Many large circuit breakers are filled with sulphur hexafluoride (SF₆) – a greenhouse gas that is 24 300 times more powerful than CO₂. But an ingenious Norwegian solution could offer us a climate-friendly alternative.
By Hege Tunstad - Published 11.03.2026
The EU has already required mandatory reporting and phasing out of the greenhouse gas SF₆. The reason is that even small leaks cause large emissions.
SF₆ gas is already heavily regulated and managed, but so far circuit breakers have been excepted from the ban. However, new breakers in medium-voltage systems (up to and including 24 kV) must be SF₆-free starting in January this year, while the deadline for the highest voltage is 2032.
Norway is expected to introduce similar regulations soon, and the industry wants to be at the forefront of the changes.
Adapting breaker look and function for SF₆ alternative
The eleven largest power grids in Norway have already signed a joint agreement to stop buying new grid components that contain SF₆ gas.
But intentions alone are not enough. So what will the breakers look like, and how will they function without the use of SF₆? And how will we get there?
Researchers are working on this now. SINTEF, NTNU and the ABB group are collaborating to develop breakers that can replace some of these “climate bombs” in the power grid.
“Replacing SF₆ in circuit breakers is technically demanding and will entail a number of compromises,” says Nina Sasaki Støa-Aanensen, a senior research scientist at SINTEF Energy.
More on that to follow.
Why do we have breakers in the grid?
Have you ever finished up your vacuuming, and just pulled the plug out of the wall instead of using the vacuum cleaner’s on/off switch?
Did you perchance notice a tiny flash of light inside the socket? What you saw was an electric arc flash.
Circuit breakers are absolutely crucial for controlling the flow of energy in the power grid. The small arc in your home electrical system can just die out on its own, because the voltage is so low.
But every time the power has to be disconnected in the much higher-voltage power grid, arcing occurs that can reach temperatures as high as 10 000 degrees Celsius.
Disconnecting the power is sometimes necessary in situations of extreme weather, falling trees and power outages – or in the worst case, sabotage.
Breakers are almost like small fire stations in our electrical grid – they extinguish the flames and prevent the fire from flaring up again.
So breakers need to be able to extinguish the arcs safely.
Essential for safety
These breakers have to simultaneously isolate the high voltages to prevent current from finding unwanted paths, says Støa-Aanensen.
“Breakers are almost like small fire stations in our electrical grid – they extinguish the flames and prevent the fire from flaring up again,” says the researcher.
The circuit breakers must also be able to withstand extreme climate conditions, from bitter cold to extreme heat, humidity and salty air, she adds.
“And they have to be reliable for several decades, like 40–50 years. SF₆ has been a “magic gas” in meeting all these needs. It has been challenging to find alternatives that are both environmentally friendly and technically on par with SF₆,” Støa-Aanensen says.
This research requires expertise in electrical, mechanical and thermal design, as well as many calculations and physical testing.
Can air solve the climate problem?
It is absolutely crucial for researchers and industry to establish productive and close cooperation in order to find suitable solutions.
Research efforts have included testing the use of so-called technical (or dry) air, as a switching medium that could replace SF6 as the gas within electrical switchgear .
SF₆ has served as a “magic gas” for all these needs.
“In this particular project, we’re working on a solution using pressurized air. We use twice as high a pressure as exists in the atmosphere, for both circuit breaking and insulation,” says Støa-Aanensen.
Air has a global warming potential of 0, and it satisfies EU requirements plus solves the switchgear’s greenhouse gas problem.
“Using pressurized air instead of SF₆ as an insulation medium, we have to increase the filling pressure in switchgear to achieve the same performance. At the same time, we need to improve the internal design, ranging from switchgear – or “fire extinguisher” – to all the transitions between the different materials,” she says.
“Over time, we’ve found that the system’s arc-quenching capability works well,” says the researcher.
So perhaps that solves the problem, right? Well, it’s not quite that simple.
Forever challenges: PFAS
Even though the researchers have found solutions that allow SF₆ to be phased out, more challenges are still queued up and waiting to be addressed. And that applies not only to the gas inside the switches, but to the switch housing itself.
“All breakers contain PFAS – so-called forever chemicals,” says Støa-Aanensen.
PFAS come in many variations, but they are often characterized by several important technical properties. They can withstand high temperatures, they have low surface tension and high electrical insulation,” she says.
But just like SF₆, PFAS also have their difficult sides: PFAS do not easily degrade in nature, and they accumulate in the environment and body.
First prototypes have been tested, with promising results
So even though we’ve solved a major problem by going SF₆-free,’ says Støa-Aanensen, “we may also have to replace other materials that are used in today’s switches.
PFAS is not yet banned in the EU, but the environmental agencies of five countries, including the Norwegian Environment Agency, have issued a broad proposal for restricting PFAS.
“The proposal will be come up for political consideration in the EU in the coming years,” says Støa-Aanensen.
We have to constantly be at the forefront of developments, says the researcher.
“In the collaborative project with ABB and NTNU, we are therefore trying to find solutions that are not only SF₆-free, but also free of PFAS in the switch chamber itself. The first prototypes have been tested in the lab, with promising results,” she says.
Research and industry hand in hand
FreeSwitch is the name of the project that Støa-Aanensen is referring to.
This project is based on more than 20 years of collaboration on research and industrial development, and is supported by the Research Council of Norway’s scheme for innovation projects in business (IPN).
“This is a typical example of how research and industry can drive green transition together,” says Martin Kristoffersen, the project leader at ABB’s technology centre in Skien.
ABB has had a factory in Skien for over 100 years, has almost 1000 employees and is Skien’s largest workplace. ABB has several departments distributed across nine locations in Norway.
They have their headquarters in Fornebu municipality and employ a total of 2200 people nationally.
Job-creating possibilities
The fact that ABB still has a factory in Skien is also linked to its close collaboration with SINTEF and NTNU, says Kristoffersen.
“When research environments are connected directly to us in industry, we gain both technological solutions and competitiveness. This arrangement ensures high quality and reliability when we develop products for the future distribution of electrical energy – and that creates jobs,” he says.
In this way, the research collaboration is not only a climate measure, but simultaneously strengthens Norwegian industry.