Sulphur Hexafluoride: Does its long-term impact outweigh its benefits?

In a drive to combat climate change, coal-fired power stations are steadily being replaced with mixed sources of alternative power generation including wind, solar and gas. This has consequently increased the connections to the electricity grid and the use of switches and circuit breakers (also known as switchgears) containing Sulphur Hexafluoride (SF).

SF is a colourless, odourless, non-flammable gas that is used widely across the industry to insulate high voltage switchboards. From large power stations, wind turbines, electrical sub-stations in towns and cities and within the medical industry, SF has been the go-to dielectric insulating material. This is due to high electrical insulating properties, non-flammability, non-toxicity, low maintenance and competitive cost.

However, the significant downside to using the gas is that it holds the highest global warming potential of any known substance. Just one kilogram of SF warms the Earth’s core to the same extent as 24 people flying return from London to New York.

According to the Intergovernmental Panel on Climate Change (IPCC), SF has a global warming potential (GWP) of 23,900 times that of CO2 based on a 100-year horizon and an atmospheric lifetime of 3,200 years. This makes SF the most potent greenhouse gas.

A 2017 study from the University of Cardiff found that across all transmission and distribution networks, the amount used was increasing by 30-40 tonnes per year.

As a result, SF-specific regulations have now been put in place and companies must operate and maintain SF switchgears in a responsible manner. The HSE outline rigorous management of switchgears on a closed cycle to avoid deliberate gas release into the atmosphere and monitoring any emissions during operation.

Early detection of SF is key and Shawcity has a range of products designed to monitor atmospheric changes and spot checks for SF leaks.

The SF Leakmate from Ion Science is an easy-to-use handheld instrument that acclimatises to its surroundings and alarms when SF is present. As well as audio and visual alarms, it also has a LED bar graph display, allowing estimation if a small, medium, or large leak is being detected. Perfect for checking seals and tightness of components before investigating further with a more sensitive device.

Like the SF Leakmate, the GasCheck G detector is designed for the search and location of gas leaks. GasCheck G provides effective detection of almost any gas or gas mixture and specifically SF. Robust and reliable, the detector gives stable, repeatable readings.

The GasCheck G leak detector automatically zeros to the ambient air around it, when switched on and is ready to detect immediately. The instrument's easy to use graphical interface and intuitive keypad allows for simple function, selection and adjustment.

The next stage of detection would involve a monitor such as the SF LeakCheck P1, which has ultra-high sensitivity to SF and can detect leaks down to 1 x 10-8ml/sec.

Ideal for the location, leak testing and measurement of SF in high voltage electrical switchgears, the detector is unaffected by large leaks and will remain uncontaminated even after exposure to 100% SF gas.

Finally, the SF AreaCheck P2 is designed for fixed continuous area monitoring that can rapidly detect low level SFleaks. The instrument set up can be achieved easily via a computer or network interface, allowing optimal protection from unauthorised access. It has an exchangeable SmartSensor with a 12-month life span offering low maintenance and around the clock detection.

All of the above options are available from Shawcity who can provide free support, advice and training for the lifetime of the instrument. 

To speak to one of our sales team or to arrange a site visit or demo, call 01367 899419 or email:

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