It is colourless and five times heavier than air. Illusionists sometimes use it in tricks to demonstrate the levitation of objects. Already a decade ago, the European Union banned the use of this gas in double glazing, tyres, tennis balls or the soles of sports shoes. It is still used in the electricity industry because of its properties. Sulphur hexafluoride has very good dielectric properties, but it has been decided that it must be withdrawn from use. So what will it be replaced with in this industry?
SF6 does not occur naturally in nature; it is an industrial gas. It is a good and readily available insulator, effectively extinguishing the so-called electric arc which is unavoidable during all switching operations in equipment commonly used in the power industry. It is a gas whose use has also enabled the miniaturisation of a number of devices. However, the European Commission is aiming to phase out the use of sulphur hexafluoride from the last area of power generation.
SF6 has made switchgear smaller and safer
The excellent properties of SF6 were discovered in the early 1970s and then new opportunities opened up for designers of high- and medium-voltage switchgear. After all, SF6-insulated switchgear takes up several times less space than conventional switchgear. And they are indifferent to whether the atmosphere is chemically polluted, dusty, containing salts or acid mist. They are also safe from the point of view of explosion and fire, as well as for the personnel operating them, as the live parts are inaccessible.
More harmful to the atmosphere than CO2
However, the most significant disadvantage of SF6 is its very high GWP (global warming potential). This colourless, odourless, non-toxic and five times denser greenhouse gas than air has a global warming potential 23 500 times higher than CO2!
Thus, 1 kilogram of SF6 released into the atmosphere is equivalent to more than 23 tonnes of CO2. It is also an illustrative comparison that just one kilogram of this valuable gas for energy puts the same burden on the environment as 24 passengers flying from London to New York and back.
How to dispose of SF6 so it doesn’t end up in the atmosphere
In Europe, SF6 gas is found in two-thirds of the 15 million high- and medium-voltage switchgear in use. This is a total of 8,600 tonnes, or the equivalent of 196 million tonnes of CO2. Each switchgear consumes up to 2.5 kg of gas. According to Energetyka.plus – the power industry is estimated to be responsible for 80% of the total annual SF6 emissions.
SF6 in itself is not harmful when it does not enter the atmosphere. Emergency leaks of sulphur hexafluoride from equipment are rare. By default, they cannot be higher than 0.1% per year, which over 30 years of trouble-free switchgear operation gives a leakage of less than 3%.
Molecules and toxic substances of this gas, formed as decomposition elements due to arcing, can also be released during the decommissioning of switchgear. It is therefore particularly important to dispose of used SF6, because once released into the atmosphere, it remains in the atmosphere for more than three thousand years! Studies show that its concentration in the atmosphere has doubled over the last twenty years. For the time being, however, there are no EU regulations in place to regulate the decommissioning of installed electrical power equipment and the disposal of SF6.
RES yes, SF6 emissions no
Europe is now in a situation where a shift to renewable energy sources is being promoted and developed. This is leading to an increase in the production of this most potent known greenhouse gas, SF6. This is because energy generation from RES means an increase in the demand for switchgear. To reconcile one with the other without damaging the climate, alternatives to this gas must be sought. Solutions for a smooth transition to SF6-free technologies are already available.
Alternative to SF6
Sulphur hexafluoride is just one of the now infamous family of ‘fluorinated gases’. The European Union has banned the use of many of them. Restrictions on climate-harming SF6 have so far already covered all applications except switchgear, due to its critical function. However, solutions have also been announced for this area by 2026 to help achieve climate neutrality.
Experts note that solutions using SF6 are cheaper, but also require expert handling and therefore special training and certification. However, finding a suitable alternative to SF6 in medium- and high-voltage installations is more challenging.
New green solutions at ZPUE S.A.
ZPUE S.A. was already looking for new, more environmentally friendly solutions for the distribution and transmission of electricity without the use of sulphur hexafluoride. And now European regulations are an additional motivation. With more than 35 years of experience, we have developed a vision of equipment with an alternative to SF6 and a climate-neutral insulating medium. This is how we came up with a product design that already won an award at the ENERGETAB fair in Bielsko-Biała a year ago. This is TPM Air, an innovative compact MV ring switchgear up to 24 kV, without SF6 gas. It is a design based on dry air insulation as well as vacuum technology. It features an innovative solution of a three-position switch, free of SF6, with a close-open-ground function, which means consistent, simple and reliable operation. The use of dry air as the main insulating medium consisting of natural atmospheric air components, guarantees independence from greenhouse gas regulations.