A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19) • Hacker News Board

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#111

Post by Hasz » Wed, May 01, 2019, 3:20 AM UTC

rmcginnis wrote: post #98

Hasz wrote: post #12

Soooooo many questions. Gasoline is a distillate made up of several hydrocarbons -- is he synthesizing all of them, or just octane? What about additives, like anti-knock agents? Plans for diesel? No amount of fancy CNTs gets around thermodynamics. CO2 and H20 are far more stable, thermodynamically, than octane, it's partially why octane is a good fuel. Where does the extra energy come from? What is the efficiency of…

Hi, this is Rob, founder of Prometheus. The conversion of CO2 and water to gasoline is not a super efficient process, likely 50-60% at best in the near term, but that's ok, if the electricity is from a zero carbon source like solar or wind, and the cost of the electricity is low (which these days it is). The CNT membranes are being made at full commercial scale now by my previous startup, Mattershift. Ready to go! We…

Hey, thanks, and best of luck, what a cool company.

It seems like you're on the cusp of breaking even from yongjik's back of the envelope math, at least for the US commercial market. Is this a refinement of Fischer-Tropsch?

However, I think you're barking up the wrong tree. The US military pays $hundreds of dollars to get fuel into a warzone. If you can make diesel (which I think you can), you don't have to go after a $3 a gallon target, you go after a $300 target. You can perfect it on sweet sweet DARPA money at a price point that will make you rich and save the military a shitload of money.

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#112

Post by yongjik » Wed, May 01, 2019, 3:22 AM UTC

ajross wrote: post #105

yongjik wrote: post #103

OK, I was curious so just did some math. Gasoline has energy density of 34.2 MJ/L, or 9.5 kWh/L[1]. Its retail price is about $3/gallon, or $0.8/L. So, assuming 100% efficiency, the energy source for making gasoline should be ~$0.084/kWh to break even. Energy Information Administration (EIA) estimates 2022's solar/wind generation cost at $73.7 and $55.8 per MWh [2], or $0.0737 and $0.0558 per kWh. Assuming wind power…

If there were realistic competitors for fossil fuels, we wouldn't be worrying about a climate crisis in the first place. Nothing is going to compete with pumping fuel out of the ground, and it never will. Any realistic scenario starts with some kind of regulation on carbon extraction and then worries about the economics of replacements. And technologies like this one that claim to be within a factor of two seem very…

But all these renewable energy sources are already competing with fossil fuels and sometimes even winning! And even with these sources you can't make synthetic gasoline economically viable.

That leads to the question: if one can sell synthetic gasoline at profit, they must have a really cheap source of energy, in which case why go through the trouble of gasoline instead of selling the energy directly?

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#113

Post by solotronics » Wed, May 01, 2019, 3:26 AM UTC

rmcginnis wrote: post #92

MuffinFlavored wrote: post #9

Earlier quoted context omitted.

How much do today's "carbon recapture" methods need to grow? What's the timeline on them looking like? P.S. The first Google result for carbon recapture is titled "“Direct air capture” of carbon dioxide won't solve climate change" P.P.S From Wikipedia with a cited source: capturing and compressing CO2 and other system costs are estimated to increase the cost per watt-hour energy produced by 21–91% for fossil fuel pow…

Hi, Rob from Prometheus here! Most of the skepticism about CO2 removal from the air is focused on "carbon sequestration and storage" or CSS, which is mitigation of emissions from fossil fuel by putting CO2 into the ground, for example. Turning CO2 from the air into useful products like fuels and building materials is much more capable of scaling because these products have value independently from regulations or carb…

very exciting! Do we know yet if gasoline is the most efficient hydrocarbon to make from CO2 for a given amount of electricity? I would think there are a whole range of oil like things that could be produced. I always dreamed about using nuclear power to do all kinds of terraforming type things that would otherwise be energy inefficient.

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#114

Post by blurbleblurble » Wed, May 01, 2019, 3:29 AM UTC

ajross wrote: post #106

blurbleblurble wrote: post #102

The carbon costs of manufacturing a replacement fleet of cars is surely vast. Meanwhile, the internal combustion engine is perfectly capable of running on a whole slew of renewable fuels, including but not limited to hydrogen gas, methanol, etc. It's not the most efficient in the long run, but it's a piece of the puzzle, especially when you consider the baseline energetic/carbon costs of building new vehicles from sc…

The point about the desirability of a direct liquid fuel replacement for transportation is valid, but this logic doesn't work: > The carbon costs of manufacturing a replacement fleet of cars is surely vast. Cars have finite lifetimes. You don't replace the ones on the road, you replace the ones we'll buy in the future. And this one... well... > P.s. lithium is a conflict mineral now citation REALLY needed

> Cars have finite lifetimes. You don't replace the ones on the road, you replace the ones we'll buy in the future.

Apologies... I realize upon rereading what I wrote that it was all a little hyperbolic.

