Dan What's your view on using CH4 as a lifting gas at volume scale?
Andrew On Fri, 30 Dec 2022, 16:48 Daniele Visioni, <[email protected]> wrote: > 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 > > > > 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. > To unsubscribe from this group and stop receiving emails from it, send an > email to [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. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/520F9480-1D6F-49B1-B526-BAECEFA51049%40gmail.com > <https://groups.google.com/d/msgid/geoengineering/520F9480-1D6F-49B1-B526-BAECEFA51049%40gmail.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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