Dude, where's my fuel? • Hacker News Board

Re: Dude, where's my fuel?

#151

Post by scotty79 » Thu, May 05, 2022, 1:47 PM UTC

archi42 wrote: post #136

chrischen wrote: post #68

How does this compare (in terms of efficiency and energy loss) to just using the electricity directly in a battery electric vehicle?

They say they need 77kWh to produce one gallon of fuel. Which has 33.7kWh of energy stored. Assuming 20% average efficiency of an ICE engine (from Wikipedia), so 6.74 kWh per gallon end up as actual "work" done by the engine. A quick DDG search suggests BEV has an efficiency of 80%, so the same 77kWh would end up doing 61.6 kWh of actual work when charged directly. IMHO long-term this is no solution for general trans…

This has the benefit of creating incentive for capturing CO2 which is something we should be willing to pay for in coming decades.

Re: Dude, where's my fuel?

#152

Post by scotty79 » Thu, May 05, 2022, 1:50 PM UTC

Layke1123 wrote: post #46

I see carbon nanotube tech and become immensely skeptical. I am under the impression that anything carbon nanotube still cannot be done at scale, and the article is very light on that part of the process. Following the rabbit hole leads to http links (in 2022?) and various publications from science journals I am unfamiliar with. Does anyone else get the smoke and mirrors vibe from this or am I just being overly skept…

It's not a key element of their process. You could just distill it and humanity had millenia of expeirience in scaling and optimising that process.

Re: Dude, where's my fuel?

#153

Post by molyss » Thu, May 05, 2022, 1:54 PM UTC

Folcon wrote: post #114

Osiris30 wrote: post #73

Earlier quoted context omitted.

Relevant thread - question asked by Ramez Naam on the feasibility of Prometheus: https://twitter.com/ramez/status/1516199169911713794?s=21&t=...

> Bluntly? They are a running joke among anybody that has been around the renewable fuels space for longer than a couple years. > There are no shortcuts around the physics required to assemble a molecule. So the process is viable, but the cost is prohibitive?

I just don’t understand the answer. Seems to be conflating “energy cost” and “financial cost” under the same umbrella. I don’t think Prometheus is disputing the energy costs of “the physics required to assemble a molecule”.

Current processes use heat+pressure, which are pretty wasteful, and often rely on burning fossil fuels in the 1st place, which will mechanically increase the financial cost”

What I understand from Prometheus is that they have a different way to “assemble molecules”, which relies on “electrocatalysts” instead of “catalysts requiring high temperature and pressure”. On the face of it, I can totally see how such a catalyst would decrease the “financial cost” without necessarily impacting the “energy cost”. It’s simply using a cheaper energy than the current processes.

The twitter answer rings similar to someone who would say “There is no shortcuts around the physics of producing light” to justify why LED lightbulbs would never make it. Most of the energy of incandescent bulbs is just heat, and there are physical process that produce light without all that heat. I don’t see any reasons why the extra heat would be needed to produce fuels

Re: Dude, where's my fuel?

#154

Post by seltzered_ » Thu, May 05, 2022, 1:54 PM UTC

alex_young wrote: post #69

ncmncm wrote: post #63

Earlier quoted context omitted.

Tractor fuel produced at the foot of a wind turbine in the middle of a farmer's field, that doesn't need to be transported from a refinery, would have immediate value. Fences made of double-sided solar panels mounted a bit more than tractor-width apart, running N-S, coexist nicely with row crops, and cut water loss, improve conversion efficiency (via evaporative cooling), and often increase yield besides (via reduced…

Why not just make electric tractors? The energy efficiency of converting wind -> electricity -> fuel -> mechanical power has to be less efficient than wind -> electricity -> mechanical power right?

You have to look at gravimetric and volumetric energy density, the book 'the future is rural' has a nice chart on this:

https://twitter.com/vivekgani/status/1426017955398176770?t=0...

Re: Dude, where's my fuel?

#155

Post by 6510 » Thu, May 05, 2022, 1:55 PM UTC

beachy wrote: post #25

neonate wrote: post #14

[Since a lot of people can't read the article and the format is annoying enough that even archive services haven't captured it, here's the text.] As you know, Prometheus converts renewable electricity from solar and wind power into zero net carbon gasoline, diesel, and jet e-fuels (short for “electro-fuels”) that compete with fossil fuels on price. What some readers may not know is that the process we use to do this…

I don't think I've ever seen a web site where the content was so interesting, but the presentation was so piss poor that the bulk of visitors likely leave without having even read any of this cool stuff. For the love of god, throw your web site away and start again with some simple, static HTML pages.

The page we are reading can quite easily be remade into a normal web page as it involves few of the exotic/mind blowing animations seen elsewhere on the website.

The first page view shouldn't be loading all that crap that isn't being used.

Re: Dude, where's my fuel?

#156

Post by archi42 » Thu, May 05, 2022, 2:09 PM UTC

scotty79 wrote: post #151

archi42 wrote: post #136

Earlier quoted context omitted.

