Is it time to confront SF6 gas?
"SF6 gas is simply the most potent greenhouse gas we know of," explains Kristian Førby Pedersen, Product Manager for Powertech at Hans Følsgaard A/S. "To put it into perspective, one kilogram of SF6 gas is equivalent to no less than 23,500 kilograms of CO2. It was designated as one of the gases to be phased out in the Kyoto Protocol, but it has been challenging to do so because it also has some unique properties."
The product manager refers, among other things, to the widespread use of SF6 gas in medium-voltage systems, where its insulating properties allow for compact and cost-effective constructions. These are tough odds to overcome, but now several factors indicate that changes may be on the horizon.
Starting on July 1st this year, the tax per kilogram of SF6 in Denmark will be increased from 600 to nearly 4,300 Danish kroner, and in 2024, the tax will be further adjusted to 4,700 kroner per kilogram. This will dramatically reduce the price difference compared to SF6-free systems, and there are many good reasons to welcome this development.
"Most politicians want to promote further electrification in Denmark. Our heating, our fuel for vehicles, everything should be powered by electricity, which we need to produce more of ourselves through green technologies like solar and wind energy. This requires the use of more switchgear," says Kristian Førby.
A challenge for sustainable energy
Green and sustainable solutions are gaining strong momentum in recent years, which is a positive and ongoing trend. The green transition is driven by solar energy, wind energy, and heat pumps. However, when these systems need to be connected to the grid, it often happens through equipment containing SF6 gas due to the gas's excellent electrical properties. When the equipment is enclosed in a tank filled with SF6 gas, sparks are immediately suppressed.
SF6-based systems have been inexpensive to purchase, but apart from the potential environmental and climate hazards, they have also had some hidden costs that were not always accounted for. This includes tank refilling, inspections, personnel certification, and safe disposal. Alongside the upcoming significant tax increases, this could fundamentally change the equation when it comes to sustainable energy solutions.
Alternatives are catching up
There are currently three alternatives to using the super-potent greenhouse gas SF6 as an insulation material in medium-voltage systems. One option is encapsulating the equipment using solid materials such as resin. The second is working with air insulation, and the third is using a less potent gas.
Insulation with air or solid materials means that it is possible to completely avoid the use of environmentally hazardous SF6 gas and avoid hidden expenses related to inspection, certification, refilling, and decommissioning.
"SCELL from Tavrida is a good example that today you can build compact systems that are entirely SF6-free," says Kristian Førby Pedersen. "There are no pressurized tanks and no dangerous greenhouse gas that can escape into the atmosphere, where it would remain active for more than a thousand years. Tavrida uses a sandwich insulation of air and solid material to protect the components, and as mentioned, they can do it in very compact dimensions."
According to the product manager and his colleagues at Hans Følsgaard, the alternatives to encapsulating with SF6 gas are stronger than ever. Modern solutions and components for medium voltage can now not only match traditional systems in terms of price and safety but can also be manufactured with the recycling of complete systems in mind. This should be of particular interest to green energy technologies.
Phasing out seems inevitable
The question is how long the expansion of green energy distribution in Denmark can continue with the help of the most potent greenhouse gas we know. Both nationally and internationally, there is a focus on this issue, and it seems only a matter of time before SF6 gas is either banned or subject to such significant taxes that it no longer makes sense to use it.
"In my opinion, phasing out SF6 should be inevitable, and I believe the time is now ripe to confront the use of SF6 gas in the medium-voltage sector. At Hans Følsgaard, we are ready to drive the development by offering energy companies and distributors a constructive collaboration to implement more forward-looking technologies. I think it's only going one way, and therefore, it makes sense for stakeholders to start adapting to more climate-friendly solutions now," concludes Kristian Førby Pedersen, Product Manager for Powertech at Hans Følsgaard A/S.
