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Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

news.ycombinator.com

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Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#211

Post by mrep »

34k5jo3i4toig wrote: post #109
tathougies wrote: post #85

Earlier quoted context omitted.

Can you elaborate how gasoline is 'dirty' if the outputs were converted back into the fuel via carbon neutral means? Such technology would make gasoline have no output, since the ouptuts would be reabsorbed. If anything, electric cars, due to the massive environmental damage due to rare earth mineral mining, would be more of an environmental disaster.

Every cycle has a 50% cost in renewable power. This is close to being carbon neutral, but it is not entirely. Its not a closed loop. You have a growing loss every cycle. Its digging yourself deeper every time.

Well of course it's not 100% energy efficient. Nothing we do is 100% efficient because we cannot escape the second law of thermodynamics (entropy).

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#212

Post by Robotbeat »

semi-extrinsic wrote: post #73
mrguyorama wrote: post #28

Would you be willing to share vague details of your roadmap? Specifically; How many barrels of ready to burn gasoline are you outputting per day in 6 months? 1 year? 3 years? The fact that the general fuel is going to be sold and re-burned means this is at best carbon neutral, so from a cynical environmentalist point of view, what's the point? This can't help anyone unless you pump the synth-gas into the ground and s…

The main thing that's turned me positive on "e-fuels" is that there's such a huge amount of petroleum that's used today in applications where we basically have no other options . Think stuff like big jets, or container ships. If you sit down and crunch the numbers for any non-carbon energy carrier, you either end up sinking the ship or with a fuel tank twice the size of the cargo.

The problem with e-fuels for jets is that a majority of the climate forcing comes from the high altitude water vapor in the exhaust, not actually the CO2. EDIT: I should point out here you COULD actually make an e-fuel without hydrogen and thus without water vapor as a combustion product. Carbon monoxide, for instance. The energy density is much lower, but it is sufficient. HOWEVER, there are obvious safety concerns with CO fuel that basically makes that a non-starter. Another option is a fuel cell that condenses the water output and stores it for periodic (possibly lower altitude) discharge in liquid form.

But I agree container ships would be a good application of this. Container ships also have pretty high efficiency internal combustion engines (about 50%), meaning there's less advantage in electrification there than for land vehicles which often have 15-25% efficient engines. And it allows low particulates, which is one of the main forcing regulations on shipping powertrains nowadays, without the overhead of cryogenic LNG.

However, container ships use ridiculously cheap bunker fuel instead of highly refined gasoline.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#213

Post by ncallaway »

perfunctory wrote: post #190

> If the cost of our equipment is also low, then we believe we can not only make zero carbon fuel, but actually compete on price with fossil fuel. even if it can compete with fossil fuel, do you think it will also be competitive with BEV?

Fuels are used in lots of places besides cars where batteries aren't necessarily viable options.

Large transport ships, airplanes, and rockets all are a long way of from being able to be electric.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#214

Post by beat »

jvanderbot wrote: post #121

So, the goal is carbon-neutral gasoline. Short term, I suppose your target is feel-good gas burning vehicles. Longer term, do you envision this technology being used for clean(er) + carbon neutral municipal power generation, or is the fuel type just wrong for that? I ask because a stop-gap can easily become permanent, and it'd be unfortunate to continue dumping particulates (pm2.5/10), smog, etc into the air in major…

The perfect is the enemy of the good.

We have a carbon problem now, that is causing real damage now. We shouldn't be turning our noses up at "stopgap" just because it doesn't do everything we can dream of doing.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#216

Post by kresmoi »

Does your 60kWh/gallon gasoline quote include the energy needed for airflow to hit the production scale you expect? This is a significant cost and is why https://www.nature.com/articles/s41467-019-09685-x#ref-CR33 proposes integration with A/C systems.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#217

Post by rmcginnis »

ineedasername wrote: post #144

So if this is basically eliminating the traditional "distillation" phase by using the membrane, do you envision a day when I can dip your membrane in my beer and then poor off some moon shine?

Yes, you could do that now!

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#219

Post by rmcginnis »

lutorm wrote: post #200

This is a cool project! One question though: why is getting rid of thermal processes an improvement? If you're getting electricity from solar, you can get even more thermal energy from solar since the conversion efficiency for capturing heat is much higher.

The cost of solar and wind electricity is low and getting lower. SImilar investments have not been made in renewable heat (like geothermal or solar heat), so they are not as inexpensive. Also, a thermal process needs to run continuously (24/7 if possible), whereas a pure electric process can run intermittently, which is a better fit for the zero carbon energy resources.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#220

Post by progval »

My most immediate question (after others you already answered in this thread) is about getting enough CO2.

When you start absorbing CO2 from the air, won't the CO2 in the neighborhood be depleted very quickly? And I'm assuming you can't pump enormous amounts of air either for various reasons (noise, energy usage, other environmental issues). Of course there's wind to bring more CO2, but I'm curious about your computations.

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