On June 5 Siemens Energy and Mitsubishi Electric signed a Memorandum of Understanding to conduct a feasibility study on the joint development of high voltage switching solutions with zero global warming potential that substitute greenhouse gases with clean air for insulation. Both companies will research methods for scaling up the application of clean air insulation technology to higher voltages. 

They will start with a 245 kV dead-tank circuit breaker that isintended to speed up the availability of climate-neutral high-voltage switching solutions for customers around the globe. Both partners will continue to manufacture, sell, and service switchgear solutions independently. 

Sulphur hexafluoride (SF6), the most potent greenhouse gas, with a potential for global warming roughly 23 500 times greater than CO2, is still the insulating gas of choice, and makes a significant impact on global warming. In the light of the drive toward global decarbonisation, the demand for alternatives is growing, as are regulations to limit the use of , or ban, fluorinated gases.

Siemens Energy and Mitsubishi Electric have both been working on the development of SF6-free gas-insulated switching solutions that replace the greenhouse gas with clean air, a pure mixture of nitrogen and oxygen, in order to contribute to global carbon-neutrality goals. To date, clean air insulation is the only available alternative to greenhouse gases and therefore poses zero health and safety risks. 

  • In April this year Hitachi ABB Power Grids and GE Renewable Energy announced a non-exclusive, cross-licensing agreement related to the use of an alternative gas to sulphur hexafluoride (SF6) used in high voltage equipment, namely a fluoronitrile-based gas mixture that has a significantly reduced impact on the environment compared to SF6. Under this agreement the two companies will share complementary intellectual property related to their respective SF6-free solutions.