Aside from simply being a greenhouse gas (and not to mention how it is produced - countries use weather balloons filled with hydrogen but the machinery to produce H on site is expensive, and the handling procedures are complex, see https://www.fp2fire.com/hydrogen-balloon-inflation/), hydrogen is a reactive species that tends to deplete hydroxyl radical molecules (forming H2O), which also happens to be what you need to produce H2SO4.
So if you started using hydrogen you would: - have even more and possibly unknown reaction capable of modifying ozone (meaning the link to our study on ozone depletion you have on your website would be irrelevant), and potentially rendering your SO4 formation processes inefficient - risk balloon safety - normally you need to make sure you’re only putting H in your balloon (see link above). I doubt balloons have been tested with such a mixture inside, and that some form of reaction wouldn’t occur. - assuming you use 1g of H for 1g of sulfate, as Russell has already said, at scale you would emit in the stratosphere a quantity of hydrogen similar to current estimates for the whole hydrogen leak rate of a whole hydrogen economy in 2050 (source https://www.energypolicy.columbia.edu/research/commentary/hydrogen-leakage-potential-risk-hydrogen-economy#:~:text=The%20leakage%20rate%20stands%20between,%242%2Fkg%2DH2). But if that hydrogen was released in the stratosphere directly its GWP would be much higher than that estimated from current surface leaks (https://acp.copernicus.org/articles/22/9349/2022/) So while doing stunts with Helium and sulfate you produce yourself may be seen as potentially harmless, without proper studies doing the same with hydrogen would be outright insane and hazardous. Onus would be on you to prove otherwise before outdoor tests. > On 30 Dec 2022, at 11:22, Luke Iseman <[email protected]> wrote: > > Russell, > > My cofounder tweeted the "trade secrets" claim in error (see further up in > this thread). > I agree helium is a valuable resource and intend to switch to hydrogen in the > future. > I also don't have religion around balloons: if anyone has a surplus > stratospheric aircraft sitting around along with a venue from which to fly > it, that's probably a better value then balloons;) > > -------------------- > Luke Iseman > lukeiseman.com <http://lukeiseman.com/> > > > > On Thu, Dec 29, 2022 at 6:07 PM Russell Seitz <[email protected] > <mailto:[email protected]>> wrote: >> Luke, Make Sunsets has tweeted invoking "trade secrets ' in denying simple >> requests to quantify how much helium is needed per >> " cooling credit". >> This lack of transparency cannot stop anyone , policy analysts included from >> running the numbers . >> >> Dimensional analysis based on handbook and commercially disclosed values >> of the physical constants of air, helium and SO2 indicates that you can at >> best hope to lift 1.01 Kg per STP cubic meter of 97% pure balloon grade He. >> >> Since SO2 vapor's molecular weight makes it over twice as dense as air ( >> ~64/29), even if if the dead weigh of the balloon and its telemetry are >> completely disregarded it will still take a tonne or more of helium to >> loft a tonne of aerosol feedstock to stratospheric elevation. >> >> As you must be aware, the short supply of helium ( the US strategic reserve >> acquired after WWII was largely sold off by 2021) has already quadrupled >> its cost., and at present , annual global production is below100,000 >> tonnes and recoverable reserves stand at around 30 million tonnes globally. >> >> Using NOAA's numbers: >> https://research.noaa.gov/article/ArtMID/587/ArticleID/2756/Simulated-geoengineering-evaluation-cooler-planet-but-with-side-effects >> it is clear that your scheme would require lofting of a megatonne or more >> of SO2 a year per degree K of cooling: which is not only an order of >> magnitude more that present production can bear, but enough to completely >> deplete known reserves and resources by 2050. >> >> Finally, US helium is almost exclusively a byproduct of natural gas >> production , and so entails substantial release of methane and other >> hydrocarbons that are greenhouse gases more powerful than CO2 >> >> On Wednesday, December 28, 2022 at 6:09:51 PM UTC-5 [email protected] >> <mailto:[email protected]> wrote: >>> Thanks Andrew, Olivier, Bala, and everyone else for diving in with >>> critiques here. I'm a cofounder of Make Sunsets and want to clarify a few >>> things: >>> >>> Honesty: >>> We have no desire to mislead anyone. If we make a mistake (which