[HN Gopher] Reinventing circuit breakers with supercritical CO2
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Reinventing circuit breakers with supercritical CO2
Author : rbanffy
Score : 95 points
Date : 2025-06-15 23:01 UTC (1 days ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| gnabgib wrote:
| The article's title doesn't seem to be accurate.
|
| - It doesn't exist (there is mention of a prototype - but that's
| not really a debut, all the images in the article are generic).
|
| - The $3.9M funding ended May 18th
| https://arpa-e.energy.gov/programs-and-initiatives/search-al...
| and there doesn't seem to be a related paper yet (other than this
| IEEE "maybe" from April)
|
| - The project is (unfortunately) called _TESLA: Tough and
| Ecological Supercritical Line Breaker for AC_ 2022:
| https://www.sf6andalternativescoalition.org/wp-content/uploa...
| tomhow wrote:
| OK, we retitled it to a more modest subtitle from the article.
| idiotsecant wrote:
| At first I thought that would be wildly impractical but CO2 goes
| supercritical at just shy of 90degF and a little over 1kpsi.
| Those kinds of pressures are pretty well unknown in a substation,
| but occur all the time in refineries and the like. It's basically
| just a pressure vessel with a relatively mild heater requirement.
| Eminently doable. I think we will probably see these deployed in
| the next few decades. SF6 is an amazing material but really,
| really horrible as a greenhouse gas.
| PaulHoule wrote:
| For years they had an SF6 tank in my building because somebody
| had a wind tunnel (the first photo)
|
| https://batl.mae.cornell.edu/facilities/
|
| the machine is still there but they took out the SF6 tank.
| sokka_h2otribe wrote:
| Super critical c02 is a regular extraction process method for
| certain molecules! You can find it in a number of laboratory
| applications. Anyway, yes, doable - essentially for the reasons
| you mention. But also literally done at the moment, for the
| general extraction process capabilities of supercrit CO2
| angus-g wrote:
| Here's a guy playing with a supercritical CO2 pressure vessel
| on a table (seems a little brave to be shaking something at
| such high pressures!)
| https://www.youtube.com/watch?v=2d7RGQMCX24
| Full_Clark wrote:
| > The work may be niche, but the impact could be high. About 1
| percent of SF6 leaks from electrical equipment. In 2018, that
| translated to 8,200 tonnes of SF6 emitted globally, accounting
| for about 1 percent of the global-warming value that year.
|
| This figure is for the electricity sector only, not overall
| global emissions. Still, considering the sheer volume of CO2
| puffing up from power stations, it's impressive that the normal
| operation of SF6 breakers accounts for an integer percentage of
| their GHG impact.
|
| ----
|
| Global emissions were 53 Gt CO2 equivalent in 2023 [0]. 38% of
| CO2 emissions are attributed to the electricity sector in 2023.
| [1] This figure seems to be strictly CO2, not including other
| GHG, and I can't quickly find a sector-by-sector breakdown for
| that year. Per IPCC reports in 2022, electricity production and
| heating accounted for 34% of global GHG in 2019 [2], so for back-
| of-the-envelope math, it's reasonable.
|
| Per the article, the GHG impact of SF6 is 25k CO2, so 8.2k tons
| SF6 emitted annually is 205 million tons CO2e. This is 0.39% of
| 53 Gt CO2e (the global value), or nearly exactly 1% of the
| electricity sector's 38% share.
|
| [0] https://www.statista.com/statistics/1285502/annual-global-
| gr... [1] https://www.statista.com/statistics/1129656/global-
| share-of-... [2] https://www.epa.gov/ghgemissions/global-
| greenhouse-gas-overv...
|
| edit: replaced typos of C02 with correct CO2
| kragen wrote:
| Thank you for doing these calculations! 0.39% of anthropogenic
| global warming is surprisingly large, but it doesn't sound like
| a big impact to me. I mean, it sounds like about the same
| greenhouse effect impact as the San Bernardino metropolitan
| area (5 million people) or the Chongqing metropolitan area (12
| million people).
|
| Retric: I regret not having responded in time to your comments,
| which I agree with.
| Full_Clark wrote:
| In terms of impact, it doesn't sound major, I agree. But it's
| still work that will need to be done. As industry and
| transport become more electrified, and electric generation
| gets decarbonized, impacts like high-multiple GHG gases will
| become a bigger and bigger share of CO2e still happening.
|
| Atmospheric CO2 is already too high to avert terrible long-
| term impacts of global climate change. Unless we manage to
| make massive cost reductions for atmospheric CO2
| sequestration, weaning entirely off of fossil fuels will not
| be sufficient to avoid climate change impacts if we still add
| long-lived GHG molecules to the atmosphere. (SF6 has an
| atmospheric lifetime on the order of 1000s of years.)
