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Can we sweep our CO2 emissions under the rug?

Carboneo, the start-up recycling CO2 into fuel

Cécile Michaut, Science journalist
On May 26th, 2021 |
2 min reading time
Marc Robert
Marc Robert
Professor at Université de Paris and Head of the Laboratory of Molecular Electrochemistry (CNRS)
Key takeaways
  • French start-up, Carboneo, is seeking to transform atmospheric CO2 into oxygen and carbon monoxide (CO) - a very useful molecule for the chemical industry.
  • To do so, Carboneo wants to capture CO2 from industrial sites (cement/steel factories or the chemical industry) the emissions from which, in France, were calculated at 133 million tons in 2019.
  • The technology developed by Carboneo has several advantages: it does not contain any rare metals whilst operating at ambient temperature and pressure.
  • The proof-of-concept was published  in the journal Science in 2019 and the challenge now is to increase scale.

Recy­cling CO2 instead of emit­ting it into our atmos­phere is one of the pos­si­ble solu­tions to reduce our green­house gas emis­sions. But we need proof that this tech­nol­o­gy is indus­tri­al­ly viable.

What if it was pos­si­ble to recy­cle CO2? This is the inno­v­a­tive idea sought out by sev­er­al researchers and start-ups around the world, includ­ing the French com­pa­ny Car­bo­neo, cre­at­ed in Decem­ber 2020. Their objec­tive: to trans­form CO2 into CO (car­bon monox­ide) and oxy­gen. Car­bon monox­ide is a very use­ful mol­e­cule for the chem­i­cal indus­try, it could serve as a build­ing block for new prod­ucts or fuel.

An indus­tri­al pilot as ear­ly as 2025

The idea is to cap­ture CO2 where it is con­cen­trat­ed, mean­ing on indus­tri­al sites such as cement or steel fac­to­ries, or the chem­i­cal indus­try, and then to pro­duce car­bon monox­ide. After­wards, the CO can be rein­ject­ed into the indus­tri­al process or sold. The tech­ni­cal pro­ce­dure is per­formed elec­trolyt­i­cal­ly (unlike a bat­tery) and there­fore con­sumes elec­tric­i­ty. On one of the elec­trodes, the CO2 is reduced to CO, while on the oth­er, water is oxi­dised to form oxygen.

Even though the con­cept is appeal­ing, it will not be indus­tri­al­ly viable right away. The proof-of-con­cept was pro­vid­ed in 2019 via an arti­cle in the jour­nal Sci­ence1 pub­lished with Cana­di­an researchers, but the chal­lenge is now to upscale. With this goal in mind, Car­bo­neo is join­ing the busi­ness incu­ba­tor Acce­lair of Air Liq­uide, at Jouy-en-Josas (Yve­lines, France). “Lab­o­ra­to­ry and medi­um-sized pilots are under devel­op­ment, and we plan to build an indus­tri­al pilot in 2025”, says Marc Robert, pro­fes­sor at the mol­e­c­u­lar elec­tro­chem­istry lab­o­ra­to­ry of the Uni­ver­sité de Paris (CNRS), and co-founder of Carboneo.

No rare metals

The advan­tage of the tech­nol­o­gy devel­oped by Car­bo­neo is its sim­plic­i­ty: the cat­a­lyst does not con­tain any rare met­als, only abun­dant ele­ments like iron, cobalt and car­bon. The elec­trol­yser oper­ates at ambi­ent tem­per­a­ture and pres­sure, and the elec­trolyte is water, which avoids pol­lu­tion. Final­ly, form­ing the elec­trode is sim­ple: the cat­a­lyst, mixed with car­bon ink, is deposit­ed on a paper-based elec­trode, which is dis­persed when the ink evaporates.

The dif­fer­ent pilots will have to show that the elec­trol­yser also works at a larg­er scale, can remain sta­ble for long peri­ods , and that costs and main­te­nance are man­aged. It is a dif­fi­cult task, because for the moment they only know how to trans­form a few mil­ligrams of CO2 per hour. Where­as the objec­tive is to reach a few dozen kilo­grams per hour in the pre-indus­tri­al pilot.

What ener­gy and finan­cial cost?

Nonethe­less, recy­cling of CO2 is not a mir­a­cle solu­tion. We can­not toss aside efforts to reduce CO2 emis­sions. To give a sense of scale, CO2 emis­sions due to indus­try (includ­ing the man­u­fac­tur­ing indus­try, ener­gy and waste pro­cess­ing) amount­ed to 133 mil­lion tons in 2019 in France2. But to recy­cle 1kg of CO2, you need between 4 and 7kWh of elec­tric­i­ty depend­ing on the per­for­mance of the elec­trol­y­sers. Recy­cling all the CO2 emit­ted by the French indus­try would con­sume between 532 and 931 ter­awatthours (TWh), which is more than total French elec­tric­i­ty pro­duc­tion for that same year (537,7TWh)!

That being said, all solu­tions must be con­sid­ered to reduce CO2 emis­sions in the atmos­phere. The main ques­tion will be the cost of this tech­nol­o­gy. “Today, CO2 costs almost noth­ing: 50€/kg at most. But the car­bon tax should triple by 2030, it will become expen­sive for indus­trypoints out Marc Robert. Will that make the recy­cling of CO2 cost effec­tive? The future of this tech­nol­o­gy will depend on poli­cies around the price of car­bon and emis­sion reduc­tion obligations.


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