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I wanted to do some back of the hand math on how many nuclear reactors it would take to reduce CO2 in the atmosphere to pre industrial levels after reading the article below describing the process.

Regarding this synthesis reaction: https://www.nature.com/articles/s41467-020-20214-z

From the abstract it seems to convert one mole of atmospheric CO2 into a fuel for use either in transportation or as a form of carbon capture (bury it again), it would take (-166kJ + -125kJ + 41kJ) in energy for one mole of CO2 coming to a total of 250kJ of energy required per mole turned into the various fractious products...

Next let's say we want to return the amount of CO2 to pre industrial levels IGNORING output currently, that we were in effect carbon neutral (just for the sake of argument because the numbers are getting outrageous) by 2100. That gives us 78 years to do so.

So. currently, I am reading some random internet sources saying that there is about (1.8 * 10^20) moles of CO2 in the atmosphere currently and that we are at about 400ppm compared to preindustrial levels of 280ppm. So we need a reduction of (120ppm/400ppm) == .3 or 30% reduction in atmospheric carbon from todays levels for a total reduction of (.3 * 1.8 * 10^20) moles of CO2.

Now using nuclear power as it is the most energy rich, but I think it would yield similar cost analysis for other types of power, am I correct in stating that to reduce this in 78 years we would necessarily need at least (.3 * 1.8 * 10^20) moles CO2 * (240kJ per moles CO2) energy to yield that? That would mean we would need to produce 1.29600 × 10^25 joules in 79 years, or in watts 1.29600 × 10^25J / (79*365*24*60*60s) which equals 5.20201144 × 10^15 watts.

I read somewhere the average nuclear power plant yields about 1 gigawatt. If that is true, to reduce atmospheric carbon to preindustrial levels by 2100, we would need ((1.29600 * ((10^25) J)) / (79 * 365 * 24 * 60 * (60 s))) / (1 gigawatt) which yields 5 202 011.44.

Is my off the cuff math correct? In order to return the earth to way it was, minus of course all the nuclear plants, mean that we would need to build roughly 5 million nuclear power stations?

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  • $\begingroup$ With the same constraints, assuming my crappy math is correct, it would take more land area than the surface of the earth to reduce carbon to pre industrial levels $\endgroup$
    – Erik
    Commented Nov 2, 2021 at 1:10
  • $\begingroup$ I didn't check it but wouldn't be surprised. You essentially have to invest almost all the energy used up by humanity up till this point + the inefficiencies. That would immediately put you minimum in the 10s or 100s of thousands of reactors range, so your estimation seems close in order of magnitude. CO2 recycling is a dumb plan from the beginning, but I guess attracts enough governmental and venture money, so people do it anyways. I wish we had something like self-reproducing organic material, that you can just grow from seed to solve this.:) $\endgroup$
    – Greg
    Commented Nov 2, 2021 at 3:52
  • $\begingroup$ @Erik Yeah, and it would be the largest industrial project ever, producing enormous waste and use enormous energy, raw materials in the first place. $\endgroup$
    – Greg
    Commented Nov 2, 2021 at 3:53
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    $\begingroup$ This type of "science" is just done for funding purposes. The authors will be applauded for publishing in Nature Communications in their respective departments, this will result in one or two conference invitations, the student authors will get an academic job...and the world will move on. $\endgroup$
    – ACR
    Commented Nov 2, 2021 at 4:08
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    $\begingroup$ Welcome to Chemistry! On Chemistry mathematical and chemical expressions can be formatted using MathJax (and LaTeX Syntax). If you want to know more, please have a look here and here. I have removed the meta commentary from the title, but leave the (optional) rest to you. $\endgroup$ Commented Nov 2, 2021 at 23:29

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