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

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

#71

Post by DennisP »

Gibbon1 wrote: post #49
strainer wrote: post #46

Earlier quoted context omitted.

It can be very useful for energy storage and keeping existing combustion plant usable. But the op does not seem to bear in mind the fact that it requires more energy input than it outputs in the form of a carbon neutral fuel, or that renewable technologies have by this date clearly demonstrated affordable solutions to carbon neutral power generation.

When I read about these schemes to produce gasoline from CO2 and water or whatever I can't help but think someone needs a couple of semesters of thermodynamics beat into them.

Nobody thinks they'll get net energy out of this. They're spending energy to make carbon-neutral liquid fuels. The energy would have to come from renewables or nuclear for this to be useful.

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

#72

Post by jsonne »

dflock wrote: post #61

So, you spend a load of energy to reform atmospheric CO2 back into hydrocarbon fuel - and then just burn it again, turning it back into CO2 and putting it back into the atmosphere? The end state of the atmosphere is, at best, the same as the starting state, but you've expended a load more energy for nothing. If the energy to run this process isn't zero-carbon, then this is going to be a big net emitter when done at s…

You don't have to burn it. In theory governments or environmental groups could simple buy and store it.

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

#73

Post by rayiner »

natch wrote: post #37
rayiner wrote: post #16

Earlier quoted context omitted.

The author of the article (who does not appear to be an expert in anything) overlooks that renewables only address part of the emissions picture. Even if the U.S. switched tomorrow to 100% renewables and 100% electric vehicles (including trains, cars, planes, and ships), and you ignore the CO2 emissions of making all those new power plants and vehicles, U.S. usage would only go down by 3.5 gigaton: https://www.epa.go…

>wouldn't offset the growth in India, China, and Africa. And those places are a long ways away from electric cars On the contrary, China is going crazy for electric cars. And the U.S. and EU are starting to turn as well. I wonder where you are getting your ideas.

China put 28 million cars on the road in 2018. 95% were ICE. China put over 1 million heavy trucks on the road in 2018. Almost all were ICE. By 2025, the government aims to get it down to 80% ICE. That’s at least another 100 million new ICE vehicles on the road in the next half decade, plus the 300 million existing vehicles (which in developing nations are retired very slowly). Compared to maybe 20 million EVs if the government meets its target. China is currently building new coal fired capacity equal to the total amount of US coal generation capacity—and many times the renewables capacity it has added in the last year. Power plants are long term investments. These plants will be in service for decades to come.

Again, we need to cut 19 gigatons in the next decade. If “going crazy for electric cars” means that 80% of new cars—forget existing cars, and new trucks, etc.—will still be ICE half a decade from now, emissions reduction is not going to work.

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

#75

Post by gridspy »

m463 wrote: post #67
amluto wrote: post #42

Earlier quoted context omitted.

Or nuclear. A big nuclear plant could be built somewhere with cheap land, no earthquakes, and minimal weather. You don’t even need electric transmission infrastructure. If the capital costs are low enough, cheap or free spot electricity could be used, too. California regularly has excess production.

That would be ironic. We would gradually go from coal and (natural gas) powered electric cars, to nuclear powered ICE cars.

I think the point is that we

1. Keep making more electric cars 2. Rather than throwing away ICE cars, we give them better fuel to use.

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

#76

Post by maxerickson »

rayiner wrote: post #16
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…

The author of the article (who does not appear to be an expert in anything) overlooks that renewables only address part of the emissions picture. Even if the U.S. switched tomorrow to 100% renewables and 100% electric vehicles (including trains, cars, planes, and ships), and you ignore the CO2 emissions of making all those new power plants and vehicles, U.S. usage would only go down by 3.5 gigaton: https://www.epa.go…

How do you switch to 100% renewables and then still have CO2 emissions from heating?

Is the first statement just about transport?

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

#77

Post by joe_the_user »

b_tterc_p wrote: post #29
bifrost wrote: post #8

Earlier quoted context omitted.

At the end of the day - does it matter where it came from? They could be like Tesla and build a solar arm, or a wind farm, or do geothermal. You could pull it out of the grid and it'd still be better for the environment than pulling it out of the ground. TBH saying the world doesn't have a carbon problem contradicts all of the people fighting greenhouse gas emission based climate change so I'm curious as to your logi…

The logic is that you need to power the carbon extraction, and right now we use fossil fuels for power, so you wouldn’t be able to net reduce fossil fuels because you would be burning more than you extract. I think it’s naive though. There is a theoretical point at which it’s economical to just build excess renewable energy production and use the extra power to repair the climate.

The logic is that you need to power the carbon extraction, and right now we use fossil fuels for power, so you wouldn’t be able to net reduce fossil fuels because you would be burning more than you extract.

Currently, we use a mix of hydrocarbon, hydroelectric, photovoltaic, wind and nuclear for power generation. Photovoltaic is quite economical for daylight and so using intermittent power for this process carbon capture process seems reasonable. Broadly, this could serve as a power sink to balance solar output, a way to use renewables for transportation and a way to suck carbon out of the atmosphere. Not all of those at once but just doing some of that seems like a win.

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

#78

Post by [deleted] »

Hasz wrote: post #23
etaioinshrdlu wrote: post #17

Earlier quoted context omitted.

Your car doesn't need a mix of lots of hydrocarbons, it would run fine on pure hexane. Gasoline is a mix because it's made from natural crude which is also a mix... and there's not a strong reason to purify it further.

I imagine the engine is optimized to run on "average" gasoline for a given octane level, tuning compression ratio, spark timing, air mixture, etc. I'm not an ICE engineer, so I would love to know how much of a performance change can be expected from this guy's machine.

[deleted]

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

#79

Post by ineedasername »

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…

I have the same questions. Honestly without answers to at least some these sorts of questions and given his setup sounds like a literal black box, it will be hard not to think "Theranos?" until there are some answers.

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

#80

Post by rayiner »

maxerickson wrote: post #76
rayiner wrote: post #16

Earlier quoted context omitted.

The author of the article (who does not appear to be an expert in anything) overlooks that renewables only address part of the emissions picture. Even if the U.S. switched tomorrow to 100% renewables and 100% electric vehicles (including trains, cars, planes, and ships), and you ignore the CO2 emissions of making all those new power plants and vehicles, U.S. usage would only go down by 3.5 gigaton: https://www.epa.go…

How do you switch to 100% renewables and then still have CO2 emissions from heating? Is the first statement just about transport?

A plurality of home and commercial heating in the US involves direct burning of fossil fuels. So even if the grid is 100% renewables, you’re talking about spending thousands of dollars per house to replace oil and gas furnaces with heat pumps.
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