Wind farms are to be expanded more quickly. But the systems contain a substance that contributes to the greenhouse effect. Although this could be avoided, the EU wants to allow long transition periods.

Sulfur hexafluoride has fascinating properties. Above all: The gas is a perfect insulator. That is why it is mainly used in so-called switchgear – i.e. “nodes” in which the electrical energy is distributed. Gas-insulated switchgear is especially useful where there is little space. This is why such switches are installed in wind turbines, for example.

But the substance also has a fatal property: Sulfur hexafluoride – in short: SF6 – has the strongest greenhouse effect of all known substances. It is around 22,800 times more potent than the same amount of carbon dioxide. And: once it has entered the atmosphere, it takes more than 3000 years for SF6 to decompose again and become ineffective.

This has been known for decades. As early as 1997, the Kyoto Protocol stipulated that emissions of SF6 must be limited. In many earlier areas of application, it no longer plays a role – except in electrical switchgear. There is still no legal regulation for SF6 in this area. Only a voluntary commitment by the industry to only use the substance in closed systems and to recycle or chemically neutralize it at the end of its life. This 1998 commitment also includes that the amounts used and recycled are recorded and reported.

Inaccurate actual emissions data

According to this industry reported data, little SF6 is currently being released into the air. Nevertheless, these amounts in Germany contribute more to the greenhouse effect than the entire domestic German air traffic. A few years ago, when scientists from various universities and authorities around the world compared the actual concentrations in the atmosphere with the reported data, they came to the conclusion that there is almost 50 percent more SF6 in the air in Europe than would be possible according to the reported emission data.

And: Germany is by far the largest emitter in Europe. In plain language: The data reported by the industry must be wrong. A study by the Federal Environment Agency came to the conclusion in 2018 that the monitoring of recycling was insufficient.

No control when recycling

That ARD business magazine Plusminus has therefore asked the most important manufacturers of wind turbines. Nordex and Vestas replied that there is currently no alternative. And: During the operation of wind turbines, only minimal amounts of SF6 escape into the air, and proper disposal at the end of the wind turbine’s service life is ensured.

However, the manufacturers are not responsible for this themselves. Every owner of a wind turbine that needs to be dismantled has to take care of the costly recycling themselves. And when in doubt, it is easier to let the substance escape into the environment. A control does not take place.

Alternatives are often not wanted

Alternatives to SF6 do exist. Siemens Energy developed them for the wind turbines of subsidiary Gamesa a long time ago. There the switches sit in a vacuum tube and are therefore perfectly insulated. Various providers of high-voltage switches, which are used in small substations and have also been insulated with the problematic gas up to now, have already switched to climate-neutral alternatives. Only the manufacturers of wind turbines continue to insist in the tough price competition that the climate killer is still indispensable.

The EU now wanted to restrict and ultimately ban the use of sulfur hexafluoride in a new regulation. This is often a lengthy process in Europe, which the leader of the Greens in the European Parliament, Bas Eickhout, describes as follows: “There were big players in the market who made money from it. They lobbyed successfully and argued that the energy transition should be allowed don’t get in the way and you would need SF6 for that. And: there were also some German companies who put the pressure on.”

The result is sobering: According to the current draft, the use of FS6 in switchgear is only banned from 2030. A transition period of another eight years – although there are already practicable alternatives today.