2024-04-03 17:30:07
diPaolo Virtuani
Sulfur hexafluoride is an insulator for high voltage electricity. It remains in the atmosphere for over a thousand years, its heating power is 24 thousand times that of carbon dioxide
Sulfur hexafluoride, the chemical formula is SF6: it is used in many industrial activities. It does not exist in nature, it is a transparent, non-toxic, odorless gas and is generally used in liquid form as an insulator in power plants, high voltage cabins and transformers. Its problem is that, if dispersed into the atmosphere, before degrading it remains in the air for a period between one thousand and 3,200 years and its greenhouse gas warming power over a century is 24,300 times greater than that of CO2 . Put more simply: one gram of SF6 released into the atmosphere – and electrical transformers unfortunately leak a lot of this substance – produces the same result as 24.3 kilograms of carbon dioxide. Multiplied by approximately 20, because the duration of the stay in the air must be considered. In practice: one gram of sulfur hexafluoride produces the same damage as 500 kilos of CO2.
Emissions boom in China
An international study conducted by researchers from MIT in Boston, the Universities of Beijing, Bristol and Fudan and other institutes, financed by various agencies including NASA, published in Nature Communications, found that from 2011 to 2021 in China emissions of SF6 increased from 2,600 tonnes per year (equal to 34% of global emissions of this substance) to 5,100 t/year (equal to 57%). The researchers correlate this surge with the sharp increase in Chinese electricity production, particularly in the less populated but rapidly developing western provinces.
Should we worry?
How much SF6 is there in the atmosphere? In reality not much, today the most accurate measurements – comparing six specialized stations distributed throughout the world (here the monitoring of all “minor” greenhouse gases, therefore excluding methane and carbon dioxide) – find a content of 11.5 ppt. It means that there are 11.5 grams of SF6 per thousand tons of air. Not much, if you consider that in 2023 there were 420 grams of CO2 in a single ton of air. But the increase in SF6 in the air in recent years has been dramatic. If you consider that in 2012 the content was 7.6 ppt, the increase was over 50%.
April 3, 2024 (modified April 9, 2024 | 6:51 pm)
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