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Interesting approach, but the article is missing two magic numbers: - the cost of the device and of course - the energy needed to extract a certain amount of

by _ph_ 9y ago

Interesting approach, but the article is missing two magic numbers: - the cost of the device and of course - the energy needed to extract a certain amount of CO2 from the atmosphere. If more CO2 is released by producing the energy the device needs for CO2 capture, nothing is gained. The feasibility hinges on those two numbers. Especially, is it more efficient to capture CO2 or spend the money instead on not producing it? If the needed electricity is produced by e.g. solar, is it more efficient to use the energy to capture CO2, or rather replace some coal power plants?

epistasis 9y ago
The second number is entirely moveable depending on the source of energy. I would argue that (energy?) efficiency doesn't matter when dealing with energy extracted from the ground or from the sun or wind; what matters is the cost. The article doesn't mention the cost of extracting a ton of CO2 from the atmosphere, other than to say they have a ways to go on that front. The "cost" of carbon emissions is estimated from $25-$125/ton (Social Cost of Carbon), and financial planning from fossil fuel companies like Exxon use a cost of $80/ton. (For some more familiar numbers, $80/ton equates to about $0.80/gallon of gas, or $0.035/kWh for combined-cycle natural gas electricity). One could imagine carbon emitters paying for capture, or paying society for the costs that they impose on the rest of us. However, once you add that extra $35/MWh for natural gas electricity, renewables start to look pretty good. (For comparison, wind subsidies in Texas are around $24/MWh, so natural gas is getting a carbon subsidy than wind power gets. And unsubsidized wind and solar in the proper sites are extremely competitive cost wise.) In any case, within the next few decades at least, it's going to be cheaper to use solar+wind+storage than it is going to be to burn coal and then extract the CO2.

by _ph_ 9y ago

epistasis 9y ago

The second number is entirely moveable depending on the source of energy. I would argue that (energy?) efficiency doesn't matter when dealing with energy extracted from the ground or from the sun or wind; what matters is the cost. The article doesn't mention the cost of extracting a ton of CO2 from the atmosphere, other than to say they have a ways to go on that front. The "cost" of carbon emissions is estimated from $25-$125/ton (Social Cost of Carbon), and financial planning from fossil fuel companies like Exxon use a cost of $80/ton. (For some more familiar numbers, $80/ton equates to about $0.80/gallon of gas, or $0.035/kWh for combined-cycle natural gas electricity). One could imagine carbon emitters paying for capture, or paying society for the costs that they impose on the rest of us. However, once you add that extra $35/MWh for natural gas electricity, renewables start to look pretty good. (For comparison, wind subsidies in Texas are around $24/MWh, so natural gas is getting a carbon subsidy than wind power gets. And unsubsidized wind and solar in the proper sites are extremely competitive cost wise.) In any case, within the next few decades at least, it's going to be cheaper to use solar+wind+storage than it is going to be to burn coal and then extract the CO2.