Electrical switchgear releases greenhouse gases
Posted on 17th September 2019
The BBC has reported an increase in leaks of SF6 (sulphur hexafluoride), widely used in the electrical industry to prevent short circuits that could lead to fires.
The gas is cheap and non-flammable and is effective for insulating medium- and high-voltage electrical installations. However, it has around 23,000 times more global warming potential than carbon dioxide (CO2) and its effect in the atmosphere is likely to last for hundreds of years
According to research, the environmental impact of these leaks across Europe in 2017 was equivalent to an extra 1.3 million cars on the road (or 6.73 million tonnes of CO2). Although use of SF6 was banned in Europe in 2014 for all other purposes it is still allowed in the electrical industry, which is uses about 80% of all the SF6 produced.
Around the world, the use of SF6 is expected to grow by 75% by 2030. Because SF6 is a synthetic gas, it isn't neutralised in the environment. To reduce its impact on the climate it will need to be replaced and safely destroyed.
Why use a global warming gas?
Our efforts to reduce global warming have led to increased use of alternative sources of energy such as wind, solar and gas. As a result, there are many more power sources connected to the electricity grid, all needing electrical switches and circuit breakers to prevent accidents and damage to equipment.
These safety devices, or switchgear, use SF6 to reduce the impact of electrical arcs that can otherwise cause short circuits and lead to fires.
How are SF6 leaks measured?
Around one million kilograms of SF6 are currently used in the UK’s power network. The University of Cardiff found that 30 to 40 extra tonnes of SF6 was used each year; a pattern that was mirrored across Europe.
Although new switchgear equipment is much less likely to leak, older equipment remains in use. Leaks can happen during equipment manufacture, refilling and recycling of the gas.
Worryingly, concentrations in the atmosphere are being detected that are 10 times higher than they should be, according to the reports of countries that declare figures for their use of SF6.
What happens next?
In the UK, energy companies are working with the government to reduce leaks and to find alternatives.
Currently, other suitable options for high-voltage uses haven’t been identified and tested. However, for medium-voltage uses there are alternatives, but they are not yet widely used.
However, at one of world's biggest wind farms in the North Sea that produces enough electricity to supply half a million homes, none of the turbines use SF6 gas. Instead, a combination of air and vacuum technology will be used in the turbines, although the substation they are connected to will still use SF6
Tagged as: electrical installation
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