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It seems that the Sabatier reaction solves the biggest problem of climate change — it does create clean gas and hydrogen fuel from the captured carbon dioxide and water (from melting ice).

$$\ce{CO2 + 4H2 -> CH4 + 2H2O}$$

Currently, there is temporal overproduction of clean energy and problems with its storage. E.g., some countries (in Eastern Europe) have stopped support for new solar panel parts because the current electricity systems cannot cope with the overproduction of solar electricity, especially during the spikes. Why is there no industrial deployment of this reaction?

I can imagine several challenges that can be too difficult to overcome:

  • $\ce{CO2}$ is plentiful but there may be no process to capture it from the air and such sucking can have a bad impact on local regions (all the $\ce{CO2}$ is sucked from some region and there is no sufficient amount left for plants and crops)

  • The reaction requires $3\,\pu{MPa}$ pressure and it may be impossible to achieve such high pressure.

  • The reaction requires some catalysts. While $\ce{Ni}$ is mentioned, it itself is costly and may require replacement with costly rare earth catalysts.

I have no idea about all of this. But the idea seems to miraculous not to think about it.

There is already a more general question that was asked 10 years ago. My question is more specific and the situation has changed. Especially - my question exclude the energy as challenge. While the cost of energy can be high (e.g., in NordPool 2022), generally there are solar panel solutions that are not being adapted because of the energy storage and flow unreliability problem. So, the cost of energy stems mostly from the problem of storage and not from the global availability of electricity. As I said, some countries have withdrawn support for solar panels and explicitly states that no new solar panels can be connected to the grid. So, the energy challenge should be considered as solved in case of my question.

Note added: while the energy storage is an important point and application of methane production, my question is concerned about methane production proper. We can and we should abandon the fossil fuels but - as I understand - methane is used as important input in other chemical processes and manufacturing (non-energy use, especially in Germany) and that is why it may be required to produce it because of its own merit. It is though, interesting, that the wiki page of non-energy of methane https://en.wikipedia.org/wiki/Methane#Chemical_feedstock does not give any valuable information. It gives many hints how methane is used for the production of H2 which is used further for the fertilizers, but such use of methane can be replaced by other input and that is why methane can be avoided in that use as well. But in any case - I guess that there may be chemical processes which require methane without alternatives and that is why methane production can be beneficial.

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    $\begingroup$ You got the reaction wrong. It is: $$\ce{CO2 + 4H2 -> CH4 + 2H2O}$$ while hydrogen is often produced by $$\ce{CH4 + H2O -> CO + 3H2}$$ $\endgroup$
    – Poutnik
    Jul 30, 2022 at 13:17
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    $\begingroup$ It would consume a lot of energy. It would make sense only with excess of energy from other than fossil fuel sources. $\endgroup$
    – Poutnik
    Jul 30, 2022 at 13:36
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    $\begingroup$ Then it could be better to stay at hydrogen.... $\endgroup$
    – Poutnik
    Jul 30, 2022 at 15:02
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    $\begingroup$ Somewhat related $\endgroup$ Jul 30, 2022 at 15:17
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    $\begingroup$ See hklaw.com/en/insights/publications/2021/03/… for a discussion of using hydrogen to store excess energy from renewables. No need to involve the CO2 $\endgroup$
    – Andrew
    Jul 30, 2022 at 22:51

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The primary barrier to all related reactions is their economics

There are a number of ways to produce useful synthetic hydrocarbons from various carbon-containing sources. The Sabatier reaction might look like an attractive way to use up carbon dioxide and generate one useful hydrocarbon feedstock, but it suffers from the same economic barriers as those other reactions.

The biggest problem with all of them is the amount of energy that is required to drive the reaction forward. Despite this some of the alternatives have been used in bulk to create hydrocarbons in restricted circumstances. Usually because war or international sanctions inhibiting access to oil or gas prevents access to the (far cheaper) natural sources of the critical hydrocarbon products. So WW2 germany and apartheid-era south Africa both used some of these reactions to make fuel, despite their expense.

The Sabatier reaction faces even more economic problems that those other processes. It needs a concentrated source of carbon dioxide: that costs energy and capital. The core reaction also uses a great deal of both energy and capital equipment. And the product, methane, is–even now–relatively cheap and available from the oil industry. So, even if the energy were very cheap, it is hard to see the economics stacking up to make it the best way of producing methane.

Plus, we already have a known way to convert carbon dioxide into useful feedstocks: growing plants. They don't even need us to concentrate the carbon dioxide. Even the energy needed to convert biomass into methane would be less than the cost of the Sabatier reaction (were methane really the desired product).

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