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)

#261

Post by aoner » Wed, May 01, 2019, 9:47 PM UTC

icelancer wrote: post #186

ForHackernews wrote: post #60

Earlier quoted context omitted.

It has to be both. If we want to have any hope, we have to dramatically cut emissions AND we also have to invent magic new carbon-scrubbing technology and deploy it at a global scale in the next 30 years or so. https://www.vox.com/2016/10/4/13118594/2-degrees-no-more-fos... > As you can see, in either scenario, global emissions must peak and begin declining immediately. For a medium chance to avoid 1.5 degrees, the w…

>> we have to dramatically cut emissions The "we" in this is primarily China and keeping third-world countries from industrializing using the means that the Western world used to get up to speed. It is not the Western countries, as raynier pointed out. As long as we understand the magnitude - and perhaps incredible unfairness - of the problem, then that's fine. But cutting emissions in the United States and Europe is…

This is such a common misconception. US per capita emissions are around 15 tons and China is around 7 tons. And don't forget that there is a lot of creative accounting going on. All carbon emissions are "exported" by making china the factory of the world. Furthermore flying is not counted in US emissions... I don't think emissions are actually reducing in the US. And let's not forget about the shale "revolution". Oh also: the US has the highest historical emissions. There is an interesting interactive graph made by carbonbrief: https://mobile.twitter.com/carbonbrief/status/11207159885326...

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

#262

Post by aoner » Wed, May 01, 2019, 10:04 PM UTC

An important point that people are missing is that by capturing carbon directly from the air with electricity we can combine two very important energy systems: electrical and chemical. Going 100% renawable at an accelerated pace is within reach and if we could use all excess power due to intermittency to transform the carbon dioxide and synthesised hydrogen into hydrocarbons we can solve some other problems that are currently unsolvable before 2050 (jet fuels, chemical industry).

Also if we've improved this technology so that the costs are reduced (50$ per ton) we can do proper negative emissions in a scalable way without many downsides (can be used in non-arable land, no water consumption with low temperature direct air capture actually has water as a co-product which we can use for electrolysis). We could then sequester the carbon dioxide underground or even create carbonates out of them so we can store them safely in concrete or asphalt in the form of aggregates.

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

#263

Post by cagenut » Wed, May 01, 2019, 10:29 PM UTC

rmcginnis wrote: post #162

cagenut wrote: post #3

that entire article can be reduced to "nanotubes" since its a YC company though maybe we could get the underlying story?

Hi, this is Rob, Founder of Prometheus. There is more info on the podcast that accompanied the print piece here: https://megaphone.link/BLM3585271197 I'm also working on a HN launch summary that will fill in more details.

hi rob, thanks for responding.

unfortunately i sat through that 20 minute podcast and the only thing i learned was $3/gal is your estimate and that the machine has not yet worked. nothing about nanotubes or any attempt at a claim at what the innovation is here.

looking forward to that launch summary

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

#264

Post by jillesvangurp » Wed, May 01, 2019, 10:29 PM UTC

D_Alex wrote: post #176

jillesvangurp wrote: post #154

Earlier quoted context omitted.

Eh no. You are talking about carbon capture as a way to offset fossil fuel consumption. I'm talking about reducing fossil fuel consumption by instead producing non fossil fuels. Apples and oranges. The point of that is not to capture the carbon but to utilize it as fuel. With this technology, that is neither impossible nor prohibitively expensive/unecomincal. Unlike the six schemes you outline that are about not prod…

>The point of that is not to capture the carbon but to utilize it as fuel. >If you are capturing carbon, you might as well do it in a form where you can actually utilize it for fuel. Do you understand that the Prometheus proposes to first capture the carbon and then convert it to fuel? I have no objection to the "convert it to fuel" part. Just to the capture from atmosphere, which is the most inefficient way.

I understand you perfectly. I just don't agree with a single sentence of it. The semantics of carbon capture for you seem to mean to capture some (tiny) percentage of the absolutely epic levels of fossil carbon we put into it today.

The point of Prometeus is to take no fossil carbon whatsoever (0%) and create the fuel directly from the CO2 already in the air and indeed put it back there when it is burned. It's not capturing so much as reusing what is already there. It's by definition the most efficient way. It's 100% efficient.

