On the side note, anybody knows what happened to the prometheus startup [0]? Are they still alive?
Engineers are developing new ways to convert greenhouse gases to fuel
91–100 of 213 posts
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#92The actual title is "UC reactor makes Martian fuel" and the subtitle is "A gas station on Mars? Engineers envision the possibilities." But the submission title is "UC reactor converts carbon dioxide to fuel to address climate change"? While it does talk about applications with respect to carbon capture, if we consume the fuel byproduct, presumably we just end up with co2 in the atmosphere? > “In the future we’ll deve…
if we consume the fuel byproduct, presumably we just end up with co2 in the atmosphere?
It's necessary to compare the two things:
1 - we drill out more fossil fuels and burn it
2 - we convert atmospheric CO2 to fuels and burn it
#2 is theoretically infinite and CO2 levels never increase. #1 is very finite and the longer we do it the higher CO2 levels increase.
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#93Earlier quoted context omitted.
The new scrubber sounds like it's not using the old zeolite bed system but one based on molecular sieves. But you're otherwise right that they're not really turning that CO2 into anything on the regular beyond the limited ISRU experiment(s).
Zeolite is a molecular sieve. That's just a fancy word for "material that selectively holds on to some types of gasses" (CO2 and H2O in the case of zeolite). I haven't followed the new bed system though, I'd be very interested to know if it was using a different molecular sieve (and somewhat surprised if they are).
Ah yeah reading a bit closer further down they mention it's a 4 bed system and this is largely an iterative improvement instead of a new system entirely.
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#94Earlier quoted context omitted.
This is an important point. Not for the "we'll build a gas station on mars"-scenario, but for the "we'll propose this as a climate solution". Every way of replacing natural gas with some other source of methane - be it the sabatier process or biogas/biomethane - has this problem. It can only be a climate solution if you can bring leaks down close to zero, which is very challenging. It also makes one wonder whether e-…
Methane is produced naturally in vast quantities by decaying organic matter, cow farts, released from volcanoes, natural reservoirs, etc. I doubt that some small leaks in an industrial process would make a real difference. It would probably be undetectable in comparison to the leaks in our current natural gas infrastructure that we use for heating homes, cooking, and electrical generation.
This may very well be the case that it's a non-issue, but an article that only mentions the good parts without even acknowledging potential problems with the solution makes me think "what else did they not mention that a lay-person like me wouldn't know about?".
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#95It's been seemingly impossible to motivate the world to switch to alternatives to fuel. We're between a rock and a hard place with society and the environment. It seems like there isn't even a conspiracy, it's just a combination of poor choices, greed, and new technology. Solar is great, but often it's more expensive than just consuming grid power or has unpredictable payoffs. Wind has a lot of upfront costs. Massive…
> It's been seemingly impossible to motivate the world to switch to alternatives to fuel. The impossible part is we have yet to discover a density/cost comparison to hydrocarbons. No one is going to “switch” to something that isn’t as good as the existing option. Couple this with “but electric cars!” that often are still just coal powered. Plastics, military, actual logistics, China, we’re going to burn every drop of…
If you're taking what I said to mean "of course individuals should just do better," I definitely didn't mean to imply that. Exactly the opposite, actually.
It's a bunch of smaller decisions that are hampered by new technology and lack of economies of scale, among many other compounding factors that result in poor consumer/business/utility/government choices (for the environment). I think sequestering may be an important part of that, but it's still new technology.
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#96I wish they addressed the fact that methane that they will be producing is said to be an even more potent greenhouse gas than carbon dioxide. Are there any worries about the leakage for example?
Starting a greenhouse effect on Mars would help it become more livable by humans.
Part of the article speaks about the uses that are a bit closer to home. I'm not that worried about Mars, that part is still SciFi to me and I probably won't live long enough to see it become reality. :-(
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#97It's a clickbait title, like the "fuel from water" people and the "hydrogen economy" people. Yes, with enough energy you can crack hydrocarbons out of combustion products. This is only useful if you have plenty of energy but it's not in a portable form suitable for rockets. As a means of removing CO2 from Earth's atmosphere, it's hugely inefficient. If you have that much electricity around, use the electricity, don't make hydrocarbons so you can burn them again.
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#98For Mars? What would carbon-based fuel on Mars be burned with? There's not much O2 there!
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#99Don't get your hopes too high if you think this can be used to scrub significant amount of CO2 from atmosphere.
Don't get me wrong, producing fuel from atmospheric CO2 is still wonderful news.
But you know what they produce? Methane. And methane is what? It is A FUEL. And what we do with fuel? We BURN it. Once you burn methane you get the CO2 back, for net ZERO effect on the atmosphere.
The only way this works to help the climate is if you can use thus produced methane to remove need for mining actual gas. Unfortunately (or fortunately), we are already on the way to reduce a lot of mining for energy by replacing it with electricity. So according to Amdahal's law, the benefit is also going to be small.
Producing and burying methane clathrate is still impractical and would be very risky, because they can get resurfaced and then methane is hundreds of times more potent as warming agent than CO2.
Re: Engineers are developing new ways to convert greenhouse gases to fuel
#100Earlier quoted context omitted.
If they’re not recycling CO2 into O2 and instead venting CO2 to space, does that mean ISS is constantly losing gas and it needs an ongoing resupply of oxygen all the time? I thought oxygen was used fast enough to make resupply impractical, but perhaps there are in fact gigantic tanks of O2 under immense pressure somewhere aboard the ISS.
Yes, and sort of. The ISS is constantly losing gas, I believe that the primary source of new O2 is actually electrolysis of water, not pressurized tanks, but that they do also have pressurized tanks as a backup. A person breathes out roughly 1kg of CO2/day, and it follows you breathe in about the same amount of O2, not an impossible amount of mass to resupply.
And, to complete the equation: that carbon comes up in the form of food.