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SSEN Transmission’s sites lead the way with use of new environmentally-friendly gas insulated switchgear

SSEN Transmission’s sites lead the way with use of new environmentally-friendly gas insulated switchgear

As part of its forthcoming projects at Fort Augustus, Inverness-shire, and New Deer in Aberdeenshire which both start in April, SSEN Transmission has signed a contract with a GE/Amey consortium which will see the installation of GE’s gas-insulated switchgear & busbar utilising  g3 gas in place of SF6 (sulphur hexafluoride).

Due to its extremely good insulating properties, SF6 gas is widely used in substations across the globe, with the transmission industry accounting for around 80% of the world’s usage.

However, it is also a greenhouse gas with a Global Warming Potential [GWP] 22,800 times that of CO2 which stays in the atmosphere for around 3,200 years. Strict regulations control the use of SF6 gas, which are encouraging the utility industry to reduce its useage to help meet climate change objectives. GE’s development of a greener alternative gas can reduce the environmental impact of such systems by as much as 99%.

  • With  g3-insulated busbars (GIB) measuring over 1km, the New Deer site will see the world’s largest volume of the gas installed at one location.
  • The Fort Augustus substation expansion will be the first transmission site in the country to have a fully g3-insulated substation and also a significant length of  g3-insulated GIB.

Commenting on this major breakthrough for the industry, Dave Allan, SSEN’s Technical Engineering Manager, said:

“As a responsible developer, we are determined to do everything we can to reduce the environmental impact of our activities. While our most material contribution to action against climate change is our role in enabling the transition to a low carbon economy, we are also determined to tackling our own emissions.

 “By using this innovative new gas at Fort Augustus and New Deer, not only are we reducing the environmental impact on our own network, we are hoping that this will also demonstrate to the wider transmission industry that there is a viable alternative to SF6 out there, and one which they may consider using in similar scenarios in the future.”

Dirk Uhde, Excecutive, GIS Product Manager, GE, said

 “We are delighted to support SSEN Transmission in making significant reductions in the reliance on SF6 gas in high voltage switchgear.  Fort Augustus is the first substation using both 145 kV g3 switchgear and 420 kV g3 gas-insulated busbar.  New Deer is the longest 420 kV g3 GIB ordered to date.  Using g3 instead of SF6 in those two substations will avoid the installation of approx. 200,000 tons of CO2 equivalent. That’s equal to removing 43,500 passenger vehicles from the road for one year.  Our latest switchgear not only utilises g3 instead of SF6 but also features the most compact dimensions in the industry.  Consequently, the product’s Life Cycle Assessment (LCA) shows the lowest environmental footprint along the whole life cycle.”

In June 2018, SSEN Transmission demonstrated its commitment to supporting local and global efforts to tackle the threat of climate change when it confirmed its ambitions to set a science-based target for reducing its greenhouse gas emissions.  This is designed to ensure SSEN Transmission achieves a level of decarbonisation in line with climate science, consistent with the landmark Paris agreement.

Today’s announcement further supports progress to achieving this vision, putting SSEN at the forefront of the GB transmission industry as the first company to use g3 in its transmission substation switchgear.

SSEN‘s environmental commitments were also highlighted in November last year when the energy regulator, Ofgem, awarded it ‘leadership’ status for its 2017/18 Environmental Discretionary Reward (EDR).  EDR is an incentive for transmission owners to demonstrate a strategic environmental focus in helping facilitate growth in low carbon energy.


  • SSEN Transmission, operating as Scottish Hydro Electric (SHE) Transmission plc under licence, owns, operates and develops the high voltage electricity transmission system in the north of Scotland and remote islands. 
  • SSEN’s strategic priority for the RIIO-T1 price control period has been to enable the transition to a low carbon economy through building the transmission infrastructure necessary to connect and transport renewable energy.
  • Since the start of RIIO-T1 in April 2013, SSEN Transmission has invested over £2.5bn in the north of Scotland transmission system, supporting the growth of renewable energy across the region which has grown from 3.3GW to over 6GW as at 30 September 2018. 
  • GE has developed Green Gas for Grid, (aka g3 and pronounced g-cubed) to have similar technical performance as SF6 but with a greatly reduced environmental impact. Using g3 gas in HV switchgear results in over 99% reduction in global warming impact compared with SF6.  g3 products feature the same dimensional footprint as the state-of-the-art SF6 ones, and they operate with no restriction under the same temperature range (down to -30°C).
  • For more information on g3 and its environmental benefits, please visit GE’s dedicated webpage: https://www.gegridsolutions.com/productexplorers/greengas/?adredir=4321&utm_source=gswebsite&utm_medium=product-page&utm_campaign=g3-explorer#/
  • The Fort Augustus project is scheduled to begin its main construction phase in April 2019 and is expected to be completed in October 2021. Upon completion, the project will provide additional capacity on the transmission network and provide firm connections for the Bhlaraidh and Beinneun wind farms.
  • In April this year, SSEN Transmission will commence construction of its substation at New Deer, which will facilitate the connection of Moray Offshore Wind Farm.