Comment by mempko

Since the industrial revolution we've emitted about 1.5 trillion tonnes of CO2. Direct air capture requires roughly 1,500 kWh per tonne, so recapturing all of it would take around 2,250,000 TWh. Current global electricity production is about 30,000 TWh/year. That's 75 years of the entire world's electricity output just for capture, before you even convert it back to fuel, which costs even more energy. And thermodynamically you can never break even: we only extracted maybe 30-40% of fossil fuel energy as useful work, but reversing the dispersal of CO2 from 420ppm in the atmosphere fights entropy all the way back. It will always cost more energy to put back than we got taking it out. As for the nuclear numbers: Vogtle, the only recent US build, came in at ~$16B/GW, not $3-4B. The world started construction on 9 reactors total in 2024. The all time peak was ~30/year in the 1980s. 300/year has never been close to reality. Average build time is about 9 years per reactor. I'm not anti-nuclear but you can't hand-wave your way past thermodynamics and industrial scaling with "it's just a policy choice."