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> could they fuel their plant with their own product and still have net energy gain? I don't see how this is remotely possible. The synthetic diesel here is j

> could they fuel their plant with their own product and still have net energy gain? I don't see how this is remotely possible. The synthetic diesel here is just a high-density energy storage medium. It's better than batteries because it's denser and compatible with the majority of today's engines. It's also denser than H2 (which is also just a store) and easier to handle. But the plant here is not producing any energy, it's converting energy (probably electricity) into a form better suited for storage. Solar, wind, nuclear or fusion would be good sources of energy to convert into diesel, at most. It all depends on whether their process is efficient enough to be worth it.

aaronblohowiak 9y ago
to simplify: this is a (potentially) carbon-neutral "liquid battery"
jjoonathan 9y ago
There's a competing technique that has net energy gain and better economics. It does require land and water, though. > [CE's A2F] needs 100 times less land and water than biofuels ... but for it to work, it will have to reduce costs
- brians 9y ago
  Could you expand on net energy gain?
  - taneq 9y ago
    The process is driven partly by photosynthesis, rather than entirely by electricity.
    - jjoonathan 9y ago
      Right, and there's an argument to be had that corn (or what have you) is a poor solar panel, but it makes up for it by being quite good at reducing CO2. I think the research in TFA is very important -- I'm quite sure we'll be able to beat nature at this game in the long run and projects like this are how we'll figure it out -- but it's worth mentioning we have workable air-to-fuel technology right now but it has been largely abandoned because of the renewed supply of cheap oil.
deleted 9y ago
[deleted]
twic 9y ago
I remember reading a website by a group of American researchers who had designed a plant, in some detail, where a nuclear reactor drove an atmospheric-CO2-to-gasoline reaction. The gasoline it produced was expensive, but not so expensive as to be completely absurd - a rise in oil prices and a fall in nuclear energy costs could make it practical. Needless to say, i can't find it now. However, i did find this similar French work, which suggests taking advantage of the output from nuclear power plants at off-peak times: https://www.sciencedirect.com/science/article/pii/S187661021100292X https://www.sciencedirect.com/science/article/pii/S187661021...
mirimir 9y ago
> It all depends on whether their process is efficient enough to be worth it. I don't see an estimate. But: > The achilles heel of all negative emission technologies is cost. Government policy units assume that they will become economically viable, but the best hope of Carbon Engineering and other direct air extraction companies is to get the price down to $100 a tonne from the current $600. I get that $600 per tonne CO2 is about 1.7 times the current global mean price of diesel. And $100 per tonne CO2 is about 0.3 times that. Given diesel-electric conversion efficiency of ~40%, you increase those estimates 2.5 fold. And then there's the energy input for hydrogen production, and the efficiency hit for chemical conversion. It doesn't seem workable to me.

aaronblohowiak 9y ago

to simplify: this is a (potentially) carbon-neutral "liquid battery"

jjoonathan 9y ago

There's a competing technique that has net energy gain and better economics. It does require land and water, though. > [CE's A2F] needs 100 times less land and water than biofuels ... but for it to work, it will have to reduce costs

brians 9y ago
Could you expand on net energy gain?
- taneq 9y ago
  The process is driven partly by photosynthesis, rather than entirely by electricity.
  - jjoonathan 9y ago
    Right, and there's an argument to be had that corn (or what have you) is a poor solar panel, but it makes up for it by being quite good at reducing CO2. I think the research in TFA is very important -- I'm quite sure we'll be able to beat nature at this game in the long run and projects like this are how we'll figure it out -- but it's worth mentioning we have workable air-to-fuel technology right now but it has been largely abandoned because of the renewed supply of cheap oil.

deleted 9y ago

[deleted]

twic 9y ago

I remember reading a website by a group of American researchers who had designed a plant, in some detail, where a nuclear reactor drove an atmospheric-CO2-to-gasoline reaction. The gasoline it produced was expensive, but not so expensive as to be completely absurd - a rise in oil prices and a fall in nuclear energy costs could make it practical. Needless to say, i can't find it now. However, i did find this similar French work, which suggests taking advantage of the output from nuclear power plants at off-peak times: https://www.sciencedirect.com/science/article/pii/S187661021100292X https://www.sciencedirect.com/science/article/pii/S187661021...

mirimir 9y ago

> It all depends on whether their process is efficient enough to be worth it. I don't see an estimate. But: > The achilles heel of all negative emission technologies is cost. Government policy units assume that they will become economically viable, but the best hope of Carbon Engineering and other direct air extraction companies is to get the price down to $100 a tonne from the current $600. I get that $600 per tonne CO2 is about 1.7 times the current global mean price of diesel. And $100 per tonne CO2 is about 0.3 times that. Given diesel-electric conversion efficiency of ~40%, you increase those estimates 2.5 fold. And then there's the energy input for hydrogen production, and the efficiency hit for chemical conversion. It doesn't seem workable to me.