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Quick summary: "Given sources of Carbon and Hydrogen plus massive energy inputs, you can synthesize hydrocarbons!" I feel like the headlines always try to pret

Quick summary: "Given sources of Carbon and Hydrogen plus massive energy inputs, you can synthesize hydrocarbons!" I feel like the headlines always try to pretend you're getting energy out of the CO₂ rather than putting energy into a hydrocarbon energy storage chemical. Question of course is economics of converting some (hopefully clean-ish) energy into stored hydrocarbon chemical bond energy and then combusting it in a vehicle vs. just digging up hydrocarbons and combusting them.

ChuckMcM 4y ago
It is an answer for the complaint "but solar doesn't work at night" and "transmitting energy over long distances is inefficient" You see you could cover enough desert in Nevada with enough solar panels to provide 100% of the current electricity use of the United States. But you couldn't transmit it over the current grid to the rest of the country and it would "turn off" every night. So stupid right? Except maybe you are using that energy to create natural gas and you're shipping natural gas around through pipelines to standard gas electric power plants. The math works, and the BLM has enough land (caveat the endangered tortoises) and so it is a "technically possible" solution to carbon neutral energy (you're taking CO2 out of the air and then returning it when you burn the natural gas). This also works with fission power plants as the source of energy, and really shines with fusion power plants (fewer externalized issues like waste management).
nine_k 4y ago
In other words, given a solar or nuclear plant near a chemical / metallurgy plant, you can also produce some liquid fuels.
janef0421 4y ago
Or, if you're concerned with the climate impact of using fossil fuels, you can consider the economics of shifting to a technology that cab use the energy more directly; I.e, replacing aviation with electric railways.
drallison 4y ago
Amen. Fuel out of thin air: CO2 capture from air and converted to methanol takes way more energy than can be recovered from the created fuel.
subradios 4y ago
I think it's totally plausible actually, there's lots of stranded renewables and otherwise flared natgas that could be used for this process
- acidburnNSA 4y ago
  There are places you can get energy from to do this for sure. But you're still putting energy into an energy conversion, not getting energy out of CO₂. (Unless you're doing some kind of late stage stellar nucleosynthesis fusion, which... you're not) The headline should be: "Fuel components from air synthesized into liquid fuel using energy from some other energy source"
  - simondotau 4y ago
    An inefficient process is still infinitely more efficient than nothing. I think there’s an opportunity to formalise an excess energy marketplace, established with an inefficient process to get the ball rolling. From there, market forces can dictate winners.
    - ticviking 4y ago
      The big thing here is in theory we could put something like a nuclear plant(which people are afraid of) in a remote area and produce fuels we are already equipped to use from that pretty major energy source. Combine that with Solar storage and geo-thermal storage using that and maybe we will continue to have enough movable energy to have long distance travel that isn't wind driven.
      - ClumsyPilot 4y ago
        If you are producing fuels at remote location, solar in the sahara will be more cost efficient. Thw whole advantage of nuclear over renewables is it's reliability for powering critical infrastructure If you are producing fuels, they can be stored, reliability doesn't matter - only cost.
      - 4y ago
DennisP 4y ago
Well we might want to consider the externalities of "just digging up hydrocarbons and combusting them."
- acidburnNSA 4y ago
  Of course, and we are. But let's not pretend there is free fuel floating around in CO2 as part of that consideration.
mlindner 4y ago
I think the primary idea is that eventually we'll still need carbon source inputs for making certain things (fertilizer for one, most types of rocket fuel for another) and so this is an alternative to that. If we're not getting hydrocarbons from fossil fuels, we need to get it from somewhere else for the petrochemical industry. It's also a nice thing to do when the spot price of energy goes negative or extremely low when there's tons of surplus renewable energy. I also heard one example assuming a future with nuclear fusion being cheap and you put a nuclear fusion plant at larger airports to produce jet fuel on-site.
- credit_guy 4y ago
