4 ms·

I posted this for a couple of reasons. I'd like to know, why is it still not economical? Has any progress been made? How much progress can be made (like how doe

I posted this for a couple of reasons. I'd like to know, why is it still not economical? Has any progress been made? How much progress can be made (like how does this compare to plants? Maybe we're just better off going the algae route or whatever)? In any case, maybe it's just a pipe dream but it would be really convenient if our needs for energy storage (that's how I see this) could be met with something that incentivizes cleaning up the environment. I don't see why it matters that oil companies are involved if they have the resources and power to do this. The fact that they obviously need to be reined in is as far as I can tell entirely orthogonal.

pif 4y ago
> why is it still not economical? Entropy and energy. - Entropy: dispersing is easy, collecting is hard. - Energy: burning releases energy, putting it back together requires energy.
- guerrilla 4y ago
  No, this is not a useful or interesting response. We have in many places at many times of the day extreme excesses energy (with free electricity and often negative prices in some regions), especially in places with high winds at night (when industry isn't consuming as much.) In many of these situations, our biggest problem is a lack of energy storage rather than power. There comes a point where the cost in losses becomes low enough, what is that point and what factors are involved.
  - prewett 4y ago
    I think the fact that unburning CO2 requires input of energy is a salient factor. You can get 12 g of carbon for 22.4 L of CO2. 1 L (liquid) of gasoline weighs about 750 g. So to get 1 L of gasoline you will need to process at least 63 L of CO2, and since there are about 400 ppm of CO2 in air (that is, 400 / 1e6 = 0.0004), you will need to process 158,000 L of air for one L of gasoline. Assuming 100% efficiency. A box fan can do 70,000 L of air in a minute, so 26.6 L of gasoline/hr (7.0 gal/hr). At a price of $4/gal, this is $28/hr, if electricity is free, you have 100% efficiency, and you can sell the gasoline for retail prices without transporting it. Obviously, you'll need to scale this up. But how long does this take to recoup your capital investment in the equipment and R&D? And would it be more profitable just to buy some KO/AAPL/BERK/QQQ stock? Or buy some real-estate, or whatever other investment possibilities there are? But is electricity really free? And for how long, in what location? What are the transport costs from that location? If you can only profitably produce 8 hours of the day (e.g. night, as hypothesized), it takes three times as long to pay back your investment. Multiply that by at least 2, since I think 100% efficiency is unlikely (I think 50% is unlikely, too, but I'll be generous). There is also the problem of how do you ensure that you aren't "polluting" the area around your intake with CO2-free air.
    - tonyarkles 4y ago
      Just a quick math note for other readers. There's a multiplication missing on the "at least 63L of CO2". That should be 22.4L*750g/12g = 1400L of CO2 I think.

pif 4y ago

> why is it still not economical? Entropy and energy. - Entropy: dispersing is easy, collecting is hard. - Energy: burning releases energy, putting it back together requires energy.

guerrilla 4y ago
No, this is not a useful or interesting response. We have in many places at many times of the day extreme excesses energy (with free electricity and often negative prices in some regions), especially in places with high winds at night (when industry isn't consuming as much.) In many of these situations, our biggest problem is a lack of energy storage rather than power. There comes a point where the cost in losses becomes low enough, what is that point and what factors are involved.
- prewett 4y ago
  I think the fact that unburning CO2 requires input of energy is a salient factor. You can get 12 g of carbon for 22.4 L of CO2. 1 L (liquid) of gasoline weighs about 750 g. So to get 1 L of gasoline you will need to process at least 63 L of CO2, and since there are about 400 ppm of CO2 in air (that is, 400 / 1e6 = 0.0004), you will need to process 158,000 L of air for one L of gasoline. Assuming 100% efficiency. A box fan can do 70,000 L of air in a minute, so 26.6 L of gasoline/hr (7.0 gal/hr). At a price of $4/gal, this is $28/hr, if electricity is free, you have 100% efficiency, and you can sell the gasoline for retail prices without transporting it. Obviously, you'll need to scale this up. But how long does this take to recoup your capital investment in the equipment and R&D? And would it be more profitable just to buy some KO/AAPL/BERK/QQQ stock? Or buy some real-estate, or whatever other investment possibilities there are? But is electricity really free? And for how long, in what location? What are the transport costs from that location? If you can only profitably produce 8 hours of the day (e.g. night, as hypothesized), it takes three times as long to pay back your investment. Multiply that by at least 2, since I think 100% efficiency is unlikely (I think 50% is unlikely, too, but I'll be generous). There is also the problem of how do you ensure that you aren't "polluting" the area around your intake with CO2-free air.
  - tonyarkles 4y ago
    Just a quick math note for other readers. There's a multiplication missing on the "at least 63L of CO2". That should be 22.4L*750g/12g = 1400L of CO2 I think.