From: Roger Greenway, ENN
Published July 27, 2013 07:47 AM

CO2 Sequestration advances

Sequestration of CO2 has been discussed as one way to reduce the impact of burning fossil fuels on climate change by removing CO2 from industrial and power generation emissions and storing it indefinitely underground. This technology has been demonstrated in the laboratory and in pilot studies, but not in large scale tests. That is now changing.

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An injection of carbon dioxide, or CO2, has begun at a site in southeastern Washington to test deep geologic storage. Battelle researchers based at Pacific Northwest National Laboratory are injecting 1,000 tons of CO2 one-half mile underground to see if the greenhouse gas can be stored safely and permanently in ancient basalt flows.

Boise Inc. teamed with Battelle, which operates PNNL for the U.S. Department of Energy, and Praxair, Inc. to conduct the CO2 injection phase of the pilot project. Injection is occurring on Boise property in deep basalt — the same massive ancient lava flows that underlie major portions of Washington, Oregon and Idaho. The joint research is conducted under the Big Sky Carbon Sequestration Partnership, which is led by Montana State University and funded by DOE and a consortium of industrial partners. It is one of seven regional partnerships throughout the United States aimed at finding safe and economical ways to permanently store the nation's greenhouse gas emissions.

"We have been conducting laboratory tests on basalts from the region for several years that have conclusively demonstrated the unique geochemical nature of basalts to quickly react with CO2 and form carbonate minerals or solid rock, the safest and most permanent form for storage in the subsurface," said Battelle project manager Pete McGrail. "However convincing the laboratory data may be, proving the same processes operate deep underground can only be done by conducting a successful field demonstration. We have taken the very first steps to do that here in Wallula."

During the next two to three weeks, Battelle scientists will work with Praxair technicians to inject into porous layers of basalt CO2 that has been compressed into a liquid-like state. Thick and impermeable layers of rock above these porous layers will act as barriers or seals to prevent the CO2 from travelling vertically upward.

Over the next 14 months, fluid samples will be extracted from the injection well. Scientists will look for changes in chemical composition in comparison to baseline data compiled prior to injection. Scientists will also compare results to predictions made using PNNL's supercomputer. At the end of the monitoring period, rock samples will be taken from the well. They are expected to exhibit the formation of limestone crystals as a result of CO2 reacting with minerals in the basalt.

Smokestack image via Shutterstock.

Read more at Pacific Northwest National Laboratory.

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