"Current leaders like Climeworks and Heirloom estimate they need ~2-3 megawatt-hours of energy to remove and compress a single tonne of CO2 for storage."
My calculation suggest that the absolute minimum energy required to separate CO2 at 400 ppm from air is around 136 MWh/tonne. My calculation is based on the entropy of mixing of CO2 with air and the associated Gibbs Free Energy.
Could you please explain to me how you come up wit your estimates? Thanks
There are a couple of papers referenced at the bottom of the post that outline the energy requirements of different approaches.
In your linked post, you identify 100GW of continuous power for the 1B tonne facility each year (above the calculated minimum of ~22.4GW of continuous power). If we take that 100GW as 100,000MW of continuous power for 8,760 hours per year, that would imply 876,000,000 MWh of power required for the 1B tonne facility, or 0.876 MWh per tonne. This is optimistic, but in the right ballpark.
Assuming the '8% efficiency' for Climeworks is in relation to the 22.4GW minimum you've calculated, then that would imply ~280GW of continuous power for a 1B Climeworks facility, or ~2.5MWh per tonne (right in the stated range of ~2-3MWh per tonne).
I don't see the 136 MWh / tonne in your linked post? Am I missing something?
Dear Sean, Good Afternoon.
At the head of your article you state that:
"Current leaders like Climeworks and Heirloom estimate they need ~2-3 megawatt-hours of energy to remove and compress a single tonne of CO2 for storage."
My calculation suggest that the absolute minimum energy required to separate CO2 at 400 ppm from air is around 136 MWh/tonne. My calculation is based on the entropy of mixing of CO2 with air and the associated Gibbs Free Energy.
Could you please explain to me how you come up wit your estimates? Thanks
Best wishes
Michael de Podesta
P.S. Here's an article I wrote on this recently.
https://protonsforbreakfast.wordpress.com/2025/03/02/direct-air-capture-of-one-billion-tonnes-of-carbon-dioxide-per-year/
Hi Michael, thanks for reading!
There are a couple of papers referenced at the bottom of the post that outline the energy requirements of different approaches.
In your linked post, you identify 100GW of continuous power for the 1B tonne facility each year (above the calculated minimum of ~22.4GW of continuous power). If we take that 100GW as 100,000MW of continuous power for 8,760 hours per year, that would imply 876,000,000 MWh of power required for the 1B tonne facility, or 0.876 MWh per tonne. This is optimistic, but in the right ballpark.
Assuming the '8% efficiency' for Climeworks is in relation to the 22.4GW minimum you've calculated, then that would imply ~280GW of continuous power for a 1B Climeworks facility, or ~2.5MWh per tonne (right in the stated range of ~2-3MWh per tonne).
I don't see the 136 MWh / tonne in your linked post? Am I missing something?