Now that it is running out, it is worth remembering the speech at the opening of COP26, in which Mario Draghi stated that “we must be aware that renewable energies can have limits”, inviting us to “invest in innovative technologies for carbon capture. “. In short, according to the Prime Minister, it is not enough to reduce the carbon intensity of the energy mix, it is also necessary to remove CO2 emissions. But how
There are several technologies to implement negative emissions. For example, by capturing carbon dioxide during a production process before its release into the environment and storing it underground. This technique is called carbon capture and storage, CCS. Or on it can suck the CO2 molecules directly from the air with special filters, which is then reintroduced without CO2 into the atmosphere: it is called direct air capture, DAC. Although technically tested, there are still few industrial-sized plants and costs remain high.
The decarbonisation process separates CO2 from the exhaust gases of refineries, steel mills, cement factories, foundries, chemical plants, waste-to-energy plants, etc. preventing it from being released into the air. Once compressed and liquefied, carbon dioxide can follow two paths. It is used industrially in water treatment, in the manufacture of fire extinguishers, plastics and fertilizers, in the food and pharmaceutical industries, in special welding or to produce blue hydrogen. Or it is injected underground with various procedures.
In the oil sector, gas captured and transported by pipeline or ship to its final storage location, generally former oil and gas fields, including offshore. In addition to becoming treasures of captured CO2, these disused oil fields are reactivated thanks to the thrust of hydrocarbons towards the well as a result of the emission of the captured carbon dioxide.
An alternative storage procedure is to transform CO2 into rock. Mixed with water, it is introduced deep into volcanic basalts containing minerals that interact with carbon dioxide to form, within a couple of years, calcium carbonate, the main component of limestone.
In September, the first industrial DAC plant near a geothermal power plant was inaugurated in Iceland, which supplies green energy to the intake of air in chemical filters that capture CO2 as the air passes through them. Subsequently heated, they release the CO2 again, generating a flow of gas to be stored underground. When fully operational, the plant absorbs 4,000 tons of CO2 emissions a year, (almost like taking 1,000 cars off the road) out of a world volume of about 35 billion tons of CO2. The cost of the procedure is around 600-800 dollars a ton, ten times the price of the ton on the carbon market. But the founders of Climeworks, a Swiss company that has also built a pilot plant in Troia in Puglia, are confident of the business prospects.
From Microsoft to the Swiss Re insurance group, the list of customers determined to capture the emissions of their business is growing. And as with solar panels, the cost of CO2 capture and storage will also follow a decreasing trajectory. But then why, in the name of technological neutrality, do not listen to Mario Draghi, stop considering the removal and storage of CO2 as a practice to be ignored

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