So many of the comments here talk about using abundant solar energy as a solution to the atmosphric CO2 problem. But unfortunately, solar energy isn't even close to providing the energy we need for home-heating, transport and industry.

We have to start from where we are: we can't just warp into a future where Dyson Spheres are realistic. We have less than thirty years. I suspect it's actually already too late. Using solar to reduce Gallium, so we can use the Gallium to reduce CO2, while we continue burning hydrocarbons because the solar is all being used to reduce Gallium (or solve hashes), doesn't look to me like the way forward.

> solar energy isn't even close to providing the energy we need for home-heating, transport and industry.

It provides more than enough energy for these things in some places at certain times, we can build the CO2 extractors in these locations

So use that energy directly. Why burn carbon, release CO2, capture the CO2, and use the sun to turn it back into carbon?

It could be far more efficient than using batteries. Not round trip total energy efficient, but moving around carbon based fuel, refueling vehicles, energy density and cost to produce and retrofit generators

> So use that energy directly

This would use that energy directly. To sequester carbon.

> why burn carbon

I didn’t say anything about burning carbon.

This tech can only sequester CO2 without the presence of O2. Where does CO2 occur without O2? In the exhaust of power plants/engines/heaters that burn hydrocarbons.

If you didn't say anything about burning carbon, you weren't paying attention.

> This tech can only sequester CO2 without the presence of O2. Where does CO2 occur without O2?

Here is a system for collecting CO2 from ambient air and discharging a stream of pure CO2:

https://news.mit.edu/2019/mit-engineers-develop-new-way-remo...

> If you didn't say anything about burning carbon, you weren't paying attention.

Wrong.

The creation of solar cells to capture that sun takes time, and rare earth elements which have to be extracted from the environment. To use solar to capture carbon, you'd have to make enough solar panels to replace all the fossil fuel sources, then more. That's not happening any time soon, it can't.