My point is that renewable hydrocarbon fuels could extend the use of already manufactured cars in a way that saves energy on the supply end, much in the same way that thrift stores extend the lives of worn clothing and satisfy a lot of demand that might otherwise go toward pressuring suppliers to make new clothes. It pays, energetically, to reuse and recycle (two out of the three R's right there!) Renewable hydrocarbon fuels would effectively "recycle" existing cars. I don't have any hard numbers but my hunch is that economically this could be quite a significant effect.

Combined with hybrid conversion kits, renewable hydrocarbon fuels could make existing vehicles into a viable piece of the sustainable transportation puzzle.

> citation REALLY needed

http://gppreview.com/2018/02/07/motivations-unearthed-re-con...

https://www.globalresearch.ca/more-american-troops-to-afghan...

http://www.futuredirections.org.au/publication/the-united-st...

https://www.nytimes.com/2010/06/14/world/asia/14minerals.htm...

From the mouth of the beast itself: https://www.voanews.com/a/afghanistan-trump-mining-lithium/3...

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#115

Post by fallingfrog » Wed, May 01, 2019, 3:30 AM UTC

rmcginnis wrote: post #92

MuffinFlavored wrote: post #9

Earlier quoted context omitted.

How much do today's "carbon recapture" methods need to grow? What's the timeline on them looking like? P.S. The first Google result for carbon recapture is titled "“Direct air capture” of carbon dioxide won't solve climate change" P.P.S From Wikipedia with a cited source: capturing and compressing CO2 and other system costs are estimated to increase the cost per watt-hour energy produced by 21–91% for fossil fuel pow…

Hi, Rob from Prometheus here! Most of the skepticism about CO2 removal from the air is focused on "carbon sequestration and storage" or CSS, which is mitigation of emissions from fossil fuel by putting CO2 into the ground, for example. Turning CO2 from the air into useful products like fuels and building materials is much more capable of scaling because these products have value independently from regulations or carb…

It’s not thermodynamically possible to recapture carbon from the air without using more energy than was obtained by burning it the first place.

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#116

Post by fallingfrog » Wed, May 01, 2019, 3:32 AM UTC

rayiner wrote: post #5

This is really, fundamentally important technology. Emissions reduction will not work: https://www.scientificamerican.com/article/nations-are-not-r... > The authors of the report stated in a press release that the kind of drastic, large-scale action the planet desperately needs has yet to be seen, even though global emissions have reached record levels at 53.5 billion metric tons in 2017, with no signs of peaking. >…

It’s not thermodynamically possible to recapture carbon from the air without using more energy than was obtained by burning it in the first place.

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#117

Post by fallingfrog » Wed, May 01, 2019, 3:35 AM UTC

rmcginnis wrote: post #96

PaulAJ wrote: post #87

Earlier quoted context omitted.

"Unburning" CO2 takes energy. Where does your energy come from?

We use zero carbon solar and wind electricity. As long as the electricity source is zero carbon and low cost, it makes economic and practical sense to make zero carbon fuel.

Ok but why not just use the zero carbon electricity, if you have so much of it?

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#118

Post by fallingfrog » Wed, May 01, 2019, 3:41 AM UTC

peteretep wrote: post #51

natch wrote: post #44

Earlier quoted context omitted.

>I strongly suspect that manufacturing hydrocarbon fuel out of air, water, and electricity If you already have electricity, that is all the energy you need. There is no need to use it to produce a toxic, polluting fuel that is used in highly inefficient internal combustion engines. Simply use electric motors, which are way more efficient.

> If you already have electricity, that is all the energy you need If you can store and transport it better than gasoline can be stored and transported, which ... so far you can’t.

Why not just build electric trains?

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#119

Post by zamfi » Wed, May 01, 2019, 3:45 AM UTC

fallingfrog wrote: post #117

rmcginnis wrote: post #96

Earlier quoted context omitted.

We use zero carbon solar and wind electricity. As long as the electricity source is zero carbon and low cost, it makes economic and practical sense to make zero carbon fuel.

Ok but why not just use the zero carbon electricity, if you have so much of it?

They're going after the use case of gasoline as energy storage, not gasoline as primary energy production.

The reason, today, that cars are powered by gasoline and not electricity is not the cost of the energy itself, but the cost of storing it.

Obviously it would be better to use the electricity directly. But it's hard to get that electricity to a moving car on the road (or a plane in the sky).

Re: A Quest to Make Gasoline Out of Thin Air: Prometheus (YC W19)

#120

Post by fallingfrog » Wed, May 01, 2019, 3:52 AM UTC

zamfi wrote: post #119

fallingfrog wrote: post #117

Earlier quoted context omitted.

Ok but why not just use the zero carbon electricity, if you have so much of it?

They're going after the use case of gasoline as energy storage, not gasoline as primary energy production. The reason, today, that cars are powered by gasoline and not electricity is not the cost of the energy itself, but the cost of storing it. Obviously it would be better to use the electricity directly. But it's hard to get that electricity to a moving car on the road (or a plane in the sky).

It’s not that hard. You can just charge the car inductively with wires in the road, or better yet, just lay tracks for electric trains.