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)

#231

Post by dwighttk » Wed, May 01, 2019, 12:55 PM 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…

>If they're the only ones running H2, it's probably not going to work.

Aren't they practically the only ones running diesel currently? Maybe Trains + other diesel vehicles is a surprisingly large percentage, but... I'd be surprised.

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

#232

Post by dwighttk » Wed, May 01, 2019, 12:56 PM 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.

>The Tesla Semi has an advertised range of up to 500 miles.

I'll believe it when they ship it.

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

#233

Post by rayiner » Wed, May 01, 2019, 12:58 PM UTC

Mvandenbergh wrote: post #225

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. >…

There's a pervasive solution bias in thinking about climate change and this is an example of it. If reducing emissions won't work and we have to find a solution, then surely negative emissions is the answer? The problem with that is that the fact that we need a solution does not mean that a solution exists and that eliminating solutions that definitely won't work doesn't mean that the remaining ones have to work.

I'm not saying carbon capture will work. I'm saying that we won't be able to address climate change if it doesn't work. "We're totally fucked" is also a possibility.

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

#234

Post by [deleted] » Wed, May 01, 2019, 1:04 PM UTC

scottdupoy wrote: post #206

dagss wrote: post #179

Earlier quoted context omitted.

This article has nothing to do with carbon recapture. The gasoline produced from carbon is then intended for burn... This is simply an alternative electricity/power storage mechanism. But great to reduce emissions but is not intended for negative emissions (for which there is other tech)

> The gasoline produced from carbon is then intended for burn... If it's captured from the atmosphere and then burnt then surely it's zero-sum (apart from the energy cost of capture). Is this not better than releasing historically captured fossil fuels with a larger net increase in atmospheric levels? If the capturing process is net-negative in terms of CO2 emmissions then perhaps we could invest in capturing more th…

[deleted]

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

#235

Post by specialist » Wed, May 01, 2019, 1:11 PM 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. >…

"The only serious solution to climate change is carbon recapture."

Emphatic agreement.

We must capture and sequester faster than all sources of atmospheric CO2 & CH4. By every means available. To hopefully stop and then reverse the warming.

For the viewing audience, anthropogenic carbon is now but a fraction of the problem. Tundra is thawing, forests are burning, oceans are acidifying. In an accelerating positive feedback loop. All human activity could stop today and the increase would continue.

--

All the nitpicking and concern trolling and harumping doubting thomases in the replies is very discouraging.

Nukes vs point source capture vs BEVs vs blah blah blah. Yes, yes, yes. It's all needed. Like thirty years ago. Stop fussing and get on board.

How are geeks not grokking the scale of the immediate threat? Arguing about rearranging the deck chairs as the Titanic is sinking.

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

#236

Post by ajross » Wed, May 01, 2019, 1:40 PM UTC

blurbleblurble wrote: post #114

ajross wrote: post #106

Earlier quoted context omitted.

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 a…

Those links all just say that there's Li in Afghanistan. Calling it a "conflict mineral" is a particular term of social justice that implies that its extraction is directly related to the exploitation of some local population, not just that there's a putative "conflict" nearby! You just seem to be using the term to argue that people near wars should be economic pariahs who we never trade with. That's harmful, not helpful.

An of course, the overwhelming majority of Lithium production and reserves in the world are in Australia and Chile, which are notably conflict-free.

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

#237

Post by torpfactory » Wed, May 01, 2019, 2:20 PM 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. >…

How does the technology from Prometheus count as carbon recapture? We end up taking a (relative to the size of the problem) small amount of the 'extra' carbon out of the atmosphere... and then proceed to burn it and put it right back in. IMO carbon recapture only counts if the carbon gets removed permanently. But Prometheus's technology is problematic for other reasons.

Let's say that all of the $3/gallon which was quoted can be attributed to electricity cost and nothing else. At $0.12/kWh that would be turning 25kWh of electrical energy into ~36kWh of chemical energy (gasoline). Now it needs to be transported to the gas station, which costs something like 10% of the total energy content. So now we're back to ~32kWh of chemical energy delivered to the customer. They convert it into mechanical energy at 20% efficiency [1]. So you've converted 25kWh of electrical energy into 6.5kWh of mechanical energy at the customer's wheels. Meanwhile, we would be using a fuel that is interchangeable with carbon we dig out of the ground. What are the chances we limit ourselves to only the "green gasoline" and ignore the stuff in the ground?

Meanwhile electric vehicles convert ~60% [1] of the electrical energy used to charge them into mechanical energy. So you convert that 25kWh into 15kWh of mechanical energy. Energy can be generated in many ways, many of them not very green at all. Let's assume both the "green gasoline machine" and the EV charging box are powered by the same grid. You could go 2.3x as far with the EV for the same energy input.

Now if Prometheus is making "green jet fuel" I'd be interested because there isn't any obvious electrification solution to long distance air travel that seems close to commercialization.

[1] https://www.fueleconomy.gov/feg/evtech.shtml

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

#238

Post by amluto » Wed, May 01, 2019, 2:25 PM UTC

gridspy wrote: post #75

m463 wrote: post #67

Earlier quoted context omitted.

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.

There are also ICE farm and construction vehicles, airplanes, generators in rural areas, pumps, etc. Gasoline is an extremely convenient fuel.

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

#239

Post by openloop » Wed, May 01, 2019, 2:29 PM UTC

torpfactory wrote: post #237

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. >…

How does the technology from Prometheus count as carbon recapture? We end up taking a (relative to the size of the problem) small amount of the 'extra' carbon out of the atmosphere... and then proceed to burn it and put it right back in. IMO carbon recapture only counts if the carbon gets removed permanently. But Prometheus's technology is problematic for other reasons. Let's say that all of the $3/gallon which was q…

Real math.

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

#240

Post by chriswarbo » Wed, May 01, 2019, 2:33 PM 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…

> 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.

I would think busses are a very poor fit for batteries: their economics favours driving around for as long as possible (switching drivers in shifts). Any time spent charging is a waste.

This is less favourable than a consumer car, which sits around unused for most of the time (hence easily charged) and usually only makes a few short trips a day (e.g. commute).

I can understand the desire for supercapacitors on busses, since they are much quicker to charge than batteries. Putting chargers in the stops is a way to mitigate the low energy density of supercapacitors: they only need to last as far as the next charging point.

I think supercapacitors + fast charging stops makes busses very suited for electricity; but I don't think they're best suited for batteries (the fact that there are battery-powered busses shows that there's enough wiggle-room in the economics that they can work despite this unsuitability).