create a physical demonstration with an inbuilt condition-based monitoring system that will focus on the applicability of SF6 retrofill techniques.
In a separate pilot project last year, National Grid and Hitachi Energy developed and deployed a solution at Richborough substation in Kent to replace SF6 with a greener alternative.
“Following the successful collaboration with National Grid on the world’s first replacement of SF6 in existing high-voltage equipment and award-winning project in Richborough, UK, we are proud to be supporting National Grid again in its transition to SF6-free solutions,” said Markus Heimbach, managing director of the High Voltage Products business at Hitachi Energy.
“The EconiQ GIS is based on our breakthrough SF6-free 420kV circuit-breaker that demonstrates the reliability and scalability of the technology for the lowest carbon footprint.”
