EU LIFE Blue GIS 420 kV

Almost all high-voltage electrical switchgear in the last fifty years has used SF6-gas for insulation. SF6 is extremely climate-hostile, with a global warming potential (GWP) of  

24,300. Clean air insulation and vacuum switching technology, both of which have a GWP of zero, are increasingly used in 72.5 kV and 145 kV switchgear as an alternative to SF6. Until now, however, these have not been commercially available in 420 kV equipment. Both technologies stand for zero compromise in respect of the environment, health and safety. 

The aim of the LIFE Blue project is to demonstrate for the first time the economic viability of a climate-friendly 420 kV gas-insulated switchgear (GIS) completely free of fluorinated greenhouse gases (F-gases) and intentionally free of PFAS  – which is not the case with other alternatives to SF6. In addition, the project will deliver the world's first 420 kV low power instrument transformer (LPIT) with cast resin embedded sensors and clean air insulation, replacing conventional current and voltage transformers. The LPIT will offer new digital possibilities in current and voltage metering and additional functions such as power quality measurement and will help to significantly reduce the size and copper cabling of SF6-free GIS solutions. 

Backed by EU funding and in partnership with Elia, operator of the electricity transmission network in Belgium, this Blue GIS will be installed at the transmission system operator (TSO) Elia site near Brussels replacing an existing indoor GIS with SF6. The clean air set to be used instead consists of nitrogen and oxygen and has a GWP of zero. Siemens Energy and ELIA entered this partnership in October 2024, which is scheduled to continue until September 2028. Over the course of those four years, both parties will conduct: 

1 Step 

Development and testing of the LPIT solution for Blue 420 kV GIS 

2 Step 

Type testing of the CB (including LPIT) 

3 Step 

Pilot installation of 1 GIS bay in the ELIA substation (including engineering, manufacturing, instrumentation and control) 

4 Step 

Operation at ELIA substation for 1 year (+5 years) including monitoring, evaluation and technical assessment