we will), >>> we'll correct it. >>> Radiative Forcing: >>> I didn't make this "gram offsets a ton" number up. It comes from David >>> Keith's research: >>> "a gram of aerosol in the stratosphere, delivered perhaps by high-flying >>> jets, could offset the warming effect of a ton of carbon dioxide, a factor >>> of 1 million to 1." >>> <https://keith.seas.harvard.edu/news/whats-right-temperature-earth> >>> and, again: "Geoengineering’s leverage is very high—one gram of particles >>> in the stratosphere prevents the warming caused by a ton of carbon >>> dioxide." >>> <https://longnow.org/seminars/02015/feb/17/patient-geoengineering/> >>> By stating "offsetting the warming effect of 1 ton of carbon for 1 year," I >>> was trying to be more conservative than Professor Keith. I am correcting >>> "carbon" to read "carbon dioxide" on the cooling credit description right >>> now, and I'm adding a paragraph at the start of the post stating that >>> estimates vary, but a leading researcher cites a gram offsetting a ton. >>> For the several hundred dollars of cooling credits we've already sold, I'll >>> be providing evidence to each purchaser that I've delivered at least 2 >>> grams per cooling credit. >>> Olivier, or anyone else: I'd be happy to post something by you to our blog >>> explaining what you estimate the radiative forcing of 1g so2 released at >>> 20km altitude from in or near the tropics will be and why. I will include >>> language of your choosing explaining that you in no way endorse what we are >>> doing. >>> I very much hope to get suggestions from this community on instrumentation >>> we should fly to improve the state of the science here. Again, I'm happy to >>> do this with disclaimers about how researchers we fly things for are not >>> endorsing our efforts. Or even without revealing who the researchers are: >>> we'll fly test instruments and provide data, no questions asked:) >>> Telemetry: >>> My first 2 flights had no telemetry: in April, this was still in >>> self-funded science project territory. After burning some sulfur and >>> capturing the resultant gas, I placed this in a balloon. I then added >>> helium, underinflating the balloon substantially, and let it go. There is >>> technically a slim possibility that neither of these balloons reached the >>> stratosphere, as I acknowledged to the Technology Review reporter. I will >>> add Spot trackers to my next flights. These cut out at 18km, so I'l be able >>> to confirm that I achieve at least this altitude. If (and this is a big if) >>> I'm able to recover the balloons, I'll have a lot more data from the flight >>> computer >>> <https://www.highaltitudescience.com/collections/electronics/products/eagle-flight-computer>. >>> I will eventually switch to Swarms >>> <https://www.sparkfun.com/products/19236?utm_campaign=May%206%2C%202022&utm_medium=email&_hsmi=212205037&_hsenc=p2ANqtz-9EyQOQ6C-9XuSOHa7CggOC8Pf2tEow_Fppo5pXgTHO8-7gV-aHrrYpnPcliws6Ju8j2PBAX3Tkog0oVpwk8XqWX2xo0w&utm_content=212206499&utm_source=hs_email>, >>> which should let me transmit more data regardless of balloon recovery. >>> Pricing: >>> Bala, you're totally right that this should be priced much lower. We're >>> trying to make enough with our early flights to stay in business until we >>> get meaningful traction with customers, and we plan to eventually drop >>> prices to $1 per ton or less. >>> Reuse: >>> We are not yet reusing balloons, and Andrew is correct that latex UV >>> degradation will limit our ability to do so with weather balloons. Given >>> that balloon cost is our main expense per gram, even a few uses per balloon >>> will dramatically improve the economics here. >>> >>> I expect to disagree with some of you, but I hope we can do so politely and >>> assuming good intentions. >> >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "geoengineering" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/geoengineering/l5fmgzA34HY/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] >> <mailto:[email protected]>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/geoengineering/4401b957-3be3-4b0c-9982-811847c5b95cn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/geoengineering/4401b957-3be3-4b0c-9982-811847c5b95cn%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAM79iSh1i0rdezp2EZv2bbWtFbZOZa39rRJYK2N4kD6ZEJiLvA%40mail.gmail.com > > <https://groups.google.com/d/msgid/geoengineering/CAM79iSh1i0rdezp2EZv2bbWtFbZOZa39rRJYK2N4kD6ZEJiLvA%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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