Iceland: a power station has managed to turn CO2 into stone

One of the main human challenges for the coming years is to reduce greenhouse gas emissions because every year, tons of CO2 pollute the Earth’s atmosphere, accelerating global warming. But if, in addition to emitting less CO2, we manage to capture the one that is in very large quantities in the atmosphere? It is in a study published in the journal Science that Icelandic scientists claim to have developed a technique to achieve this by using basalt. Their method is to store carbon dioxide under the ground, in the form of rock. Solidify CO2, mixed with other gases and boiling water heated by geothermal energy, by injecting it into basaltic soils at 540 meters depth.

For several years now, teams of scientists have been working on CO2 storage technologies in the soil, nicknamed CCS (for “Capture and Storage of Carbon”). Until now, however, they were often considered dangerous because the gas could escape into the atmosphere.

Turning CO2 into stone

This time, the solution seems much more convincing. Initiated in 2012 at Hellisheidi’s Icelandic geothermal power plant (the largest in the world), the Carbfix project could well be the first to make the idea of ​​storing CO2 in the basement of the planet viable. The main reason for this success, the choice of volcanic basalt, which is particularly rich in calcium, iron and magnesium, three elements necessary for good solidification of carbon.

Turning CO2 into stone

A method that is therefore more safe, faster and cheaper than previous ideas regarding the storage of carbon dioxide in the form of gas. Indeed, in Hellisheidi, it took only a little less than two years for 95% of the infected CO2 to solidify, which means that only 5% evaporated into the atmosphere . This was surprisingly quick, since it was considered that it took several hundred or even thousands of years before carbon dioxide solidification took place. “What’s at work here is an accelerated natural process,” said geophysicist David Goldberg in The Independent magazine .

However, this method is exceptional because it is terribly expensive, and it consumes a lot of energy. Indeed, the Carbfix project will have cost $ 10 million, or 8.9 million euros. And then, operating at full speed, the turbines of the plant bring up various volcanic gases, including CO2 and hydrogen sulphide.

Turning CO2 into stone

It remains complicated to imagine that this method of solidification of carbon can be generalized in the world. However, Juerg Matter, a hydrologist at Columbia University and co-author of the study, believes that political inaction remains the real danger, astonishing not to see the proliferation of projects similar to Carbfix .

Pleasant prospects at a time when the climatic situation of the planet is ever more pressing. Projects of this type have been announced in other countries such as Canada. For its part, Iceland has announced a new target for Carbfix which should be able to store 10,000 tonnes of CO2 in the soil of the country per year.

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