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

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

#101

Post by geofft » Mon, May 06, 2019, 8:02 PM UTC

ineedasername wrote: post #69

rmcginnis wrote: post #45

Earlier quoted context omitted.

There is no waste. The only inputs are water, CO2, and electricity. The only outputs are fuel and oxygen.

With respect, that answer skirts the question of what happens to the water. You said you're using the nanotube membrane to separate petro products from the water. What do you do with the water left over? What state is the water in when the process is complete? Potable? In need of treatment by traditional water treatment facilities?

I think you're asking a different question from the one being responded to (and the one being responded to is more obvious to me): I will try to help this conversation by restating the questions, both of you should correct me if I've misread this.

Your question is, in the distillation step, the nanotube membrane separates fuel from water, leaving some amount of water; what happens to that water in the process?

The question that was answered was, what happens to waste water? For which the answer is that there is no water "left over", and so the question of what happens to it is ill-defined because it doesn't exist.

So I guess what is happening is that any water left in the aqueous electrolyte can continue to be used in the process indefinitely, and there is no point at which the water becomes waste water? That all the water collected from the air gets broken up into hydrogen (in the fuel) and oxygen (waste product, sent into the atmosphere) and the amount of water in the aqueous electrolyte doesn't grow?

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

#102

Post by zaroth » Mon, May 06, 2019, 8:03 PM UTC

calvinmorrison wrote: post #81

llukas wrote: post #68

Earlier quoted context omitted.

ICE cars cant compete with convenience of: * not needing to refuel * less maintenance needed * not spewing particulates in air etc (if you care about what you breathe)

* not needing to refuel no, we're taking Soothing30MinuteRelaxingBreaksAt200MileIntervalsAwesomeHappy™ brought to you by Tesla™ instead

I don't know about you. I've driven the last 5 months / 5,000 miles without using a Supercharger once, except for the first day I took delivery just to try it out.

It's there when I need it for the long road trip. But daily life is effectively refueling-free.

What percentage of round-trips are under 200 miles? NHTS recorded the distance from ~750,000 car trips in 2009 and found the 95th percentile is 30 miles, and the 99th percentile is 70 miles. Somewhere on the order of 1 in 1,000 trips needs a Supercharger stop along the way.

[1] - https://nhts.ornl.gov/vehicle-trips

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

#103

Post by 34k5jo3i4toig » Mon, May 06, 2019, 8:04 PM UTC

rmcginnis wrote: post #27

34k5jo3i4toig wrote: post #18

IMHO this is a waste of time. You are wasting clean energy sources to make dirty ones -- at best a 50-60% loss of energy. And you end up with dirty fuel, that further produces CO2, in which the cycle repeats, with a net loss. In the near future, cars and trucks will be electric. This is shuffling deckchairs on the titanic. Why not put 100% of your efforts into electric vehicles powered by 100% renewable sources?

If we want to stay below 2 degrees C in warming, we don't have time to replace the existing vehicle fleet (approx. 1.2 billion cars, trucks, buses, etc) with electric vehicles. If we instead replace the fuel, this can be fast enough. Even if all vehicles are electric in the future, this is still the right thing to do now.

My issue is that this is a step in the wrong direction, it is incentivizing the current dirty status quo. Why would anyone replace their dirty engine if they can feel good about by using your 'cleaned' fuel.

I agree we need to do something now, but this is just putting off the inevitable. Re-engineering dirty fuel sources doesn't buy us time to resolve this. It is procrastinating, shuffling titanic deckchairs.

The main advantage of this tech I can see is making 'primary' sourced fuel illegal, 'secondary' sourced fuel like this prohibitively expensive, and forcing everyone to go pure electric engine by economy.

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

#104

Post by refurb » Mon, May 06, 2019, 8:05 PM UTC

Interesting timing of Derek's Lowe's post on "In the pipeline".[1]

There are government levers (subsidies, tax breaks, carbon use taxes and so on) that can change the economic landscape, but the paper estimates that you’d need electrochemical efficiencies of at least 60% and electricity available at 4 cents/kilowatt-hr or better to make these ideas profitable (with the usual 30-year-amortization assumption about the plants themselves). How close are we? Many of the processes are currently in the 40-50% efficiency range, and need further scale-up work: within sight, but not there yet. And renewable electricity costs vary a great deal by region. The best cases are getting down around that figure, though, and continuing to improve.

[1]https://blogs.sciencemag.org/pipeline/archives/2019/05/06/sw...

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

#105

Post by qmanjamz » Mon, May 06, 2019, 8:05 PM UTC

llukas wrote: post #68

docker_up wrote: post #29

Earlier quoted context omitted.

