The energy transition requires carbon capture and storage processes (CSC) are returning to public debate. Elon Musk even pledged $ 100 million in January who would develop the best technology. Applied to industrial processes that emit CO2, technologies of CSC consist of separating and then capturing the file CO2 emitted before, during or after the combustion of fossil energy, and then compress it CO2 and store it deep underground. Storage locations are depleted oil or gas wells or other natural geological reservoirs that are presumed to be narrow (deep saline aquifers, non-exploitable coal deposits), to which the CO2 it is transported via pipelines.
The volumes involved by CSC they are very impressive. Imagine a large coal-fired power station like the one in Cordemais in the Loire-Atlantique. Its power is 1,200 MW (megawatts). When running at full capacity, it swallows about 12,000 tons of coal per day. Coal arrives in Cordemais by boat. But, to give an idea of what this volume represents, let’s say that, to transport these 12,000 tons in wagons of one hundred tons each, it would take a two-kilometer-long train pulled by two or three huge locomotives. Such trains do not exist in Europe.
We no longer have to transport 39,600 tons of carbon dioxide, but almost 48,000 tons
Let’s assume this coal is a good anthracite with a carbon content of 90 %. By the end of the day we will have burned 10,800 tons of carbon (90 % of 12,000 tons). Burning in the air, each carbon atom combines with two oxygen atoms to produce a carbon dioxide molecule (this is why carbon dioxide is written CO2). But oxygen atoms are a third heavier than carbon atoms. A carbon atom combined with two oxygen atoms to form a molecule of CO2 it weighs 3.66 times the weight of the newly burned carbon atom. And so, when 10,800 tons of coal has been burned, the carbon capture and storage process must go back into a giant hole, 39,600 tons of compressed carbon dioxide.
Make the file CSC, from the extraction of carbon dioxide from the fumes of coal-fired plants to its burial, through its compression and transport, consumes energy in itself, in the order of 20 % of consumption to which it applies. The implementation of CSC on a coal plant therefore implies that it is necessary to transport no longer 39,600 tons of carbon dioxide, but almost 48,000 tons, or the content of four trains like the one we have mentioned !
Note that the process does not remove anything from other carbon pollutants (mercury, arsenic, lead, cadmium, antimony, thorium and other radioactive elements, ash and dust, and not only during extraction but during extraction). Use in power plants).
Then there are the problems of cost, operational reliability, losses during transport and leaks from geological storage tanks.
The CCS brings a huge advantage … to oil companies
One of the main problems concerns the control of the actors in CSC. History has repeatedly shown us the relative honesty of some industrial players and, as far as carbon is concerned, the manipulation of the carbon quota market by organized crime. For example, how can you be sure that a gas vessel carrying 100,000 tons of CO2 it will arrive at its destination when it is so easy to open the taps and degas in the open sea ? In this case, no oil spills, no toxic products, no odors, no tastes, no traces, no consequences. With a pipeline it would be even easier.
But, in fact, the CSC brings a huge advantage … to oil companies. The carbon dioxide injected into the old oil wells allows the oil that remains to rise up by increasing the pressure in the reservoir or by fluidization. Of the twenty-four experiments of CSC in operation around the world, nineteen sell the CO2 or use it directly for better oil extraction (in English EOR for better oil recovery). In Weyburn, for example, in Canada, the CSC extended the life of the oil field by a good twenty years and significantly increased the total amount of oil extracted, a “ formidable success story green “, titled in June 2020 The media JWN dedicated to the mining and oil industry.
Presented as a means to combat global warming, but at what incredible price, as we have seen, the CCS it could, in fact, extend the life of oil fields and thus stimulate climate change.
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