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Comment by mempko | Hacker News Reader

Regarding carbon capture, it will take more energy to capture the carbon than we burned putting it up there in the first place. Alan Kay, who actually did some systems work on the environment, explained it to me that the climate system is like an upside down coke bottle. It doesn't take much energy to tip it over, but it takes a lot more to put it back up.

In other words, we shouldn't have tipped it over in the first place. We may not have the energy to put things back to a habitable place.

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Physically that’s not the case.

Scaled up nuclear power could be had for $3-4B a gigawatt/h. We waste say $1T a year on basic things, like not having universal healthcare. So a simple policy change would let us build about 300 reactors a years, after some scaling period. The excess energy can be used to turn C02 back into oil.

It’s not technically that difficult, we just chose to waste money on stupid things and rich people toys instead.

Energy abundance is simply the choose to build nuclear power plants at scale

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."

This is simply saying “current tech doesn’t allow for this”. True. However there are potential avenues That will greatly increase the efficiency, and there are many companies pursuing these avenues so I don’t expect current tech to remain such forever.

The fact that you are thinking at the company level instead of an international world wide Manhattan project level should suggest how much you might not grasp the scale of the problem.

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