|
| Think of it like the tide going out in a rocky bay. As the
| water level recedes, rock pillars that used to be too deep
| underwater to worry about now are close enough to the surface
| to cause you trouble. On the other side of the same coin,
| putting in the work to clear them helps give you as big a
| space to operate in as you had before.
| kragen wrote:
| > _Unless we manage to make massive cost reductions for
| atmospheric CO2 sequestration,_
|
| We will. The main reason atmospheric carbon capture is
| expensive is that it requires a lot of energy, and the cost
| of energy is falling through the floor because of cheap
| renewables. Expensive high-efficiency chemistries for
| carbon capture will cede to simpler, energy-hungrier
| chemistries, the ultimate reductio ad absurdum being
| something like soda lime. Soon enough synfuel from
| atmospheric carbon capture will be an attractive
| alternative to fossil fuels for transport (within 15
| years), and then it's just a question of capturing the
| combustion products from the fuel. We may need to start
| adding high-multiple GHGs to the atmosphere to compensate
| for carbon dioxide we remove to make plastic. Hopefully
| shorter-half-life GHGs than sulfur hexafluoride, though.
|
| The US has taken a very aggressive policy stance against
| renewables and in favor of fossil fuels, but ultimately it
| can't prevent the inevitable. If it continues to punish the
| importation of renewable energy equipment, US subjects will
| import cheap synfuel, or, failing that, they'll import
| electrolytic iron, zinc, or magnesium to use as fuel, from
| countries like Chile, China, and Dubai.
| toomuchtodo wrote:
| I am bullish on the rapid global uptake of low carbon
| electrical generation (global solar PV deployment alone
| is almost at 1 TW/year), but bearish on carbon
| sequestration being viable unless sucking the CO2 out of
| the ocean (due to energy required via atmospheric
| capture). It's not just energy required, but how much
| carrier (whether that's air or water) you need to process
| per unit of CO2 removed.
|
| _Stanford Study: Renewable Energy Beats Carbon Capture
| on Cost and Climate Impact_ -
| https://carbonherald.com/stanford-study-renewable-energy-
| bea... - June 11th, 2025
|
| _Energy, Health, and Climate Costs of Carbon-Capture and
| Direct-Air-Capture versus 100%-Wind-Water-Solar Climate
| Policies in 149 Countries_ -
| https://pubs.acs.org/doi/10.1021/acs.est.4c10686 |
| https://doi.org/10.1021/acs.est.4c10686
|
| _Climeworks' capture fails to cover its own emissions_ -
| https://heimildin.is/grein/24581/ - May 15th, 2025
| kragen wrote:
| I'm skeptical of the Heimildin article, because it
| contains obvious factual errors:
|
| > _equivalent to almost four times Iceland 's electricity
| production, which is about 20 terawatts per year._
|
| You can't measure electricity production in terawatts per
| year; you can measure things like solar panel deployment
| speed in those units, as you correctly did. This makes me
| wonder how many other factual errors I failed to spot in
| the article.
|
| But, yes, we should not expect atmospheric carbon capture
| to be economically feasible yet, and when it is, we
| should expect most companies that attempt it to fail,
| just as most solar panel companies have failed. But
| remember that solar energy is free when the sun is up;
| there's no economic benefit to curtailing your electric
| production because your batteries are full. So we should
| expect vastly more energy-intensive approaches than
| Climeworks' to be viable.
|
| Atmospheric carbon capture isn't an alternative to
| renewable energy. It's what you do in response to the
| much lower energy costs resulting from renewable energy,
| and to reverse the damage already done.
| Full_Clark wrote:
| > Expensive high-efficiency chemistries for carbon
| capture will cede to simpler, energy-hungrier
| chemistries, the ultimate reductio ad absurdum being
| something like soda lime
|
| I haven't looked into the topic much at all but that does
| resonate. It reminds of the way solar farms are becoming
| less fine-tuned (e.g., no sun-tracking tilt motors
| anymore) as panel costs drops through the floor.
| burnished wrote:
| But large enough that if you did similar 100 times you'd
| almost halve it!
| gsf_emergency wrote:
| Not just academic: Hitachi have already _deployed_ a different
| gas (mix) last month
|
| https://www.hitachienergy.com/news-and-events/press-releases...
| Mengkudulangsat wrote:
| Isn't SF6 very dense?
|
| Why would its greenhouse warming potential matter if it's never
| going high up into the atmosphere in the first place?