  > fertilizer for one Fertilizers don't contain carbon. Plants need nitrogen, potassium and phosphorus, which they can't easily get from their surroundings, so we provide these via fertilizers. They get their own carbon out of the CO2 in the air. We do need hydrogen to make fertilizers, and currently the cheapest way to make hydrogen is to start with methane, CH4. But this is just a matter of convenience.
- colechristensen 4y ago
  You don’t need carbon for fertilizer. Hydrogen is harvested from methane which is added to atmospheric nitrogen to make ammonia, the basis for all nitrogen compounds used for fertilizers. You can change the process slightly to use other sources of hydrogen but they’re considerably more expensive. If you were synthesizing anyway, you would not take a detour to methane.
  - mlindner 4y ago
    I wasn't suggesting that methane be produced.
    - colechristensen 4y ago
      What were you suggesting be produced for fertilizer inputs?
- gus_massa 4y ago
Animats 4y ago
Yeah, these articles are consistently vague about the energy inputs and outputs of the process. This isn't even a closed cycle. It uses up potassium hydroxide. Electrolyzing water into hydrogen and oxygen is more promising, if you like that sort of thing. Once you have hydrogen, you can make hydrocarbons, if you want to. That's good to have as a technology for when we use up all the natural hydrocarbons and still want to make plastics. As an energy storage system, it sucks.
- thinkcontext 4y ago
  The described process relies on hydrogen.
- photochemsyn 4y ago
  Well they get some KOH loss, true, but that's why it's called industrial process development, those kinds of things can often be solved. > "When air was bubbled through potassium hydroxide dissolved in ethylene glycol and the CO2-loaded solution subsequently hydrogenated in the presence of H2 and a metal catalyst, complete conversion to methanol was observed at 140 °C. Moreover, regeneration of the hydroxide base occurred at mild temperatures of 100-140 °C. Notably, a fraction of the base was deactivated in an unwanted side reaction. Currently, the researchers are aiming to minimize the side reactions to efficiently recycle the potassium hydroxide." Having to use large volumes of ethylene glycol might be an issue, however. There's a whole literature on this particular reaction, for example, as of 2019: https://www.frontiersin.org/articles/10.3389/fenrg.2019.00081/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.0008... > "The methanol production from direct CO2 (using pure sources of CO2 and H2) has several advantages over the conventional process—it results in significantly less byproducts, and requires less energy in product purification (Marlin et al., 2018). However, the methanol production cost via direct CO2 hydrogenation is 2–2.5 times higher than the cost of conventional process (Atsonics et al., 2015)."
photochemsyn 4y ago
The advantage is you can apply the past 100 years of organic chemistry development to specifically build whatever molecule you want without having to deal with separating out the desired hydrocarbon molecules from the complex glop called 'crude oil'. This is essentially what's going on in modern natural-gas-fed petrochemical facilities (although natural gas is often itself contaminated with sulfur and mercury species, like H2S / H2Hg etc.). The disadvantage is that there's a high energy cost involved in stripping oxygen off carbon dioxide and replacing it with hydrogen (it is storing energy in C-H and C-C bonds). As the cheap easy-to-extract oil is mostly gone at this point, however, these costs are approaching parity. The real necessary use cases of hydrocarbon fuels are for rockets and jet airplanes, as battery energy density is just too low. Long-distance oceanic shipping is another area where hydrocarbon fuels might be necessary, although there are some other options (wind/solar/iron redox).
- acidburnNSA 4y ago
  > Long-distance oceanic shipping is another area where hydrocarbon fuels might be necessary, although there are some other options (wind/solar/iron redox). Yeah, and nuclear, which is deployed at huge scale in seafaring vessels in the Navy. Merchant nuclear propulsion had an early start and is likely to see a revival imho. https://en.wikipedia.org/wiki/NS_Savannah https://en.wikipedia.org/wiki/NS_Savannah https://corepower.energy/ https://corepower.energy/ https://en.wikipedia.org/wiki/Nuclear_marine_propulsion https://en.wikipedia.org/wiki/Nuclear_marine_propulsion
  - eloff 4y ago
    Only if they can do it cheaper than the Navy. Nuclear isn't used because it saves on fuel. It's used because the operational advantages it bestows are worth more for the largest carriers and submarines than the extra cost it adds.
    - acidburnNSA 4y ago
      I agree that merchant nuclear-powered vessels will need to be cheaper than Naval nuclear-powered vessels. That is the goal. An international carbon tax or other credits for low-carbon/low-emission shipping would help.

