Wind turbines, both on-shore, and off-shore rely on electrical switchgear for safety. Mandating switchgear that is free from the greenhouse gas, SF6 will keep net-zero ambitions intact as more turbines are built
Kenya has a viable wind energy resource that aims to generate 2,036 MW of wind power, or 9% of the country’s total capacity, by 2030. According to the Energy and Petroleum Regulatory Authority (EPRA), 73% of the country experiences wind speeds of 6 m/s or higher at a hundred meters above ground level.
Using wind power to bolster energy security is a positive environmental choice and as a key plank of future energy strategies in many countries, construction of wind farms will continue apace. Kenya is not left behind as it stands tall amongst African countries when it comes to wind energy production. Its claim to fame is the Lake Turkana Wind Plant (LTWP), the largest of its kind on the continent.
Wind farm technology is well understood, but less widely recognized is the global-warming potential of the switchgear that provides overcurrent and short circuit protection in turbines. Unless it is what’s known as SF6-free switchgear, it can leak climate-damaging gas.
At the root of the problem is Sulphur Hexafluoride, more commonly known as SF6, which is still used widely as an insulator and arc extinguisher in switchgear. Comprising a sulfur atom and six fluorine atoms, each SF6 molecule is an environmental menace: just 1 kg is equivalent to 23,500 Kg of CO2 in terms of global warming.
Mandating SF6-free switchgear in renewable technologies – solar arrays, as well as wind farms – will avoid derailing net-zero ambitions as the push for clean, secure energy intensifies.
Kenya is set to gain more wind farms as the East African country moves to increase and diversify its clean energy resources. Moving away from traditional methods of generating power such as thermal, to clean methods of producing the same using readily available wind resources, which is more innovative and cuts carbon emissions.
Why does the industry use SF6?
Scientists first discovered how to make SF6 in industrial quantities during the 1960s – only a small amount occurs naturally. Stable, odorless, and colorless, it was used in applications as varied as insulating windows and providing the ‘bounce’ in tennis balls and vehicle tires.
However, it was not long before the environmental dangers of fluorine gasses became apparent, and governments started phasing them out. The EU’s legislative response to what became known as F-Gasses included banning SF6 in every application except switchgear, which was exempt because of its role as a critical safety feature.
This exemption has had unfortunate consequences. SF6 is undoubtedly a good insulator, widely and readily available, which means that far from fading away, its use in electrical switchgear has increased. Counterproductively, it has even found its way into applications such as wind farms which are intended to reduce global warming.
Now, however, the tide is turning, and the EU is set to announce an end to the exemption which is likely to come into effect across many countries during the mid-to-late 2020s.
Renewables could make the difference
Renewable generation is driving growth in the switchgear market which is why a fast phase-out of SF6 after the likely lifting of the exemption is essential. Renewable assets up the stake in more ways than one: there are set to be more of them, and they require more frequent switching because of the way they work.
Fortunately, well-proven alternatives are already available for up to and including 24 kV. Eaton pioneered the use of alternative insulation technologies at much the same time as SF6 was discovered, back in the 1960s.
Reasons for optimism
Electrical industry professionals can do much to prevent further SF6 emissions adding to what is already a worrisome burden on the environment. Governments can play their part by driving forward policy to prevent further use of SF6 in applications including switchgear.
As it is easier to specify SF6-free switchgear on new projects than encourage the replacement of switchgear on existing projects, the boom in renewable technology could be a real opportunity to embed SF6-free know-how in the electrical industry. If there is a good time to go SF6-free, that time is surely now.
The author is Eastern Africa Regional Manager at Eaton Electric Ltd.