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  • If were going to stave off the worst impacts of climate change,

  • were going to have to break our dependency on greenhouse gas emitting energy sources like fossil fuels.

  • But could a switch to more renewable sources like wind and solar power

  • actually emit more of the most potent greenhouse gas there is?

  • The gas in question is sulfur hexafluoride, or SF6,

  • and as you might imagine, each molecule is made up of one sulfur atom and six fluorine atoms.

  • If youre a geek like me who scours the internet for science memes,

  • and I have reason to believe that you are,

  • you may have seen some of the cool party tricks sulfur hexafluoride is used for.

  • It’s odorless, colorless, and heavier than air, so if you inhale it it lowers your voice,

  • sort of like bizarro-helium. It’s also not very reactive,

  • and it can prevent fires since sulfur hexafluoride displaces the air that feeds the flames.

  • These properties also make it useful for industrial applications,

  • namely for preventing short circuits and fires in high voltage electrical switches and circuit breakers.

  • This type of safety equipment, also known as switchgear,

  • is necessary to prevent serious accidents,

  • and electric grids need more of them as we add more sources of energy.

  • So as we add more renewables, were also upping our use of sulfur hexafluoride.

  • One UK study found that their electric transmission and distribution systems are increasing the use of SF6

  • by 30-40 metric tons every year,

  • and worldwide were expecting to use 75% more of it by 2030.

  • And therein lies the great irony.

  • Sulfur hexafluoride is a fluorinated gas, a group of gasses with high global warming potentials.

  • And even among this group, SF6 is the most potent greenhouse gas of them all,

  • with 23,500 times the warming potential of CO2.

  • And the molecule is synthetic, so it isn’t broken down or absorbed naturally,

  • meaning it persists in the atmosphere for thousands of years.

  • That all means that a little bit of SF6 can have a disproportionately big impact.

  • Of course, it’s not as though were intentionally adding sulfur hexafluoride to the atmosphere,

  • unless youre using it to make your voice deeper.

  • But that doesn’t mean it doesn’t leak from its containers and into the environment,

  • and when it does it’s hard to notice.

  • Like I said, the gas is odorless and colorless.

  • According to NOAA, the concentration of sulfur hexafluoride in our atmosphere

  • has more than doubled in the past two decades.

  • SF6 emissions in 2017 in Europe were the equivalent of adding 1.3 million cars to the road.

  • So should we be worried?

  • Does the increase in sulfur hexafluoride make all our efforts to switch to renewables for nought?

  • Thankfully, no.

  • In 2017, SF6 leaks accounted for just 0.11% of the greenhouse gasses emitted from the UK.

  • Still, regulators and the electric industry are working to find alternatives.

  • For medium voltage use cases, there are other materials that could take its place,

  • but SF6 is still the go-to choice for high voltage applications because it’s proven to work and it’s cheap.

  • Attempts to regulate it have been met with strong political opposition from companies

  • that were unwilling to change.

  • Still, some companies are finding ways to do without it:

  • Siemens, for example, developed high voltage switchgear that is SF6-free.

  • Scottish Power Renewables is building a wind farm that will use clean air and vacuum technology

  • inside the turbines to eliminate the need for sulfur hexafluoride.

  • But where it can’t be eliminated, better handling, training, recycling and leak containment is key.

  • And the good news is, SF6 emissions have been dropping year over year,

  • even as electric grids use more of it.

  • Alternative energy sources like wind and solar

  • can finally move us away from environmentally damaging fossil fuels

  • by cutting down on the CO2 we emit.

  • As we work towards more climate-neutral power sources,

  • it’s important that the grid that transmits and distributes that power helps us achieve a sustainable future, too.

  • The problem with fossil fuels is they take carbon that was locked away underground and release it into the air.

  • So what if we took that CO2 and stuffed it back into rocks?

  • Maren has a video on that here.

  • If you like this video, make sure you subscribe to Seeker for all the hot takes on our warming planet.

  • And as always, thanks for watching.

If were going to stave off the worst impacts of climate change,

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二氧化碳不是最糟糕的溫室氣體,遇到SF6 (Carbon Dioxide Is Not the Worst Greenhouse Gas, Meet SF6)

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    林宜悉 發佈於 2021 年 01 月 14 日
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