ChuckMcM 4y ago

It is an answer for the complaint "but solar doesn't work at night" and "transmitting energy over long distances is inefficient" You see you could cover enough desert in Nevada with enough solar panels to provide 100% of the current electricity use of the United States. But you couldn't transmit it over the current grid to the rest of the country and it would "turn off" every night. So stupid right? Except maybe you are using that energy to create natural gas and you're shipping natural gas around through pipelines to standard gas electric power plants. The math works, and the BLM has enough land (caveat the endangered tortoises) and so it is a "technically possible" solution to carbon neutral energy (you're taking CO2 out of the air and then returning it when you burn the natural gas). This also works with fission power plants as the source of energy, and really shines with fusion power plants (fewer externalized issues like waste management).

nine_k 4y ago

In other words, given a solar or nuclear plant near a chemical / metallurgy plant, you can also produce some liquid fuels.

janef0421 4y ago

Or, if you're concerned with the climate impact of using fossil fuels, you can consider the economics of shifting to a technology that cab use the energy more directly; I.e, replacing aviation with electric railways.

drallison 4y ago

Amen. Fuel out of thin air: CO2 capture from air and converted to methanol takes way more energy than can be recovered from the created fuel.

subradios 4y ago

I think it's totally plausible actually, there's lots of stranded renewables and otherwise flared natgas that could be used for this process

acidburnNSA 4y ago
There are places you can get energy from to do this for sure. But you're still putting energy into an energy conversion, not getting energy out of CO₂. (Unless you're doing some kind of late stage stellar nucleosynthesis fusion, which... you're not) The headline should be: "Fuel components from air synthesized into liquid fuel using energy from some other energy source"
- simondotau 4y ago
  An inefficient process is still infinitely more efficient than nothing. I think there’s an opportunity to formalise an excess energy marketplace, established with an inefficient process to get the ball rolling. From there, market forces can dictate winners.
  - ticviking 4y ago
    The big thing here is in theory we could put something like a nuclear plant(which people are afraid of) in a remote area and produce fuels we are already equipped to use from that pretty major energy source. Combine that with Solar storage and geo-thermal storage using that and maybe we will continue to have enough movable energy to have long distance travel that isn't wind driven.
    - ClumsyPilot 4y ago
      If you are producing fuels at remote location, solar in the sahara will be more cost efficient. Thw whole advantage of nuclear over renewables is it's reliability for powering critical infrastructure If you are producing fuels, they can be stored, reliability doesn't matter - only cost.
    - 4y ago

DennisP 4y ago

Well we might want to consider the externalities of "just digging up hydrocarbons and combusting them."

acidburnNSA 4y ago
Of course, and we are. But let's not pretend there is free fuel floating around in CO2 as part of that consideration.

mlindner 4y ago

I think the primary idea is that eventually we'll still need carbon source inputs for making certain things (fertilizer for one, most types of rocket fuel for another) and so this is an alternative to that. If we're not getting hydrocarbons from fossil fuels, we need to get it from somewhere else for the petrochemical industry. It's also a nice thing to do when the spot price of energy goes negative or extremely low when there's tons of surplus renewable energy. I also heard one example assuming a future with nuclear fusion being cheap and you put a nuclear fusion plant at larger airports to produce jet fuel on-site.

credit_guy 4y ago
> fertilizer for one Fertilizers don't contain carbon. Plants need nitrogen, potassium and phosphorus, which they can't easily get from their surroundings, so we provide these via fertilizers. They get their own carbon out of the CO2 in the air. We do need hydrogen to make fertilizers, and currently the cheapest way to make hydrogen is to start with methane, CH4. But this is just a matter of convenience.
colechristensen 4y ago
You don’t need carbon for fertilizer. Hydrogen is harvested from methane which is added to atmospheric nitrogen to make ammonia, the basis for all nitrogen compounds used for fertilizers. You can change the process slightly to use other sources of hydrogen but they’re considerably more expensive. If you were synthesizing anyway, you would not take a detour to methane.
- mlindner 4y ago
  I wasn't suggesting that methane be produced.
  - colechristensen 4y ago
    What were you suggesting be produced for fertilizer inputs?
gus_massa 4y ago

