By Marcel Buckner, Power Distribution Business Development Manager, Africa, Eaton
Being a good corporate citizen means that businesses place people first, respective of their employees and the communities they operate in. Sulphur hexafluoride (SF6), routinely used in electrical switchgear poses a significant risk to both human health and the environment based on possible adverse operating conditions, possible leakage, and inappropriate disposal of the equipment at the end of its life cycle.
Sulphur hexafluoride (SF6) is a man-made colourless, odourless gas that was introduced to replace oil as an extinguishing media in electrical switchgear in the early ’70s. Initially, it was considered innovation as an insulating and circuit breaking medium in switchgear. As time went by, and due to the past lack of alternatives, it is included in many existing energy installations. In the meantime, SF6 was identified by the Kyoto Protocol by the Climate Change Convention, as one of the six most harmful greenhouse gases and its impact on climate change was highlighted.
SF6 has been used throughout the electrical industry for decades. Today, cost-effective, state of the art and energy efficient SF6 free alternatives are available. However, the cost of replacement and responsible recycling has prevented many users from replacing their existing SF6 contained switchgear with SF6 free alternative gear. In certain business segments notably Utilities minimising or eliminating SF6 emissions is increasingly prioritised.
Irresponsible disposing of SF6 contained equipment is another cause for concern. Specialised facilities are required to ensure safe disposal, facilities that are not readily available in every country, and costs to do so are high. In South Africa, many people recycle waste products to earn an income and it is in these activities that the threat to human life can lie.
SF6 is used in electrical switchgear installations to protect against arcs and other electrical discharges, and when heated above 300 degrees centigrade toxic by-products can be formed during these incidents.
The reactive by-products generated during spark discharges, partial discharges, switching arcs, or failure arcs can take the form of gases or powders. They can include sulphur dioxide, thionyl sulphide, hydrogen fluoride, and disulphur decafluoride, amongst others.
The by-products have varying effects on people, known to include irritation to the eyes, nose, and throat, pulmonary oedema and other lung damage, skin and eye burns, bronchitis, and skin rashes. The impact on the environment is equally devastating and will impact generations to come –not just on-site workers or unsuspecting folk dismantling gear on dumpsites. One kilogram of SF6 (most switchgear contain a few kilograms), released into the atmosphere, is equal to 23 500 kilograms of CO2.
Apart from the considerable potential harm to human life, the cost of SF6 ownership is high, as owners of SF6 switchgear may need to keep records of equipment owned, conduct regular pressure inspections, possibly conduct refills, carry out advanced training for employees and supply them with appropriate personal protective equipment too. The end-of-life costs vary and can be greater than 50% of original CAPEX costs.
It’s clear that preventing damage to the environment and danger to human life, by replacing SF6 switchgear with smarter alternatives, must take priority. Currently available SF6-free switchgear has a Low Total Cost of Ownership (TCO), with very competitive initial costs, absolute minimal costs during service life, and extremely low end of life disposal costs.
For example, Eaton’s Xiria switchgear is maintenance-free and compact, with a high level of operational safety. Most importantly, it’s free of SF6, and it is a state of the art design that is combined with solid insulation with clean dry air at ambient pressure in a hermetically sealed compartment that protects primary parts and operating mechanisms from environmental factors such as moisture, dirt, dust, and salt, and other kinds of pollutants.
When faced with such clear insights into the human and environmental costs of SF6– based switchgear, it really does become almost impossible to avoid replacing it with equipment that will protect lives and preserve our planet for the survival of future generations.