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Comment by koverda | Hacker News Reader

We can just store the fuel for carbon capture in that case, right?

Sure, but if carbon capture is the goal there are easier methods than artificial photosynthesis. The point of artificial photosynthesis is to create a fuel you can eventually burn again.

Re-using the CO2 in the atmosphere certainly beats simply adding to it, I'm guessing that's the point here.

For it to be truly sustainable the carbon needs to be stored in a way that humans wouldn't get at out of greed ever again. So it would need to be in some useless form like maybe diamonds or something.

A ton of CO2 is produced by about $150 worth of fuel (oil). So if you can do carbon capture for less than $150/tCO2 it would make more sense to sell the fuel and capture more carbon.

> So if you can do carbon capture for less than $150/tCO2 it would make more sense to sell the fuel and capture more carbon.

How does this math work?

If it's $149 to recapture, who's paying for this $149? Is the person buying $150 worth of fuel now paying for it also, at ($150 + recapture cost)/gallon?

I believe the idea is to sell captured carbon to be used as fuel. So we are net 0.

That would be valid once we stop extracting carbons from other sources (oil, gaz, coil…). Since that won’t happen at a global scale soon, burning the captured carbon won’t stop the carbonification of the air/water.

The $1 profit goes towards paying for capturing carbon. Every 150 barrels of captured fuel you sell, you make $75 profit you could spend on either not selling a barrel, or some more efficient way of reducing our climate impact like maybe buying a solar panel or sponsoring a windmill.

Or what the sibling suggests, you keep the money as profit / funds for growing the business so you displace traditional oil and you prevent the increase of CO2 in the atmosphere that way.

In terms of energy, you'll always need more to recapture than burning that fuel will give you (cuz entropy)

So if money = energy (which is a wrong assumption), buying that barrel would always be a loss

Unless that barrel is a higher value to you than the energy required to create the barrel would otherwise be.

If you capture the carbon for example as carbon dioxide instead of methane "cuz entropy" need not apply.

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