Above: Siemens Energy F-gas-free switchgear production, Berlin

We’re striving for nothing less than the sun: according to a new study by BloombergNEF, a 152 million kilometer supergrid will be needed to enable a global net zero scenario by 2050. That’s twice as long as today’s grid – and if strung together, these lines would reach the sun. Grid expansion is a massive global infrastructure project. With ambitious renewable energy expansion goals in place and ever-increasing electricity demand, power grid operators

are already in the midst of planning and implementing a reliable power grid for the global energy transition. They have to make decisions right now about which operating assets will remain in the grid, in some cases for more than 40 years into the future. The new restrictions on the use of climate-damaging fluorinated gases (F-gases) in switchgear are now a key factor in the grid’s expansion.

The fruit of decades of development work

From a technical point of view, it was a huge improvement when sulphur hexafluoride (SF6) replaced oil as the insulating medium in switchgear in the 1960s. The advantages were clear: with excellent chemical prerequisites for insulating arcs in gas-insulated switchgear, SF6 allowed the equipment to become very compact. The technology was initially met with resistance, which is often the case with innovations that haven’t been used extensively in practice. But eventually SF6, which is one of the F-gases, became the standard solution in switchgear. With climate change and increasing environmental awareness, the major climate impact of SF6 has however come under the scrutiny of industry and governments.

Having 25 200 times the climate impact of CO2, the gas was first regulated in other industries, such as athletic shoe manufacturing, in the European F-gas regulation of 2006. In power transmission, however, there weren’t any alternatives. But manufacturers didn’t stop searching, because sustainability has increasingly become a central evaluation criterion in innovation processes. So SF6 wasn’t a dirty secret of the power transmission industry; rather, it was a driver of decades of research and development work on more climate-friendly, F-gas-free alternatives. European F-gas regulation is key and its recent revision, with stricter restrictions on the use of F-gases, reflect a trend that’s been strengthening technically for a long time – and, from the manufacturers’ point of view, solutions will be in place the beginning of the next decade at the latest.

Future alternatives are F-gas-free

The positions of the European Parliament and the European Council both call for restrictions on F-gases with a high global warming potential (GWP) in new switchgear, staggered according to voltage levels. Even though the GWP limits and exemptions differ, both parties see strong restrictions on the future use of climate-damaging gases being enacted between the end of this decade and the beginning of the next. As an example, Table 1 compares the positions of Parliament and Council on F-gas regulation for high voltage switchgear. The final agreement will be negotiated in a trialogue between the European Council, Parliament, and Commission, with the outcome expected to emerge in Brussels later this year.


But what SF6 alternatives can distribution and transmission system operators use today? The alternatives to SF6 currently on the market can essentially be divided into two groups:

  1. Switchgear that continues to rely on the “forever chemicals” PFAS (per- and polyfluorinated alkyl compounds) such as fluoronitrile. Fluoronitrile mixtures have a much lower GWP than SF6, but it’s still a climate-impacting F-gas, so the GWP is still several hundred. The current positions of the European Parliament and the European Council would in principle ban the new installation of fluoronitrile-based equipment in Europe in a few years when more F-gas-free alternatives are available.
  2. Switchgear that use gases of natural origin. These are gas mixtures of nitrogen, oxygen, or CO2 for insulation and have a GWP lower than 1. Today, the majority of switchgear manufacturers are already using gases of natural origin, and Siemens Energy has teamed up with five of the leading manufacturers of medium and high voltage switchgear and jointly founded the “Switching Gears for Net Zero Alliance.” The six members (Mitsubishi Electric, Toshiba, Siemens, Schneider Electric, Nuventura, and Siemens Energy) all offer equipment that uses gases of natural origin, and they’ve demonstrated for many years that power transmission without using F-gases is technically feasible and operates reliably.

Siemens Energy decided early on to go for the “zero solution” with our Clean Air solution as an alternative to SF6: zero compromise; zero impact on the environment; and a GWP of zero. Clean Air is synthetic air consisting of 80% nitrogen and 20% oxygen. Synthetic air is also found in other applications, eg, artificial respiration, for example. If it escapes from switchgear, it’s harmless to animals, humans, and the environment. Siemens Energy has already sold more than 3000 units from its F-gas-free Blue Portfolio. Experience in operation has been positive, and the technology is proving reliable.

Siemens Gamesa is already using SF6-free high voltage switchgear exclusively in its offshore wind turbines and has also announced its intention to phase out SF6 gas in all new medium-voltage switchgear for use in onshore wind turbines as soon as possible, no later than 2030 worldwide, and to replace it with alternatives with a global warming potential of less than ten.

Taking advantage of transition periods, creating planning certainty

In November 2021, Siemens Energy announced plans to invest more than €60 million in a new production facility in Berlin for more environmentally friendly switchgear. Vacuum interrupters will be manufactured there in the future on a 6200 m2 site. Vacuum interrupters are at the technological heart of the company’s F-gas-free Blue Portfolio.

Even though the switch to F-gas-free, climate-friendly power transmission with Clean Air was made at Siemens Energy years ago, the new European regulation still represents an important confirmation for all switchgear manufacturers, and they can now make long-term investments in their production capacities. That’s because the ambitious expansion targets for renewables and the simultaneous increase in electricity demand are necessitating an unprecedented expansion of power grids. The new European regulation is therefore an important piece of the puzzle in the quest by an entire industry for more planning security so it can sustainably meet these requirements over the long term. At the same time, policymakers around the world need to advocate for reforms to the regulatory framework and permitting processes, and also support supply chains in order to achieve the level of investment needed for grid expansion.

F-gas-free power transmission technology is reliable, and manufacturers have a clear roadmap for closing gaps in their product portfolios, taking into account the current positions of political institutions and what we see as a realistic transition phase. For manufacturers and grid operators, it’s now a matter of using the transitional phases to progress together along the path toward F-gas-free power transmission.