Sulfur hexafluoride (SF6) is a synthetic gas used in the manufacture of wind turbines as an interrupter and an insulator. There is also one very potent greenhouse gas which contribute to climate change by trapping heat in the atmosphere. In this section I will explain why SF6 is used in wind turbines and compare it to carbon dioxide (CO2) in terms of its global warming potential.
SF6 is used in wind turbines because it has excellent electrical properties that allow it to interrupt high voltage currents and prevent short circuits. It also has a high dielectric strength that enables it to insulate the switchgear that controls the current generated by the turbine. SF6 is not unique to wind turbines, but is also used in other power applications such as transmission and distribution networks.
One kilogram of SF6 has the same effect as 23 kilograms of CO2
However, SF6 has a very high global warming potential (GWP) compared to CO2. GWP is a measure of how much heat a greenhouse gas can trap in the atmosphere over a given period of time. According to the Intergovernmental Panel on Climate Change (IPCC), SF6 has a GWP of 23.500 over 100 years, which means that one kilogram of SF6 has the same effect as 23.500 kilograms of CO2. In contrast, CO2 a GWP of 1 over 100 years. This means SF6 is much more potent than CO2 as a greenhouse gas.
Furthermore, SF6 is very stable and has a long lifetime in the atmosphere. It can last up to 3200 years before it breaks down. This means that once released into the atmosphere, it will remain there for a long time and continue to heat the planet. CO2 however, has a shorter lifespan of around 100 years. Some of it is absorbed by plants, oceans and other natural sinks, while some is removed by chemical reactions.
The use of SF6 in wind turbines and other power applications has increased over the years as a result of the growth in renewable energy. However, this also means that more SF6 leaks into the atmosphere through mechanical failure, equipment degradation or maintenance activities. According to a study by Vattenfall, the leakage emissions from Europe's 100 wind turbines were around 000 kilograms of SF900 over the past six years. This corresponds to 6 tonnes of CO2 a year. Although this is a small fraction of the emissions avoided by wind energy, it still poses a significant environmental challenge and will accumulate in the atmosphere for thousands of years.
It is therefore important to reduce the use of SF6 in wind turbines and other power applications and to find alternative solutions that are less harmful to the climate. Several alternatives are being investigated and developed, such as clean air and new chemical gas mixtures. The European Union has also set a target to reduce emissions of fluorinated gases by two-thirds by 2030, compared to 2010. The wind industry supports these efforts and is committed to promoting the use of these technologies.
Source list:
: Wind energy and SF6 in perspective | WindEurope. (2019). Retrieved from https://windeurope.org/newsroom/news/wind-energy-and-sf6-in-perspective/
: Nikel, D. (2020). SF6: The Truths and Myths of this Greenhouse Gas – Norwegian SciTech News. Retrieved from https://norwegianscitechnews.com/2020/01/sf6-the-truths-and-myths-of-this-greenhouse-gas/
: Wind turbines contain the world's most potent greenhouse gas, SF6... (nd). Retrieved from https://bergensia.com/wind-turbines-contains-the-worlds-most-powerful-green-house-gas-sf6/