Scientists Turn CO2 'Back Into Coal' In Breakthrough Experiment (independent.co.uk)

"Scientists have managed to turn CO2 from a gas back into solid 'coal'," reports The Independent, "in a breakthrough which could potentially help remove the greenhouse gas from the atmosphere." Long-time Slashdot reader bbsguru shared their report: The research team led by RMIT University in Melbourne, Australia, developed a new technique using a liquid metal electrolysis method which efficiently converts CO2 from a gas into solid particles of carbon. Published in the journal Nature Communications, the authors say their technology offers an alternative pathway for "safely and permanently" removing CO2 from the atmosphere....

RMIT researcher Dr Torben Daeneke said: "While we can't literally turn back time, turning carbon dioxide back into coal and burying it back in the ground is a bit like rewinding the emissions clock...." Lead author, Dr Dorna Esrafilzadeh said the carbon produced by the technique could also be used as an electrode.

"A side benefit of the process is that the carbon can hold electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles," she said. "The process also produces synthetic fuel as a by-product, which could also have industrial applications."
More coverage from Fast Company, Science magazine, and the CBC.

Comments

I wonder...

[Joce640k]

I wonder if it needs energy to do this, an amount of energy greater then the energy produced by burning it in the first place?

If so, why not just use that energy instead? Cut out the middle man.

Re:I wonder...

[bluegutang]

Yes, obviously the coal-CO2-coal cycle creates entropy, and thus is less efficient than just leaving the coal as coal and creating energy through some other method.

Perhaps there are places/times (like Iceland with its abundant hydropower, or wind-powered places when there is an excess of wind) where electricity is extremely cheap, and you could turn CO2-coal then, to make up for CO2 emissions at times when electricity is expensive. But this sounds like the world's least efficient kind of battery.

Re:I wonder...

[tomhath]

Of course it requires a lot of energy. Converting CO2 back to Carbon and Oxygen would only be sensible if you had excess power (no demand and no way to store it). It's unlikely there would ever be enough extra energy available to sequester a significant amount of Carbon, but if there's no better use for the free energy...

Re:I wonder...

[PPH]

Unless the efficiency is too low and the economics don't support it. Then we would be better off building battery banks and displacing future CO2 production with renewables. Existing CO2 can be removed from the atmosphere pretty quickly by photosynthesis.

Re: I wonder...

[ShanghaiBill]

Because just using the energy doesn't remove CO2 from the atmosphere.

Turning CO2 into coal requires more energy than we got by creating the CO2 in the first place. This makes little sense as long as we are still burning coal.

You don't need to reduce CO2 to carbon to sequester it. The CO2 can be compressed and injected into shale formations for a tenth of the energy. You can even make it cash-positive by using it for enhanced oilfield recovery.

Re: I wonder...

[Anonymous Coward]

The sun does shine and wind does blow 24/7 on our fine spheroid. Just not at every precise location all the time. The trick is to capture the energy and move it to load centers. Amazingly, this trick was solved on June 3, 1899 in Portland, Oregon with an invention called an Electric Transmission Line.

Re:I wonder...

[timeOday]

Institute a carbon tax, then pay out the negative of that for carbon sequestration, and then let it take its course.

Bury it in the ground ?

[religionofpeas]

Nobody's going to bury coal. If we can make coal from CO2, we're going to burn it.