Scientists believe they have found a clever way to reduce carbon dioxide emissions – only turning them into stone. Researchers reported an experiment in Iceland that injected carbon dioxide and water within volcanic rocks. Reactions with minerals in the deep layers of basalt converted carbon dioxide into a stable solid, chalk consistency. Another encouraging result, as described the group in an article in the journal Science, was the process speed: a matter of months.
“Of 220 tons of injected carbon dioxide, 95% was converted into limestone in less than two years,” says the research coordinator, Juerg Matter, University of Southampton, UK. “It was a great surprise to all scientists involved in the project, and thought: ‘Wow, that’s really fast,” said Matter in an interview with radio program Science In Action (Science in Action), the BBC.
With the increase of carbon dioxide concentration in the atmosphere and the consequent warming, researchers are eager to investigate the so-called solutions of carbon capture and storage. Previous experiments injected pure carbon dioxide into sandstone, or deep aquifers with salt water.
The chosen locations – which included disabled wells of oil and gas – is worth impermeable layers of hard rock to contain carbon dioxide. But the fear was that the gas always find a way to return to the atmosphere.
The so-called Carbfix Project in Iceland, on the other hand, seeks to solidify the unwanted carbon. The researchers also “marked” CO2 with carbon-14, a radioactive form of the element. In this way they could verify that part of the injected CO2 was returning to the surface or flowing for some watercourse. No leakage was detected.
“This means we can pump large amounts of CO2 and store it well safely and in a short period of time,” said study co-author Martin Stute, the Earth Observatory Lamont-Doherty, Columbia University, USA .
Geothermal plant Hellisheidi now progressed beyond the experiment described in Science, and is routinely injecting CO2 underground, and in large volumes. The company is also buried hydrogen sulfide – another byproduct of the plant. This helps residents who have had to live with any rotten egg smell invading their properties.