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Comment by Hasz | Hacker News Reader

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 the conversion? What kind of thoroughput are we talking about?

How scalable - is the CNT manufacturing mature enough to support large scale rollout?

Who is on his team? Research chemists, or experienced chem Es, both hopefully?

I'm sure he knows these answers (man has a PhD is chem), would have loved to sit through that pitch.

The Bloomberg piece is very light on details; the secrecy is frustrating but understandable.

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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've got scientists and engineers from national labs and previous efforts like Project Foghorn at Google. Hope to share some new hires soon.

There was a podcast that was associated with the article, that runs 21 minutes and goes into more details: https://megaphone.link/BLM3585271197

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.

That sounds like a particularly interesting answer, but I wonder what the power and factory requirements would be to have something like this at a FOB or base?

Surely most operating bases use gas powered generators to run and not solar right?

This is genius. Also, the US military can expand everywhere and force everyone to use only the new climate friendly american fuel (TM) for affordable price.

>Where does the extra energy come from?

It doesn't particularly matter. Centralized clean energy production is often significantly easier to solve than figuring out clean alternatives to gasoline use. Especially when the problem with clean alternatives to gasoline is political - it's hard for the US to ban ICE engines in China, but it's significantly easier to sell them carbon-neutral gasoline.

>What is the efficiency of the conversion?

Generally speaking it's pretty atrocious. I don't remember exact numbers the last time I looked into things, but the sense I got is that it's roughly an order of magnitude away from economic viability at current prices.

Also, a significant switch to carbon-neutral fuel would be a significant bump up in electricity and energy consumption. So it's not a cure-all, we'd still need a massive investment in low-carbon energy production.

> It doesn't particularly matter. Centralized clean energy production is often significantly easier to solve than figuring out clean alternatives to gasoline use. Especially when the problem with clean alternatives to gasoline is political - it's hard for the US to ban ICE engines in China, but it's significantly easier to sell them carbon-neutral gasoline.

Oh! Is THIS why we're going about this roundabout process? I couldn't understand why we'd want to spend a lot of effort and energy to inefficiently produce fuel, when we could just produce electricity directly.

Honestly, this comment section is the first place where I've seen this kind of thing discussed logically online.

Using hydrogen fuel cells as an example, everywhere else either 1. Misunderstands thermodynamics, and acts like e.g. producing hydrogen and oxygen from water would somehow result in free energy, or 2. Understands it's energy-negative, but don't explain what the actual benefits would be of storing and using the energy in that manner as opposed to any of the alternatives.

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.

You might find this youtube channel interesting: https://www.youtube.com/channel/UC2rzsm1Qi6N1X-wuOg_p0Ng/vid...

He has run a gasoline engine on a whole slew of fuels, including some that may be surprising, such as isopropyl alcohol, various solvents, crude oil, and a 50% diesel gas mix.

Gasoline engines can also run on pure propane, but the fuel pump, tank, and some other parts do need to be replaced.

I guess the point is that gasoline engines are not in general super sensitive, while they still could be more optimized for certain fuels.

Thats a low compression mower engine. Modern automobile engines are indeed quite sensitive to predetonation from slower ignition times offered by most alternatives without being designed for them.

>Modern automobile engines are indeed quite sensitive to predetonation from slower ignition times offered by most alternatives without being designed for them.

If by "design" you mean a different cam profile to drop the dynamic compression ratio then sure.

Maybe this can be handled by adjusting valve timing in software.

I believe the tuning is controlled electronically through software (this is what enabled VW Dieselgate). So a software update could enable the vast majority of cars to be able to use this fuel.

One thing not considered much on a balance sheet basis, there are a number of different costs. Capital, maintenance, energy, insurance, and taxes/fines/fees.

Battery electric cars exceed or will eventually exceed gasoline/diesel powered cars on a capital, maintence, and energy cost basis.

That sets up a situation where there'll be no market for synth gasoline because the capital and maintenance costs exceeds the energy cost.

Except that will only work for gasoline cars and wont happen for the next 10-15 years. It seems like this guys bet (per the other thread) is that commercial gasoline for cars is the starting point, but they want to move into jet fuel, container ships, and making the basic gasoline/oil that goes into plastics.

Considering there is no commercially available electric passenger aircraft on the horizon (as of now) and that commercial containers are unlikely to convert that seems like a solid market to go after.

And even if you could only replace 95% of the volume of gasoline with renewable-sourced options, is it suddenly a bad idea?

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.

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