They have the same functionality as conventional medium voltage (MV) switchgear and a similar footprint. However, they prove to be more cost-efficient over their entire lifecycle. Most importantly, they have a significantly lower environmental impact. How? They are completely free of sulfur hexafluoride (SF6), a gas with a very high global warming potential. Siemens’ SF6-free MV switchgear has now also arrived on the Italian market, with the company presenting its new portfolio of medium voltage switchgear, blue GIS, on October 2.
Towards a More Climate-Friendly Energy Distribution
Thanks to its physical and chemical properties, sulfur hexafluoride (SF6) is an inert gas with excellent insulating qualities. Transparent, odorless, non-toxic, and non-flammable, SF6 has high thermal stability and significant electrical resistance, making it particularly suitable for various industrial applications, especially as a dielectric and thermal insulator. Today, most of the SF6 produced is used in circuit breakers and disconnectors in power transmission and distribution lines.
However, SF6 is also one of the most potent greenhouse gases. According to the latest report from the UN Intergovernmental Panel on Climate Change (IPCC), sulfur hexafluoride is 24,300 times more powerful than carbon dioxide (CO2), and 18,200 times more powerful in the first 20 years it remains in the atmosphere. In other words, releasing 1 kg of SF6 into the atmosphere is equivalent to emitting 24.3 tons of CO2. Moreover, this gas can persist in the atmosphere for up to 3,200 years. Like other fluorinated gases (F-gases), SF6 has been used in industrial applications for about 35 years as a replacement for substances phased out under the 1987 Montreal Protocol due to their ozone-depleting effects.
The Ban on F-Gases in the EU
For these reasons, as part of the Green Deal, the European Union has revised its regulations on fluorinated gases in recent years. After two years of work, on February 7, 2024, Brussels approved Regulation 2024/573, which formally came into effect on March 11 of this year.
This new EU regulation replaces the previous one, enacted 10 years earlier, and establishes a system aimed at gradually reducing the availability of F-gases on the market. Specifically, the regulation sets out provisions for the containment, use, recovery, recycling, regeneration, and destruction of fluorinated gases. It also addresses both the gases themselves and the equipment that uses them, including switchgear.
For this type of equipment, the new regulation mandates the gradual phase-out of medium voltage switchgear that uses SF6. The phase-out begins in January 2026 and proceeds in incremental stages, leading to a complete ban on the sale of new SF6-based medium voltage switchgear by 2031.
SF6-Free Medium Voltage Switchgear: Siemens’ Proposal
The phase-out mandated by Brussels will proceed swiftly, as there are no real technological barriers: SF6-free alternatives are already widely available. Many companies, including Siemens, have not waited for the new EU regulations to integrate SF6-free switchgear into their product offerings.
“Today at Siemens, we are announcing that we are already capable of providing gas-insulated switchgear (GIS) up to 24 kV without using fluorinated gases. This allows our customers to avoid compromising on safety, availability, lifecycle costs, or size,” explains Marco Rastelli, Head of Electrification and Automation at Siemens Smart Infrastructure.
The launch in Italy follows the successful national regulatory tests for the blue GIS medium voltage switchgear, which have already been installed in several European countries. But what are the technical details, and how is SF6 replaced?
Clean Air: The Clean Alternative to SF6
Instead of sulfur hexafluoride, Siemens’ new medium voltage switchgear uses vacuum switching technology and an insulating gas of natural origin called Clean Air. This gas consists of components naturally present in the atmosphere. It is free of F-gases, non-toxic, non-flammable, stable, and harmless, making it suitable for all operating temperatures. It guarantees the same functionality as conventional switchgear and occupies the same space, but offers greater efficiency over its lifecycle and a significantly reduced environmental impact.
Milan Leads the Way in Sustainable Energy Distribution
Siemens’ SF6-free medium voltage switchgear is already operational in Italy, thanks to a pilot project involving Siemens and Unareti, a subsidiary of the A2A Group that manages around 15,000 km of energy and gas distribution networks. The trial began in Milan with the installation of the first medium voltage switchgear insulated without SF6. The aim is to deliver electricity to a section of the city using Siemens’ Clean Air technology. “We started with an initial installation in Milan, and we are pleased with the positive start of this pilot project, which will allow us to have sustainable equipment for the development of electrical infrastructure that will require significant investments in the coming years,” commented Francesco Gerli, CEO of Unareti.