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

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

#531

Post by bluGill »

mr__y wrote: post #472
rhinoceraptor wrote: post #429

Earlier quoted context omitted.

Swapping an EV battery is like swapping an ICE transmission. You can do it if you have a car lift and a scissor jack to drop it.

Sure, but one can argue that a EV could be designed/optimized for faster battery replacement. While it would still need at least a forklift to move the batteries, I believe the time needed for battery swapping could be greatly reduced with a proper design.

Tesla did that for a while. They abandoned the plan. Batteries are big and heavy. It turns out to be far more important that engineers have the ability to fit them around the other parts (suspension...) than the ability to swap a standard battery.

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

#532

Post by po »

phonebucket wrote: post #510

What happens with the gasoline after it’s made? Does it get burnt again? I’m guessing the energy released from burning that gasoline must necessarily be less than the energy used in creating it. Then the net is going back to square one with regards to CO2, but with a net loss of renewable energy? I may well be off the mark here, so would appreciate it if someone could tell me what I’m missing.

I think the idea is that you're powering traditional combustion engines with a fuel generated with green power. It may be more wasteful of that green electricity than a new EV charging from the grid would be but you didn't have to build and buy a new thing and it's kind of fine to waste renewable energy if the economics works out because it's renewable.

So it's effectively a way to convert your ICE car into a zero-emission EV by using that fuel.

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

#533

Post by simonh »

brilee wrote: post #428

A few questions from a chemistry major 1. why extract from the air when you can just put a device on the smokestack of an existing coal or natural gas plant? The higher CO2 density of the effluent will make things more efficient. 2. Your key innovation isn't the part where you pull CO2 out of the air; it's the nanotube-based reverse osmosis process for separating ethanol from water. This process could just as easily…

> why extract from the air when you can just put a device on the smokestack of an existing coal or natural gas plant?

So you have spare available energy you can use to run the converter, and you also have a demand for energy that you're satisfying using a hydrocarbon powered generator. Why not reduce your hydrocarbon use in the first place, by substituting in the energy you were going to use in the converter? That seems to me to be an awful lot more efficient.

IMHO this technology really comes into it's own when you have available spare renewable energy, and want to find a way to store it in a dense, portable and easily reusable form. I think it's best thought of as a competitor to battery storage, but with the added benefit of extracting atmospheric CO2.

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

#534

Post by rmcginnis »

frantzen wrote: post #530

Hello Rob, thanks for the post! Has your company performed an energy return on energy invested (EROI) accounting for your process? Few companies if any provide a comprehensive EROI and/or CO2 emissions accounting for their product(s). I know you explained that the inputs are low-carbon; however (1) “renewable” energy is still anywhere from 10-50 gram CO2 per kWh (effectively), and (2) the CO2 intensity of your capita…

Thanks! We haven't done a unique analysis yet, but here is a paper that does a good overview of energy balances and efficiencies for CO2 to fuels and products. In their separations discussion you can see why distillation of alcohols is not favorable. A membrane approach is approx. 6x better, but until the CNT membrane was shown to do this job, there was no practical way to do the separation at this efficiency.

https://www.cell.com/joule/fulltext/S2542-4351(18)30042-4

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

#535

Post by zaroth »

bluGill wrote: post #527
kbutler wrote: post #349

Earlier quoted context omitted.

Interesting stats on the battery replacement, but if my family/youth groups/etc. routinely took 20+ minutes for a gas station bio break, there'd be words. Especially if we had to do it every 150 miles (80-15%).

I go both ways on that one. On the one hand I want to get there. On the other hand my doctor wants me to get out and take a 10 minute walk every hour anyway.

Also worth mentioning that 65% of the LR Model 3 is over 200 miles.

So if you are starting the day with 95% charge, and ending the day plugged in at your destination with 15% charge, that means you can travel about 450 miles with just one ~20 minute stop to charge along the way.

How is that not fast enough? The only issue is if you can't plug in at your destination. Maybe in that case you have breakfast near the next Supercharge on your route.

Yes, it is something you might have to think about for a minute. The guidance software will map out Supercharging stops for you.

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

#536

Post by rhinoceraptor »

mr__y wrote: post #472
rhinoceraptor wrote: post #429

Earlier quoted context omitted.

Swapping an EV battery is like swapping an ICE transmission. You can do it if you have a car lift and a scissor jack to drop it.

Sure, but one can argue that a EV could be designed/optimized for faster battery replacement. While it would still need at least a forklift to move the batteries, I believe the time needed for battery swapping could be greatly reduced with a proper design.

I’d much rather have an EV optimized for efficiency, battery endurance, etc. given that battery swaps would only really be useful for long distance road trips.

But you’d still need to have expensive batteries in stock on location, technicians and equipment. I can’t see that ever being done at scale.

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

#538

Post by ossie »

simonh wrote: post #522
ossie wrote: post #516

Earlier quoted context omitted.

That is not what I was suggesting.

You said: >Imagine power plant stack exhausts channeled through this technology What's I'm saying is, if you have spare energy available to power the converter, you're better off reducing the hydrocarbon power plant output and replacing that output with your 'spare' energy supply. Doing so would be dramatically more efficient. The only case this doesn't apply is if there is no way to substitute your spare available e…

Ok, I understand where you're coming from, and its a logical argument. However, a lot of fossil generators (esp coal) are baseload plants that stay running for system reliability. They might stay running during off-peak hours when the output is barely needed, just to ensure availability during on-peak hours. In those cases, you can't tweak output to match variable renewable energy output.

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

#539

Post by rhinoceraptor »

bluGill wrote: post #531
mr__y wrote: post #472

Earlier quoted context omitted.

Sure, but one can argue that a EV could be designed/optimized for faster battery replacement. While it would still need at least a forklift to move the batteries, I believe the time needed for battery swapping could be greatly reduced with a proper design.

Tesla did that for a while. They abandoned the plan. Batteries are big and heavy. It turns out to be far more important that engineers have the ability to fit them around the other parts (suspension...) than the ability to swap a standard battery.

Yep, the batteries are ridiculously heavy and they’re used as structural elements in the car.

So swapping batteries is hard to do, and unnecessary for most drives. Sure, you’d want to be able to swap batteries in five minutes like pumping gas. But who’s going to ship batteries out to the middle of Kansas, build infrastructure, and pay technicians just for people on a road trip who want to swap batteries?

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

#540

Post by frantzen »

Hello Rob, thanks for the post! Has your company performed an energy return on energy invested (EROI) accounting for your process? Few companies provide comprehensive and transparent EROI and/or CO2 emissions accounting for their product(s). I know you explained that the inputs are low-carbon; however (1) “renewable” energy is still anywhere from 10-50 gram CO2 per kWh (effectively), and (2) the CO2-intensity of your capital equipment can be depreciated over the useful lifespan of said equipment and allocated to each effective unit of energy generated (kWh or gallon?). I’m genuinely excited about your technology; your low capital costs, inexpensive materials, flexible/intermittent operations, and hopefully low maintenance cost — all sound very promising.
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