Animats 4y ago

Yeah, these articles are consistently vague about the energy inputs and outputs of the process. This isn't even a closed cycle. It uses up potassium hydroxide. Electrolyzing water into hydrogen and oxygen is more promising, if you like that sort of thing. Once you have hydrogen, you can make hydrocarbons, if you want to. That's good to have as a technology for when we use up all the natural hydrocarbons and still want to make plastics. As an energy storage system, it sucks.

thinkcontext 4y ago
The described process relies on hydrogen.
photochemsyn 4y ago
Well they get some KOH loss, true, but that's why it's called industrial process development, those kinds of things can often be solved. > "When air was bubbled through potassium hydroxide dissolved in ethylene glycol and the CO2-loaded solution subsequently hydrogenated in the presence of H2 and a metal catalyst, complete conversion to methanol was observed at 140 °C. Moreover, regeneration of the hydroxide base occurred at mild temperatures of 100-140 °C. Notably, a fraction of the base was deactivated in an unwanted side reaction. Currently, the researchers are aiming to minimize the side reactions to efficiently recycle the potassium hydroxide." Having to use large volumes of ethylene glycol might be an issue, however. There's a whole literature on this particular reaction, for example, as of 2019: https://www.frontiersin.org/articles/10.3389/fenrg.2019.00081/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.0008... > "The methanol production from direct CO2 (using pure sources of CO2 and H2) has several advantages over the conventional process—it results in significantly less byproducts, and requires less energy in product purification (Marlin et al., 2018). However, the methanol production cost via direct CO2 hydrogenation is 2–2.5 times higher than the cost of conventional process (Atsonics et al., 2015)."

photochemsyn 4y ago

The advantage is you can apply the past 100 years of organic chemistry development to specifically build whatever molecule you want without having to deal with separating out the desired hydrocarbon molecules from the complex glop called 'crude oil'. This is essentially what's going on in modern natural-gas-fed petrochemical facilities (although natural gas is often itself contaminated with sulfur and mercury species, like H2S / H2Hg etc.). The disadvantage is that there's a high energy cost involved in stripping oxygen off carbon dioxide and replacing it with hydrogen (it is storing energy in C-H and C-C bonds). As the cheap easy-to-extract oil is mostly gone at this point, however, these costs are approaching parity. The real necessary use cases of hydrocarbon fuels are for rockets and jet airplanes, as battery energy density is just too low. Long-distance oceanic shipping is another area where hydrocarbon fuels might be necessary, although there are some other options (wind/solar/iron redox).

acidburnNSA 4y ago
> Long-distance oceanic shipping is another area where hydrocarbon fuels might be necessary, although there are some other options (wind/solar/iron redox). Yeah, and nuclear, which is deployed at huge scale in seafaring vessels in the Navy. Merchant nuclear propulsion had an early start and is likely to see a revival imho. https://en.wikipedia.org/wiki/NS_Savannah https://en.wikipedia.org/wiki/NS_Savannah https://corepower.energy/ https://corepower.energy/ https://en.wikipedia.org/wiki/Nuclear_marine_propulsion https://en.wikipedia.org/wiki/Nuclear_marine_propulsion
- eloff 4y ago
  Only if they can do it cheaper than the Navy. Nuclear isn't used because it saves on fuel. It's used because the operational advantages it bestows are worth more for the largest carriers and submarines than the extra cost it adds.
  - acidburnNSA 4y ago
    I agree that merchant nuclear-powered vessels will need to be cheaper than Naval nuclear-powered vessels. That is the goal. An international carbon tax or other credits for low-carbon/low-emission shipping would help.