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173 points rbanffy | 1 comments | | HN request time: 0s | source
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VyseofArcadia ◴[] No.42127346[source]
Time scale is also something I want to know about. "Can I remove CO2 from the air and turn it into something valuable in a way that is cost effective?" is one question. Another question is, "Can I remove CO2 from the air and turn it into something valuable faster than a tree?"
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danbruc ◴[] No.42128010[source]
I have not thought about this too carefully so I might be overlooking something. With that out of the way, a quick search indicates that we burn about 90 % of gas, oil, and coal for one purpose or another. Let's round this and pretend we burn it all. To undo this we will essentially need the same amount of energy again that we got out of it when we burned it, we would need to use all the energy coming from fossil fuels to undo burning them. Conservation of energy essentially.

Which makes it obvious that the entire idea is pretty pointless, burn fossil fuels to generate energy to then use it to unburn fossil fuels. To do it with renewable energy, we still need the same capacity as the fossil fuel capacity and when we have that - ignoring issues like fluctuations in renewable sources - it makes more sense to just use the renewable sources directly instead of using them to undo burning fossil fuels.

If you want to use the process to pull carbon out of the atmosphere, then you first have to replace all fossil fuels with renewable ones, then you can use additional renewable capacity to remove carbon. Add additional 10 % capacity to the world energy capacity to undo one year of carbon emissions every decade, at least to a first approximation.

To come back to the initial question, you essentially need an industry the same order of magnitude as the fossil fuel industry to have a meaningful impact. Not going to happen anytime soon.

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1. TSiege ◴[] No.42128237[source]
The point that you're missing is that changes this equation a bit is that burning fossil fuels wastes most of the energy as heat another waste of energy is the amount of FFs we use to ship FFs to other places. So together that means we don't need the same amount of electric power to do the same amount of work. That being said, keeping fossil fuels in the ground will always be better than removing CO2 for the reasons you said. We also seem to be growing energy demands instead of shrinking or stabilizing them which also makes the transition harder.