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Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

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Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#331

Post by ummonk »

>About 3 years ago I realized it could do this job, but it wasn’t clear that a startup could raise money for such an ambitious effort, especially one linked to a political issue (unfortunately) like climate change.

That is probably true, but unfortunate. FWIW I’m a major skeptic as to the harms of climate change, but I still find your startup very exciting. Whether or not climate change is an issue, having a renewable cost effective way to convert energy into hydrocarbons would be amazing!

I’m curious whether you’re sticking to just focusing on the energy use case or continuing to develop other use cases such as the earlier desalination. There are likely lots of areas in industry where such membrane technology would provide a useful tool in the arsenal of methods to separate chemicals.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#332

Post by _Nat_ »

rmcginnis wrote: post #322
_Nat_ wrote: post #320

Why open-air capture? I mean, it's typically much cheaper to capture CO2 from concentrated streams, such as the flue gases from coal-fired power plants. So why accomplish the same CO2 mitigation at higher cost by getting it from open-air capture?

We want to get to >300 B gallons per year of gasoline, and only direct air capture will scale to that level.

Even in the long term, it seems like you'd want to grab CO2 from point-sources. Sure you might need to also grab CO2 from open-air if you reach such a scale, but even at that point open-air would just be a supplement rather than the sole source (unless there's a reason to favor open-air exclusively?).

So why start with open-air capture? Just seems weird to burn cash on a more expensive way of accomplishing the same goal.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#333

Post by rmcginnis »

tomxor wrote: post #317

What are the major challenges you have yet to face to make it economically viable? e.g manufacturing your nano material at scale or obtaining higher efficiency..

There are no limiting factors to us scaling now.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#334

Post by rmcginnis »

ummonk wrote: post #331

>About 3 years ago I realized it could do this job, but it wasn’t clear that a startup could raise money for such an ambitious effort, especially one linked to a political issue (unfortunately) like climate change. That is probably true, but unfortunate. FWIW I’m a major skeptic as to the harms of climate change, but I still find your startup very exciting. Whether or not climate change is an issue, having a renewabl…

I'm focused on Prometheus and turning CO2 to fuel, but my previous company Mattershift will make the membranes available for other uses.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#335

Post by blazespin »

rmcginnis wrote: post #322
_Nat_ wrote: post #320

Why open-air capture? I mean, it's typically much cheaper to capture CO2 from concentrated streams, such as the flue gases from coal-fired power plants. So why accomplish the same CO2 mitigation at higher cost by getting it from open-air capture?

We want to get to >300 B gallons per year of gasoline, and only direct air capture will scale to that level.

Yeah, but your capture system will have to be insanely massive. Have you estimated how much air you’ll have to churn through? What risks are there to local fauna? You’ll have to collocate these all over the world.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#336

Post by thereisnospork »

rmcginnis wrote: post #282
thereisnospork wrote: post #185

If you really think the underlying economic problem with electrochemical CO2 to alcohols as fuel is the separation at the end you are in for a world of (economic) hurt. Not that improving the aforementioned separation isn't useful or valuable, its just not the lynch pin. Take a really hard look at your economics, in particular throughput and capital amortization (which scales proportionally to uptime!). Good comparis…

The separation itself is not the only thing that makes the economics favorable. It's important that changing the separation makes the process electricity only overall, and this is a big deal. We can run intermittently, allowing low renewable power costs, and since there is no pressure or heat in the system, we can use inexpensive components. When the capex is low, it allows for a lot of other things to not be ideal s…

Electricity costs more than heat, as a rule. (electricity = heat at pretty much 100% efficiency)

Intermittent operation blows up CAPEX costs.

There's no heat in the system until you start dumping electricity into the resistive heating of your cells - you won't ever be able to run at scale at room temperature. A gallon of gas per second unit - something nicely sized for intermittent operation at a gas station - would need to vent approximately 120 megawatts of heat.

Current densities are 1-2 OOM lower than water electrolyzer.

Cell CAPEX isn't nearly as catalyst dependent as the daily 'We've invented a replacement for platinum in fuel cells' papers would make you believe. Nafion, balance of hardware, and assembly man-hours are $$$.

