STONE COLD - CO2 to Rock

"To combat climate change, these scientists are turning CO₂ into rock" PBS NewsHour 8/23/2016

Excerpt

SUMMARY:  Carbon dioxide in the atmosphere is a major contributor to global warming.  But what if there were a way to turn that gas into rock and store it safely, thousands of feet underground?  One power plant in Iceland is attempting to do just that, through a process called “Carbfix.”  Special correspondent Malcolm Brabant reports, in the first of his “Breakthrough” series.

MALCOLM BRABANT, Special correspondent:  I'm standing about 1,000 feet up a volcano that last erupted about 2,000 years ago.  The temperature underground here is about 620 degrees Fahrenheit.  According to geologists, this volcano could blow at any time.  But that could be any time within the next 1,000 years.

The process of turning carbon dioxide into rock is happening about 6,000 feet below my feet silently.  But up here, you can really sense the visceral power of Mother Nature.  The only sensation I can compare it to is being rather close to the launch of a space shuttle.

WOMAN:  This is Hellisheidi geothermal power plant.  The thermal energy is transported towards Reykjavik, where we heat our houses and take showers and so forth.

EDDA ARADOTTIR, CarbFix Project Director:  So, as a byproduct of the ongoing energy production, geothermal gases like CO₂ are emitted to the atmosphere.  But we have been working towards reducing these emissions, capturing them and reinjecting them into the ground and turning them into rock.

MALCOLM BRABANT:  The techniques pioneered here are said to be safer than the alternative of storing CO₂ as a gas underground, with its expense and potential for leaks.

Under the right conditions, nature takes hundreds of years to transform CO₂ into stone.  What the scientists have done is to accelerate the process exponentially.

EDDA ARADOTTIR:  This represents methods that can be used for fighting global warming and climate change.  And to that respect, it's a powerful box.

So, this is calcium carbonate.  And this is what the CO₂ injected into the basalt turns into after the chemical reactions have occurred.  This one is not representative of what we would see if we were to drill a core or dig a hole into the bedrock where we are injecting the CO₂.  Rather, we would see something like this, where we have the calcium carbonate in smaller particles.