The UK has set ambitious targets to become carbon neutral by 2050, however one gas still plagues networks around the world and you might be surprised to learn that it’s 23,500 times more warming than carbon dioxide (CO2).
As networks strive to be carbon natural we still have a reliance on the use of SF6 gas which is used within our medium voltage switchgear for insulation purposes. The remarkable man-made substance has been used in switchgear since the 1960s and is still heavily used to this day. SF6 is a highly potent greenhouse gas. It’s manmade and combines excellent electrical properties with chemical stability and low toxicity. It’s also non-flammable and low in cost and estimates suggest that 80% of its use is in the electricity industry. One kg of SF6 warms the Earth to the same extent as 24 people flying London to New York return.
It’s predominantly used in electrical switchgear (electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment) – creating compact, insulated equipment. SF6 insulated switchgear is compact and also needs less raw material to manufacture.
However this isn’t without a major downside to SF6. It is one of the world’s biggest greenhouse gas contributors, a process causing global warming. The introduction of greater monitoring equipment of SF6 as used to monitor any leaks plus fully hermetically sealed systems have also reduced SF6 losses of the gas into the environment. But while this approach is good for the problems of today, we need to look to technologies of the future in order to properly address the problem of SF6.
In 2019, Siemens launched the UK’s first ‘clean air’ insulated switchgear. It was the first time that clean air has been used instead of SF6 to insulate 145kV circuit breakers in the UK. It uses a gas mix similar to the air we breathe, made up of nitrogen (80%) and oxygen (20%), as a carbon free alternative to SF6.
Siemens has also been developing new insulation technologies to replace SF6 gas for their outdoor and indoor medium voltage switchgear as well. The introduction of our clean air vacuum interrupter technology is a replacement to SF6 gas which provides clean, non-harmful insulation capabilities while maintaining the benefits of compact gas insulated switchgear equipment. The vacuum interrupters are hermetically sealed. The contact gap keeps the switching characteristics of the interrupter’s constant thought the entire lifecycle. By using this technology within the switchgear, we can manufacture reliable and safe equipment whist removing the fluorinated (F) gases.
The clean air vacuum interrupter technology is available on a wide range of our portfolio and is increasing as we continue to develop our product range. Siemens 33kV and below outdoor rated equipment uses the vacuum technology, offering a wide variety of equipment without F gases. Our indoor switchgear, currently rated at 11kV to 24kV, is also available SF6 gas free.
All this proves to me that Siemens is a company committed to deploying its ingenuity for solving the world’s problems and creating environments that care. While there is still a lot of SF6 switchgear out there, we are taking the right steps to not only decarbonise the network but also improve it. Our journey begins today to slowly remove the use of SF6 in the electricity industry and create a greener, smarter grid for the future.