I've been where you are (more or less): beware the superficially justifiable assumptions.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#337

Post by rmcginnis »

thereisnospork wrote: post #336
rmcginnis wrote: post #282

Earlier quoted context omitted.

The separation itself is not the only thing that makes the economics favorable. It's important that changing the separation makes the process electricity only overall, and this is a big deal. We can run intermittently, allowing low renewable power costs, and since there is no pressure or heat in the system, we can use inexpensive components. When the capex is low, it allows for a lot of other things to not be ideal s…

Electricity costs more than heat, as a rule. (electricity = heat at pretty much 100% efficiency) Intermittent operation blows up CAPEX costs. There's no heat in the system until you start dumping electricity into the resistive heating of your cells - you won't ever be able to run at scale at room temperature. A gallon of gas per second unit - something nicely sized for intermittent operation at a gas station - would…

It's true that running part of the time is not as good as running continuously, but if the capital is low enough, it's ok to start out running intermittently until we get to the point where we have low cost dedicated power and can have a higher uptime.

We will have to shed heat from the system to the environment, but that can be done passively.

Current densities are likely going to be substantially lower, but our capital costs are also going to be much lower. We don't need to operate at 30 bar for example, nor further compress our product.

Our capital costs aren't magic, they're just good enough in balance with everything else.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#338

Post by __d »

rmcginnis wrote: post #311
0000011111 wrote: post #307

As a person with a background in Environmental Studies, a c o2 to fuel conversion technology such as this sounds revolutionary! I am most curious about the fundementals. Can you give us more specifics on the process such as; 1. What is the scale of the operation? Does this process need to be done at a large scale to work out economically? 2. Take a Boeing 737 for example which has a fuel capacity of ~6,875 Gallons. H…

The smallest scale at which we can operate profitably is probably in the 100,000 gallon/year range, although that could go down over time. We will make modular, mobile systems that don't have to be very big to be profitable. One shipping container will likely be able to do 100,000 gal/yr for example. The electricity required will be approx. 60 kWh/gallon.

"60kWh/gallon" -- is that gallon of gasoline? Or ethanol? Or CO2?

If you know the figures off-hand (to save me doing the chemistry), how much water and CO2 is required to produce the gallon of output?

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#339

Post by effie »

Robotbeat wrote: post #212
semi-extrinsic wrote: post #73

Earlier quoted context omitted.

The main thing that's turned me positive on "e-fuels" is that there's such a huge amount of petroleum that's used today in applications where we basically have no other options . Think stuff like big jets, or container ships. If you sit down and crunch the numbers for any non-carbon energy carrier, you either end up sinking the ship or with a fuel tank twice the size of the cargo.

The problem with e-fuels for jets is that a majority of the climate forcing comes from the high altitude water vapor in the exhaust, not actually the CO2. EDIT: I should point out here you COULD actually make an e-fuel without hydrogen and thus without water vapor as a combustion product. Carbon monoxide, for instance. The energy density is much lower, but it is sufficient. HOWEVER, there are obvious safety concerns…

CO2 seems much worse pollutant than water long term, because it stays in the air. Water at high altitudes condenses, reflects some radiation back to space and then falls back down.

Re: Launch HN: Prometheus (YC W19) – Remove CO2 from Air and Turn It into Gasoline

#340

Post by rmcginnis »

__d wrote: post #338
rmcginnis wrote: post #311

Earlier quoted context omitted.

The smallest scale at which we can operate profitably is probably in the 100,000 gallon/year range, although that could go down over time. We will make modular, mobile systems that don't have to be very big to be profitable. One shipping container will likely be able to do 100,000 gal/yr for example. The electricity required will be approx. 60 kWh/gallon.

"60kWh/gallon" -- is that gallon of gasoline? Or ethanol? Or CO2? If you know the figures off-hand (to save me doing the chemistry), how much water and CO2 is required to produce the gallon of output?

Gasoline. Each metric ton of CO2 corresponds to approx. 113 gallons of gasoline. The amount of water is approx. 1:1 by volume.
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