Taking CO2 out of the air would be an absurdly expensive way to fight climate change

[NickB79]

https://www.theverge.com/2024/4/11/24127331/carbon-dioxide-removal-costs-rhodium-group-report

Attempting to filter enough carbon dioxide out of the atmosphere to make a significant impact on climate change would require hundreds of billions of dollars in government spending, according to a new report.

The suite of technologies emerging to attempt that task all fall under an umbrella called carbon dioxide removal, or CDR. It’s still risky and astronomically expensive. But there’s been growing chatter about it, particularly as the US continues producing record amounts of oil and gas.

According to the new report by research firm Rhodium Group, the US needs to spend roughly $100 billion a year on CDR in order to scale up to a level that would help the country meet its climate goals. A majority of that needs to come in the form of supportive policies like tax credits and procurement programs.

It's largely greenwashing hopium designed to trick us into thinking we can take our time cutting emissions, when in reality we can't.

[NNadir]

1. In the case where fossil fuels have not been banned, it is indeed too expensive. Nevertheless without fossil fuels...

...it's both feasible and desirable and probably quite affordable.

In the case where fossil fuels are banned - which is feasible if unpopular - with increased exergy recovery from high temperature systems, it is feasible for the purpose of restoring what can be restored. In particular, using a Brayton cycle in power plants with air as the working fluid offers a spectacular opportunity for accomplishing this, substituting nuclear heat for combustion heat can under the right circumstances remove carbon dioxide from the air. This carbon dioxide can then be utilized as a starting material to replace those found in coal, gas, and oil.

The case can be made even stronger if seawater is involved.

A third case is dry reforming, in a modified Allam cycle, driven not by combustion but by pyrolytic heat in a CO₂ Brayton device.

The concept is process intensification.

I support DAC and DSC (direct seawater capture) as the only viable means of restoring what can be restored. What will be required will be producing all the energy that put the carbon dioxide that put the CO₂ there in the first place plus energy to overcome the entropy of mixing, but with high exergy recovery, it seems feasible, with the economic advantage of providing carbon materials that play key roles in our lives but are still, as of yet, derived from fossil fuels.