| Metacelsus wrote:
| It will mix throughout the troposphere like any other gas.
| pfdietz wrote:
| Gases in the atmosphere separate by molecular weight only at
| very high altitude, above the "homopause". This is from 80 to
| 120 km. Below that altitude, turbulence remixes gases faster
| than they can separate.
| robocat wrote:
| SF6 is a significant greenhouse gas but what is troubling is that
| "SF6 is a very stable compound in the atmosphere, with an average
| residence time of about 3,200 years".
|
| From
| https://www.energynetworks.org/assets/images/Resource%20libr... :
| It is estimated that SF6 currently contributes about 0.2% of the
| global warming potential of the annual greenhouse gas emissions
| in the UK. SF6 in electrical equipment is contained
| and not intentionally released during operation. Recycling of SF6
| from electric power equipment, using commercial gas reclaimers,
| is becoming common practice [in the UK].
|
| SF6 huff and talk is fun though:
| https://youtu.be/d-XbjFn3aqE?t=29s
|
| > About 1 percent of SF6 leaks from electrical equipment. In
| 2018, that translated to 8,200 tonnes of SF6 emitted globally,
| accounting for about 1 percent of the global-warming value that
| year.
|
| There's something wrong with that figure. Global production was
| about 7500 tons in 1995, and countries have been trying to use
| less since then. 50% of production used in OEM equipment and 31%
| by Electric Utilities (maybe recharging breakers after
| inspections?). See:
| https://www.epa.gov/sites/default/files/2016-02/documents/co...
| tigerlily wrote:
| Hey CO2 is still greenhouse. I guess not while it's contained and
| in its supercritical state, but if it's released to atmosphere
| then gas it will be.
|
| Excited for the guys at Chalfont to test this out eventually,
| another fun chance to see if something goes boom :)
| Aurornis wrote:
| > Hey CO2 is still greenhouse
|
| SF6 has 25,000 times the 100-year global warming potential as
| CO2.
|
| You'd have to accidentally vent thousands of these breakers to
| equal the same global warming potential as one SF6 breaker
|
| When it comes to topics like this, reducing it to a binary is-
| or-isn't greenhouse gas is the wrong way to look at it.
| colechristensen wrote:
| These breakers are carbon neutral because the CO2 comes
| either straight from the atmosphere or is harvested from
| sources that would otherwise be vented to the atmosphere.
| tigerlily wrote:
| I was responding to the badly editorialised title which read
| "without greehouse gases". I think I am on pretty solid
| ground here, the title misled.
|
| Now the title reads "Reinventing". Is this a pejorative?
| Engineers make firsts too. TFA's title works just fine.
| excalibur wrote:
| This. I don't doubt that the new design is a vast emissions
| improvement. But the title clearly says without greenhouse gas,
| and CO2 is the poster child for greenhouse gases.
| tigerlily wrote:
| The thing that baffles me is folk in this community so
| willingly put their critical thinking skills to one side to
| downvote your post.
| numpad0 wrote:
| SF6? The DRIE etchant gas?
| b3orn wrote:
| Yes, but for DRIE you need plasma so you ionise it.
| pfdietz wrote:
| Another fluorinated greenhouse gas used in etching is nitrogen
| trifluoride. It's second only to SF6 in its GWP.
| buildsjets wrote:
| I'm certain that I have seen CF3I (trifluoroiodomethane) used or
| proposed to be used as an arc quenching agent in HV breakers. It
| also may soon be replacing Halon (CF3Br, bromotrifluoromethane)
| for aircraft fire extinguishing.
| mikewarot wrote:
| Interesting but just not practical, especially when there is a
| well proven system in use.
|
| I get that we don't want SF6 released unnecessarily, but grid
| components need to be reliable, and a breaker that could turn
| into bomb if it loses temperature control seems loke a very bad
| idea.
|
| PS: I had a small amount of SF6 injected into my eyeball a few
| years ago, and it helped save my sight.
| hoseja wrote:
| Is there a word for this? Subpar lead-free solders and
| piezoelectrics, subpar coolants etc. Greenshittification?
| morsch wrote:
| Engineering involves trade-offs. It's easier when you don't
| consider all of them. But it's poor workmanship.
| wkat4242 wrote:
| One of the drawbacks of SF6 is said to be the protective
| clothing. But it sounds like CO2 at almost-liquid pressures will
| be even more dangerous to an unprotected human.
|
| Though I looked it up and the pressure isn't as high as I thought
| at around 72 bar. Still enough to make weak parts explode though.
|
| In other words, I don't think this will be the end of protective
| gear.
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