They say they need 77kWh to produce one gallon of fuel. Which has 33.7kWh of energy stored. Assuming 20% average efficiency of an ICE engine (from Wikipedia), so 6.74 kWh per gallon end up as actual "work" done by the engine. A quick DDG search suggests BEV has an efficiency of 80%, so the same 77kWh would end up doing 61.6 kWh of actual work when charged directly. IMHO long-term this is no solution for general trans…

This has the benefit of creating incentive for capturing CO2 which is something we should be willing to pay for in coming decades.

That's a distraction: The extraction is only temporarily. The value of an amount of efuel is not in that it's made from captured CO2, it's in burning that efuel to drive some machine. So yeah, there will be some CO2 captured in storage and transit, but that's will be less than what we release every year.

If you want to capture CO2 for good: Capture it, dump it somewhere and don't touch it ever again. The trick is to derive (monetary) value from the permanent storage. Just digging a hole and dumping it there doesn't make anyone richer (only healthier, but who's paying for that on the necessary scale?). Thinking about it, maybe we can use it in construction?

Re: Dude, where's my fuel?

#157

Post by thinkcontext » Thu, May 05, 2022, 2:40 PM UTC

no_wizard wrote: post #33

This all sounds amazing but it also gives me Theranos vibes. While I understand the general science around this has been around a long time (the aforementioned Fischer Tropsch process) I would love for this to get some independent scientific validation before I'm willing to buy in to their dream here. It just "feels" too good to be true. Even with the Faraday Reactor considerations Seems much more scientifically plau…

You aren't the only one. This recent article captured a lot of skepticism from people in the field. And then there's history of optomistic predictions, in 2018 McGinnis predicted they'd be undercutting gasoline in 2019.

https://www.technologyreview.com/2022/04/25/1050899/promethe...

Re: Dude, where's my fuel?

#158

Post by leobg » Thu, May 05, 2022, 2:45 PM UTC

DennisP wrote: post #142

leobg wrote: post #111

Earlier quoted context omitted.

If I read just one book of this author, which should I read? Or if not a book, which podcast/video? Thank you.

Geopop videos on youtube were my introduction, and are definitely the quickest way to get the gist. Then I started reading his books. Accidental Superpower is his first, from 2014, and is the best overall introduction. It doesn't just look at current events; he applies his approach to pretty much all the great civilizations of world history, starting with ancient Egypt. Well worth reading for that alone, it's amazing…

Thank you. Very helpful. Reading it now!

Re: Dude, where's my fuel?

#159

Post by thinkcontext » Thu, May 05, 2022, 2:48 PM UTC

This posting seems to be a response to a bunch of skepticism about them that has surfaced recently. MIT Technology Review published an article about them that contained several critical perspectives, including:

> “It’s laughable,” says Eric McFarland, a professor of chemical engineering at the University of California, Santa Barbara. “It’s the tech bubble again,” he added later. “People are putting money into lots of things that ultimately won’t ever work, and this is one of them.”

And it points out that the CEO (and submitter here) has a history of making predictions that have not come true, such as saying in 2018 that they would be able to undercut gasoline on price in 2019.

I really hope they are able to do what they say they can do but I won't be at all surprised if they fail.

https://www.technologyreview.com/2022/04/25/1050899/promethe...

Re: Dude, where's my fuel?

#160

Post by ncmncm » Thu, May 05, 2022, 3:12 PM UTC

jabl wrote: post #127

coderenegade wrote: post #108

Earlier quoted context omitted.

Maybe. Ammonia is certainly the best carbon-free fuel, the only real issue with it is its toxicity. Methanol is a lot easier to handle since it's a liquid at SSL conditions, and generally less dangerous, but it has it's own downsides (it's hygroscopic, for example). But I agree with you in the sense that, to me at least, the two most sane options for an e-fuel are methanol and ammonia. I think the path of trying to m…

> Ammonia is certainly the best carbon-free fuel, the only real issue with it is its toxicity If we don't care about toxicity, might as well go with hydrazine, which is liquid at room temperature and has higher energy density than ammonia. ;) (No idea about the cost of hydrazine synthesis, though) > most sane options for an e-fuel are methanol and ammonia The article seems to say their process produces ethanol. If it…

We do, in fact, care about toxicity, so do not e.g. expect to see ammonia powering cars.

NASA and ESA are phasing out use of hydrazine because of its unfortunate handling characteristics. But solid hydrazone might still find uses.

Among the chief attractions of ammonia is that it is very simply synthesized with free feedstock. You bond hydrogen stripped from water to nitrogen from air. Although toxic, it is a lot lighter than air, so if it leaks it goes up, and does not hang about poisoning people in a broadening area.

The main problem with hydrocarbons as synthetic fuel is that you need the carbon, which in air is at below 0.05% concentration. It is certainly possible, but seems unlikely to approach ammonia in cost.