Putting carbon back where it came from

Carbon is released when we burn fossil fuels—fuels that began as plants extracting carbon dioxide from the air.

It’s called the Carbon Cycle. Plants thrive on carbon dioxide and sunlight. As they die and return to the earth from which they grew, the extracted carbon remains. Over millions of years the stored carbon becomes coal, oil and natural gas.

Now, man is releasing that stored carbon back to where it started, the atmosphere, wrapping the Earth in a warming blanket and choking the seas that attempt to store it.

Scientists looking for a way to return atmospheric carbon to the earth for storage have turned carbon dioxide into stone in a matter of months by pumping it deep underground, offering a revolutionary new way of storing the greenhouse gas to tackle climate change.

The pioneering experiment in Iceland mixed CO2 emissions with water and pumped it hundreds of meters (feet) underground into volcanic basalt rock — where it rapidly turned into a solid.

“We need to deal with rising carbon emissions. This is the ultimate permanent storage — turn them back to stone,” said Juerg Matter, lead author of the study, which was published Thursday in the journal Science.

Carbon dioxide is a key factor in global warming, and experts have long called for innovative “carbon capture and storage” (CCS) solutions.
Previous attempts to inject CO2 into sandstone soils or deep saline aquifers have struggled, as they relied on capping rocks to hold the gas down — triggering fears it could eventually leak.

In contrast, the CarbFix project at Iceland’s Hellisheidi plant — the world’s largest geothermal facility, which powers Reykjavik — sought to solidify the CO2.

The plant produces 40,000 tons of CO2 a year — just five per cent of the emissions of a similarly sized coal plant, but still significant. In 2012, they began pumping 250 tons of CO2 mixed with water underground.

Scientists had feared it could take hundreds or even thousands of years for the mildly acidic liquid to solidify.

But 95 per cent of the injected mixture — which they had tagged with tracer chemicals in order to check it didn’t leak out — had became chalky white stone within two years.

“It was a very welcome surprise,” said Edda Aradottir, who heads the project for Reykjavik Energy.

Encouraged by the success, the company has scaled up the project and from this summer will be burying some 10,000 tons of CO2 each year, Aradottir said.

1 Comment

  1. Soundmind

    This is a much better idea than what is known as CO2 sequestration. In that process CO2 would be trapped as a gas underground. The problem is that not only is the capacity to do that limited but when it inevitably escapes it will kill everything around it for many miles. CO2 is called an asphyxiant (so is nitrogen.) It’s believed that an entire village in Africa was wiped out when CO2 trapped under rocks in a nearby lake escaped. But desperate people will try anything no matter how stupid or impractical.

    The good news is that it seems the process of CO2 bonding to rock at high temperature works. This should not come as a surprise to chemists. The bad news is that you have to get deep enough into the ground to get to sufficiently heated rock. In places like Iceland and Yellowstone Park that’s easy, it’s close to the surface. Other places you have to go much deeper. The bad news is that scaling up the process and deploying it to the extent it will have an impact will probably take decades. There’s the rub. By the time it is used to where it could make a difference, it will be too late to matter. The operation was a success but the patient died.

    And they still don’t talk about the root cause of global warming, overpopulation. It is taboo. Even China now encourages couples to have more children as its ill conceived one child policy resulted in an aging population and a gender imbalance.

    Is there an alternative? Yes, depopulation. Many advanced nations such as Italy, Japan, Russia have decreasing populations. The four horsemen of the apocalypse can help too. Famine, non nuclear war, outbreaks of incurable highly communicable disease, and the bankruptcy of Europe, China, the BRICs, and other places will mean some will die so others can live. The air and water pollution in places like China and India will probably kill off a lot of their populations. We didn’t clean up the environment in the US, we just exported the pollution along with our dirty industries. China is expected to run out of water by 2030. Gruesome to think that death can save life. Maybe that’s why it’s taboo. Arabia, how about a barrel of water for a barrel of oil? The nature and scale of our present technology given the size of our population and the capacity of the planet to absorb human waste products and still support human life is unsustainable. One way or another change is coming. Don’t expect China to cut back on burning coal or Indonesia and Brazil to stop destroying the rain forests. They say advanced nations like the US created the problem when they became prosperous, now it’s their turn.

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