The Carbon Footprint of SF₆ vs SF₆-Free Switchgear

Medium-voltage (MV) switchgear is a long-lived asset — often installed for 30 to 40 years. While it is not an energy-consuming device in the traditional sense, its choice of insulation medium can have a significant climate impact over its lifetime.

For decades, sulphur hexafluoride (SF₆) has been widely used in gas-insulated switchgear (GIS) due to its excellent dielectric properties. However, SF₆ is also the world’s strongest greenhouse gas. As utilities and industries align with net-zero targets, understanding the carbon footprint of SF₆-based vs SF₆-free switchgear has become critical.

This article explains where emissions arise, how they are calculated, and why SF₆-free GIS fundamentally changes the climate equation.

1. Why Switchgear Has a Carbon Footprint at All

Although switchgear does not burn fuel, its carbon footprint arises from three main sources:

1. Embedded emissions
   
    
   • Materials (steel, copper, aluminium, epoxy)
    
   • Manufacturing and transport
2. Operational emissions
   
    
   • Greenhouse gas leakage over the asset lifetime
    
   • Maintenance activities
3. End-of-life emissions
   
    
   • Gas recovery, handling, and disposal
    
   • Risk of residual gas release

For SF₆-insulated switchgear, operational and end-of-life emissions dominate the footprint.

‍

2. SF₆: A Small Quantity with a Massive Climate Impact

SF₆ is used because it is:

• Electrically insulating
• Chemically stable
• Non-flammable

Unfortunately, these same properties make it extremely persistent in the atmosphere.

Key facts about SF₆

• Global     Warming Potential (GWP): ~23,500
      → 1 kg of SF₆ = 23.5 tonnes of CO₂ (over 100 years)
• Atmospheric lifetime: >3,000 years
• No natural sinks

Even very small leaks therefore have outsized climate consequences.

‍

3. Where SF₆ Emissions Occur in Real Life

Despite strict handling procedures, emissions occur at multiple stages:

3.1 Manufacturing & commissioning

• Gas filling
• Quality testing
• On-site commissioning

3.2 Normal operation

• Micro-leakage through seals over decades
• Typical guaranteed leakage rates are low, but never zero

3.3 Maintenance & servicing

• Gas handling during repairs
• Human error during filling or recovery

3.4 End-of-life

• Incomplete gas recovery
• Residual gas trapped in compartments
• Disposal and recycling risks

Because GIS assets remain in service for decades, even small annual leakage rates accumulate into material emissions.

‍

4. End-of-Life Reality: Why SF₆ Is Effectively a “Delayed Emission”

A critical but often underestimated aspect of SF₆ is end-of-life disposal.

According to the California Air Resources Board (CARB), the recovery, destruction, and permanent containment of SF₆ is technically complex, energy-intensive, and expensive. Destruction requires specialized high-temperature plasma or thermal oxidation processes, certified facilities, and tightly controlled logistics — all of which limit scalability and increase cost.

While regulations require SF₆ to be recovered at decommissioning, there is no simple or universally deployed pathway to permanently eliminate the gas without risk of release. In practice, recovered SF₆ is often:

• Stored for long periods
• Re-used in other equipment
• Transferred across borders

rather than definitively destroyed.

As a result, SF₆ should not be seen as a permanently contained substance, but as a “delayed emission”:
SF₆ that is produced today will, with high likelihood, eventually be emitted into the atmosphere over time.

Given SF₆’s extremely long atmospheric lifetime and very high GWP, this makes every kilogram of SF₆ produced a long-term climate liability, regardless of how carefully it is handled during its service life.

‍

5. SF₆-Free Switchgear: What Changes Fundamentally

SF₆-free GIS replaces fluorinated gases with dry air or clean air (typically nitrogen/oxygen mixtures) combined with vacuum interruption.

Key differences

• GWP = 0
• No fluorinated greenhouse gases
• No long-term atmospheric persistence
• No climate impact from leakage

Even if all insulation gas were released, the CO₂-equivalent impact is effectively zero.

‍

6. Lifecycle Carbon Comparison: SF₆ vs SF₆-Free GIS

Manufacturing

• Both technologies use similar metals and insulation materials
• Embedded emissions are broadly comparable

Operation

• SF₆ GIS:
  
   
  • Continuous climate liability due to leakage risk
• SF₆-free GIS:
  
   
  • No operational greenhouse gas emissions

Maintenance

• SF₆ GIS:
  
   
  • Gas handling, reporting, certified personnel
• SF₆-free GIS:
  
   
  • No gas reporting, no special equipment

End-of-life

• SF₆ GIS:
  
   
  • Mandatory gas recovery and disposal
   
  • Residual emission risk remains
• SF₆-free GIS:
  
   
  • No greenhouse gas recovery required

Result:
Over its lifetime, SF₆-free GIS has a dramatically lower carbon footprint, even if initial material emissions are similar.

‍

7. Regulatory and Reporting Implications

The climate impact of SF₆ is no longer just an environmental issue — it is a regulatory and financial one.

Utilities and industrial operators increasingly face:

• Mandatory SF₆ inventories
• Leakage reporting
• Carbon accounting under Scope 1 emissions
• Rising carbon prices
• Public ESG disclosure requirements

By contrast, SF₆-free GIS:

• Eliminates SF₆ from Scope 1 emissions
• Simplifies compliance
• Reduces long-term regulatory risk

‍

8. Beyond Carbon: Secondary Environmental Benefits

SF₆-free switchgear also avoids:

• Toxic decomposition by-products during arcs (e.g. HF)
• Special PPE and neutralization procedures
• Environmental risks during accidents

This improves worker safety and reduces indirect environmental impacts.

‍

9. Why Carbon Footprint Matters for Grid Planning

As electricity grids expand to integrate renewables, datacentres, EV charging, and electrified industry, MV switchgear volumes are increasing rapidly.

Choosing SF₆-free technology:

• Prevents long-term locked-in emissions
• Aligns grid expansion with climate targets
• Avoids stranded assets as regulations tighten

In this context, insulation choice is no longer a minor technical detail — it is a strategic climate decision.

‍

10. Conclusion

SF₆-based switchgear carries a hidden but significant carbon footprint, driven by the extreme global warming potential of the gas itself. Even small leakage rates translate into tonnes of CO₂-equivalent emissions over an asset’s lifetime.

SF₆-free GIS fundamentally changes this equation. By eliminating fluorinated gases entirely, it removes one of the most potent greenhouse gas sources from medium-voltage infrastructure — without compromising safety, performance, or reliability.

For utilities, EPCs, and industrial operators serious about decarbonization, SF₆-free switchgear is not just a compliance solution — it is a climate-impact reduction measure.