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 On Thu, Dec 29, 2022 at 6:07 PM Russell Seitz <[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] > 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]. > 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. 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