None of the things you listed actually produce fuel. So they are 0% efficient. At best they offset some meaningless percentage of fossil fuels. Actually raising the cost of those fossil fuels to pay for more meaningful percentages (like more than 1 digit?), just strengthens the business case for Prometheus. The more costly fossil fuel gets, the more attractive Prometheus gets. As it is, they seem to be claiming to be cost effective as is.

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

#265

Post by dredmorbius » Wed, May 01, 2019, 10:35 PM UTC

natch wrote: post #245

dredmorbius wrote: post #182

Earlier quoted context omitted.

They are destroying the environment on which we depend. They are also finite. To further point out the obvious. https://www.ipcc.ch

They are finite but the finite total is over five times the amount needed to utterly destroy the environment... so we need to refrain from using up that finite total.

Whch alone is a sufficient response to your earlier question: https://news.ycombinator.com/item?id=19794993

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

#266

Post by Gibbon1 » Wed, May 01, 2019, 10:38 PM UTC

aaronblohowiak wrote: post #126

Gibbon1 wrote: post #90

Earlier quoted context omitted.

The energy return on energy invested is going to be abysmal. No more than 20% if that. That translates into synth gasoline at $30/gallon

How do you figure?

Estimate the cost of the energy inputs per gallon of gasoline. Account for the inefficiency and you get $15-20/gal.

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

#267

Post by dredmorbius » Thu, May 02, 2019, 4:13 AM UTC

kumarvvr wrote: post #178

Any carbon capture technology, will require infrastructure and components (which release carbon during manufacture), and use energy (no emissions if using renewable fuel). Any analysis ought to take the cumulative total of all the emissions produced during the lifetime of the product vs. the carbon captured. Nature has already given us the most efficient, cheap form of carbon capture. Trees. I hope there will be star…

Moreso than trees: marshes, swamps, and bogs. Wetlands.

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

#268

Post by dredmorbius » Thu, May 02, 2019, 4:16 AM UTC

taneq wrote: post #200

bobthepanda wrote: post #181

Earlier quoted context omitted.

Maybe cars, but the weight of batteries is a problem for larger vehicles that need long range, like a bus, truck, or plane. For those hydrogen might be better.

I think that's backwards. Size and weight of batteries is more of a problem at smaller scales - electric motorcycles get up to around 220 miles (Zero SR) compared with electric cars at 370 miles (Tesla Model S). The Tesla Semi has an advertised range of up to 500 miles.

What's the recharge time for that motorcycle?

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

#269

Post by dredmorbius » Thu, May 02, 2019, 4:27 AM UTC

nordsieck wrote: post #198

bobthepanda wrote: post #181

Earlier quoted context omitted.

Maybe cars, but the weight of batteries is a problem for larger vehicles that need long range, like a bus, truck, or plane. For those hydrogen might be better.

> the weight of batteries is a problem for larger vehicles that need long range, like a bus, truck, or plane. For those hydrogen might be better. China is already leading the world in electric busses. They work great. Busses are such good vehicles for batteries, that for some routes it may even make sense to run them with super-capacitors, with chargers embedded in the road at stops. Trucks are always going to be a p…

For aircraft, fuel characteristics relative to airframe and payload also matters.

Liquid hydrocarbons store readily in wing tanks at temperatures from (roughly) -50C to 50C. Pasengers and cargo can be allocated to fuselage, arranged in a contiguous space for the length of the craft.

Pressurised hydrogen favours cylyndrical or spherical tanks, located near the fore-aft midpoint of the craft, effectively segmenting the (pressurised) fuselage in two; before-pressure-vessel and aft pressure-vessel . Cryogenic hydrogen would require Dewer vessels and venting with considerations for mitigating hydrogen explosion risk -- present over a wide range of concentrations.

And in both cases, metal embrittlement and molecular leakage occur.

Adding a few carbon chains mitigates all these factors.

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

#270

Post by taneq » Thu, May 02, 2019, 6:06 AM UTC

dredmorbius wrote: post #268

taneq wrote: post #200

Earlier quoted context omitted.

I think that's backwards. Size and weight of batteries is more of a problem at smaller scales - electric motorcycles get up to around 220 miles (Zero SR) compared with electric cars at 370 miles (Tesla Model S). The Tesla Semi has an advertised range of up to 500 miles.

What's the recharge time for that motorcycle?

They're a little cagey about that (https://www.zeromotorcycles.com/charging/) but it looks like it can fast charge in ~1hr and charge off a standard wall outlet "overnight".