A $1.2 billion (£1 billion) project to rewire the ageing electricity cables under London will utilize new switchgear and energy-efficiency to meet increasing power demand in the UK's capital city.
This seven-year project is a partnership between the National Grid, London Power Tunnels (LPT) and Hitachi. A new substation in South London is at the center of the project and will be built by infrastructure company Linxon using Hitachi Energy’s SF6-free gas insulated switchgear technology for the first time in the UK. National Grid plans to have no SF6 in any electrical asset by 2050.
Sulfur Hexafluoride (SF6 ) is used in the electricity industry in substations to prevent short circuits and to keep the network safe and reliable, but it is global warming gas and needs to be phased out. National Grid’s ambition is to cut its SF6 emissions by 50% by 2030 and remove all SF6 gas from electrical assets by 2050. This is part of the sum of $1.56 billion (£1.3billion) National Grid is investing each year into the electrical network as part of the movement towards decarbonizing the UK and reaching net zero emissions.
Much of the country's infrastructure is ageing and needs to be replaced. LPT is tasked with rewiring the capital city's cabling, which is often in deep underground tunnels. Replacing these will increase capacity as London and its expanding population will need to access reliable electricity supplies in future.
LPT is building a total of 32.5km of 3m diameter tunnels for high voltage electricity cableways, which will link to the countrywide grid as is required for the system. The first phase of this complex project involves a substantial restructuring of an existing substation in Bengeworth Road, Lambeth, South London, adding a new tunnel access shaft, substation and headhouse within the current site.
Linxon is going to install new equipment in the substation for the transition to SF6 -free operation. In a UK first, Hitachi Energy will deliver EconiQ™ 400-kilovolt (kV) gas-insulated switchgear (GIS) and gas-insulated lines (GIL) containing no SF6, in the upgraded facility. Installation is expected to begin in 2023, subject to approval of the substation by local authority Lambeth Council.
This key power project will deliver a secure energy supply to the capital, and by using more efficient, sustainable technology the outcome will minimize the environmental impact of the operations. By implementing new and transformational engineering the pollution and disturbance will be considerably reduced.
The Hitachi Energy SF6 retrofitting solution was previously piloted at another substation in the UK in 2021, where it proved successful as SF6 was replaced in gas-insulated busbars without changing the equipment, thus avoiding the environmental impact and cost of replacing existing equipment.
Onur Aydemir, Project Director for London Power Tunnels says, “We’re delighted that Bengeworth Road substation, at the heart of London Power Tunnels, will be SF6-free. 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.”
“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,” says Markus Heimbach, Managing Director of the High Voltage Products business at Hitachi Energy. “The EconiQ GIS is based on our breakthrough SF6-free 420 kV circuit-breaker that demonstrates the reliability and scalability of the technology for the lowest carbon footprint.”