Don't skate to where the puck is, skate to where the puck is going to be. Electric cars can't compete against gasoline cars until the price hits about $6/gallon. And considering that crude prices are relatively low, but gas in CA is almost $4/gallon in the Bay Area, it doesn't take much time for normal rates to hit $6/gallon in the next 10 years or so. At that price, it becomes more economic and that's the time frame…

ICE cars cant compete with convenience of: * not needing to refuel * less maintenance needed * not spewing particulates in air etc (if you care about what you breathe)

Bizarre comment. Being able to quickly refuel is one of the key advantages internal combustion engines have over electrics.

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

#106

Post by hoorayimhelping » Mon, May 06, 2019, 8:06 PM UTC

teej wrote: post #38

I don't have anything new to add, other than to say - this is a very well written startup pitch. I'm in awe of how clearly you've laid out the opportunity.

The only thing I have to add here is that a random stranger from the internet is rooting for you. This post sounds awesome and has all the makings of a classic American success story. Good luck!

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

#107

Post by rmcginnis » Mon, May 06, 2019, 8:06 PM UTC

mrguyorama wrote: post #89

rmcginnis wrote: post #60

Earlier quoted context omitted.

If we replace fossil gasoline with renewable gasoline, that reduces CO2 emissions. Our gasoline will be zero carbon, and may actually be certified as slightly negative, as we will not be emitting CO2 from drilling and refining as fossil fuels do. If we replace all liquid fuels now made from oil with fuels made from air mining of CO2, it could reduce emissions by approx. 10 gigatons per year. That is huge. The membran…

>If we replace fossil gasoline with renewable gasoline, that reduces CO2 emissions Nitpick: It will leave carbon emissions unchanged, but may reduce the amount added to the carbon cycle. What kind of production quantity are you looking at? Small batch aviation fuel for a niche "green" airline? Every semi truck on the road in America? The neighbor kid's go-kart? You give an "efficiency" of 60ish %, but I don't know ho…

We are going for the whole gasoline, jet fuel, and diesel market. The 100% efficient energy content of gasoline is approx. 34 kWh/ gallon. At 60% efficiency in converting renewable electricity to chemical energy, that would be approx. 57 kWh/gal.

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

#108

Post by apo » Mon, May 06, 2019, 8:06 PM UTC

I'm skeptical, but fascinated by what you're doing.

It sounds like all of the steps of your process are known, except:

1. CO2 fixation uses only electricity - no natural gas or other fossil fuels. It works at room temperature.

2. Distillation of the immediate products (alcohols) is not necessary. A carbon nanotube membrane solves the problem at room temperature through reverse osmosis.

Correct?

If so, then why target fuels rather than alcohol production directly? Burning gasoline puts the CO2 right back into the atmosphere, which seems like a half measure.

Why not focus on delivering CO2-negative organic feedstocks instead and possibly tap into the carbon credits market?

Edit: another question. How much flexibility/control does your process give over the kinds of alcohols you produce? For example, can you select for long chain alcohols over short? Saturated vs. unsaturated? Cyclic vs acyclic? Aromatic? Mono- vs oligohydroxylated hydrocarbons. Primary, secondary, tertiary? etc.

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

#109

Post by 34k5jo3i4toig » Mon, May 06, 2019, 8:06 PM UTC

tathougies wrote: post #85

34k5jo3i4toig wrote: post #18

IMHO this is a waste of time. You are wasting clean energy sources to make dirty ones -- at best a 50-60% loss of energy. And you end up with dirty fuel, that further produces CO2, in which the cycle repeats, with a net loss. In the near future, cars and trucks will be electric. This is shuffling deckchairs on the titanic. Why not put 100% of your efforts into electric vehicles powered by 100% renewable sources?

Can you elaborate how gasoline is 'dirty' if the outputs were converted back into the fuel via carbon neutral means? Such technology would make gasoline have no output, since the ouptuts would be reabsorbed. If anything, electric cars, due to the massive environmental damage due to rare earth mineral mining, would be more of an environmental disaster.

Every cycle has a 50% cost in renewable power. This is close to being carbon neutral, but it is not entirely. Its not a closed loop. You have a growing loss every cycle. Its digging yourself deeper every time.

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

#110

Post by rmcginnis » Mon, May 06, 2019, 8:08 PM UTC

mrguyorama wrote: post #98

rmcginnis wrote: post #84

Earlier quoted context omitted.

We'll need a lot more wind and solar, so Prometheus will drive the expansion of these. We'll start out taking intermittent power that's low cost (wind at midnight, for example), but will soon have resources built for us to expand. This will be good for displacing other fossil fuel use (other than transportation), as we will be increasing the availability of renewable power, and also solving the problem of being able…

Wouldn't you have to really be paying above market rates to "drive" the expansion of renewables? Any thoughts about essentially building/running your own renewable power facilities?

We will just have to agree to a purchase power agreement (PPA), and others will build the renewable power plants for us. We will be going for very large scale, so will help to drive electricty prices down from where they are now. There is a lot of competition to build renewable power plants.