Climate-neutral technology to transmit clean energy along HVDC link

Siemens Energy’s 8VN1 clean air technology to be installed in new substation on Shetland

Siemens BAM, has been appointed by Scottish and Southern Electricity Networks (SSEN) to construct a new HV AC substation as part of wider works to connect Shetland and the north of Scotland. To achieve project requirements of constructing an efficient, secure, and reliable link and associated infrastructure is relatively straightforward when you have the proven technical expertise. But when there is also the prerequisite for a solution that contributes to net zero targets, this is where innovation and advanced technology meets expert engineering to deliver a future-proofed system. 

Shetland is set to be connected for the very first time to the UK electricity transmission network. The Shetland  link will provide security of supply to the island  and will also enable the development of new renewable electricity assets and the connection of existing ones across the island to transmit energy to the mainland for distribution throughout the UK.


Siemens Energy’s customer, SSEN, secured final approval for the link, which is an integral component of its low carbon investment programme, from the UK’s energy regulator – Ofgem – in July 2020. The link consists of an AC substation at Kergord on Shetland, a HVDC converter station – also at Kergord – and 257 kilometres of subsea cable to transport the power to a HVDC switching station at Noss Head in Caithness in the north of Scotland. Selected for its proven experience with SSEN  on previous projects, and as a leading specialist in the construction of substations, the successful joint venture – Siemens BAM – will be constructing the 145kV gas insulated switchgear (GIS) substation at Kergord using Siemens Energy’s world leading, environmentally friendly Blue GIS technology.


This innovative technology supports SSEN Transmission’s programme to significantly reduce its greenhouse gas emissions through its climate-neutral, reliable power transmission capability. Mark Tiernan, Siemens Director High Voltage Substations, said: “We are delighted to be undertaking the 145kV GIS Substation works and are looking forward to starting construction in 2021. We have worked closely with SSEN and we are pleased to have a GIS substation design that meets our societal obligation to reduce our carbon footprint by including Siemens Energy’s climate neutral GIS technology.” 

Planet-saving technology 

The drive to meet net-zero targets has stimulated the design of environmentally friendly technology across the electrical industry in recent years. Siemens Energy’s own contribution was the development of an innovative solution whose clever design incorporates alternative technologies to enable the F-gas-free, secure transmission of electrical power. F-gases are frequently used for their electrical insulation properties; however, due to their potency, they have an effect on global warming that is a massive 23,400 times more than carbon dioxide and can remain active in the environment for over 3000 years.


Counteracting the F-gas effect is Siemens Energy’s 8VN1 blue GIS up to 145kV. Operational in projects throughout the world since 2017, it is proven to deliver significant environmental benefits with its climate-neutral ‘clean air’ insulation that has a Global Warning Potential (GWP) of zero.


Chris Hull, Engineering Manager (GIS), Siemens Energy, said: “SSEN Transmission’s own 11Bay 145kV Blue Substation at Kergord will deliver benefits and savings across the board thanks to the incorporation of 8VN1 technology. Our vacuum interrupter unit withstands frequent switching operations throughout its lifetime and - as it’s hermetically sealed-for-life technology – is maintenance free. The technology also delivers high reliability, high performance and an improved operation temperature range.” 

What could be more environmentally friendly than clean air?

Siemens Energy’s clean air insulated technology is not only good for the environment but the absence of F-gas will also benefit SSEN  through a reduction in training requirements, in transportation and installation, and in reporting and recycling costs that are associated with F-gas use. The solution meets the environmental objectives of the Shetland HVDC link and will also produce future savings due largely to the elimination of the risk of future CO2 tax and compensation costs.


For a project that, at every stage, has a focus on bringing clean electricity to consumers and sharing renewable sources, it would have been counterintuitive to use anything but the latest in environmentally friendly and future-proofed technology.


Richie Atkinson, Lead Project Manager, Siemens Energy, said: “When the substation works start at Kergord in July 2021, Siemens BAM can be proud that we’re delivering infrastructure and technology that will support our customer’s commitment to the environment. Not only will this project enable the transmission of clean energy, but we know it will also provide economic support to local communities in Shetland and north Scotland. That’s a win-win for us.”