CO2 capture, an asset to achieve our climate goals

«Le CO storage₂, it’s good. Sobriety is even better. » This is what Pierre Toulhoat told us, retired from his position as scientific director of the Bureau of Geological and Mining Research (BRGM) and member of the Academy of Technologies, more than a year ago. As he deciphered for us the challenges of what the experts call CCS – for capture and geological storage carbon.

He specifically addressed the storage stage. His speciality. And today, it’s Florence Delprat-Jannaud, head of the CSC program atIFP Energies nouvelles (IFPEN), which confirms this. “CCS technologies must in no way distract us from the essentials: efficiency and sobriety. » With it, we will more specifically address the issue of capturing carbon dioxide (CO₂). Her specialty.

Why ? Firstly because at the start of 2022, the Intergovernmental Group of Experts on the Evolution of the climate (IPCC) relaunched the urgency of deploying these technologies. Announcing that we were no longer in a position to do without it, if we still hope limit global warming at 1.5°C. Then because some Tech giants have just launched the Frontier initiative, a market guarantee that aims to accelerate the development of carbon capture technologies by guaranteeing future demand for them.

“There are already technologies that work well”, assures us Florence Delprat-Jannaud. She mainly wants to talk about solutions that capture CO₂ in factory fumes. Those of heavy industry, which does not currently have alternative technologies to reduce its carbon footprint.

CO capture technologies₂ already exist

“Capture of “post-combustion” fumes consists of recovering the CO₂ by washing these fumes with a solvent », explains the head of the CCS program at IFPEN. These technologies have been used for a long time to treat gas fossil and have been adapted to capture CO₂ industrial fumes. The problem is that they are expensive and consume a lot of energy. But the project “3D” which has just entered its phase « demonstrator industrial » could change that. And help decarbonize industries high CO emitters₂. Thanks to a solvent selected for its efficiency, its competitiveness, its sustainability and the energy savings it should make possible. A first industrial unit could be operational on the production site ofsteel of AcelorMittal, in Dunkirk, from 2025. With the aim of capturing more than one million tonnes of CO₂ every year.

Other CO capture solutions₂ existing systems, one can cite precombustion capture. The idea is to directly produce a combustible of carbon. An idea that only applies to a few industries. “And that should be considered at the time of the construction From the factory “, explains Florence Delprat-Jannaud. CO capture₂ can also be done by oxycombustion. “To increase the concentration of CO₂ in the fumes and thus facilitate its capture, we carry out a combustion in pure oxygen and no longer inair. But again, producing pure oxygen is expensive. »

“We are also working on more innovative processes, such as chemical loop combustion. It could hit the market by 2028”, explains Florence Delprat-Jannaud. On the other hand, the CO capture technologies₂ straight into theatmosphere, they are not ready on a large scale. From concentrations of around 10% – that’s already low -, we go to concentrations of around 0.04% – that’s tiny, even if it’s still far too much from a greenhouse effect point of view . This makes the capture operation much more delicate. However, around fifteen projects have been launched around the world. “But capturing CO₂ in the air is absolutely not economically viable today. »

Costs still high, but just waiting to come down

That’s to say ? “Capturing CO₂ in factory fumes, it now costs between 50 and 180 euros per ton, depending on the situation. The capture stage accounts for 50 to 70% of this amount. Compression and transport, each for 10%. The rest goes to storage”explains Florence Delprat-Jannaud. “But for direct capture in the atmosphere, it’s something else entirely. We are talking about costs between 300 and 800 euros per ton of CO₂ picked up. »

Costs which should generally decrease when the volumes treated will increase. With the evolution of technologies, too. According to IFPEN’s CCS program manager, “there is not a minute to lose. We must work to develop different capture solutions. And in parallel, we must also study the storage possibilities for this CO₂. »

Because there is doubt about it? “There is no doubt about the extent of underground storage possibilities. In Europe, the capacity is of the order of 500 gigatonnes, which is equivalent to a hundred years of emission – on the basis of the emissions of 2019 », tells us Florence Delprat-Jannaud. But each of the potential reservoirs will have to go through a fairly precise characterization stage before being used, in order to know exactly what volume it can receive. Or to check his sealing. And to develop long-term monitoring technologies. “For old tanks ofhydrocarbons, it takes a few years. But for saline aquifers which have not yet been explored by the oil industry, it takes about ten years. »

What should be remembered is therefore that if research still has work to do, there are already technologies for capturing CO₂ mature ones that could help us decarbonize industry above all. By 2070, the International Energy Agency estimates that CCS will offset the emission of 9.5 billion tonnes of CO₂. Enough to contribute 15% to the effort needed to save our climate. But for that, “We must act today. Implement CCS solutions in heavy industry, in particular. And start limiting what experts call incompressible emissions. To support the efforts of reduction of greenhouse gas emissions which must, moreover, continue to be granted”concludes for us Florence Delprat-Jannaud.