Basalt—A Better Sequester?
Scientists Attempt to Permanently Trap Carbon Dioxide in Deep Basalt

Laboratory studies by researchers at the Battelle-operated Pacific Northwest National Laboratory (PNNL) indicate basalt formations may quickly and effectively sequester carbon dioxide (CO2), the predominant gas implicated in global warming.

Researchers hope to test their findings when they inject 3,000 tons of carbon dioxide—approximately the amount of CO2 that a 150-megawatt, coal-fired power plant emits daily—3,000 feet into Washington State’s Columbia River basalt formation. Their goal is to determine if the massive lava layers can permanently store the CO2.

“If the process is viable, we think basalts in the Pacific Northwest could sequester more than a century’s worth of the CO2 generated in the region and create a major opportunity for zero-emission power generation in the Northwest,” said Dr. Pete McGrail, project manager.

This stratigraphic map (above) shows the layers of basalt beneath the injection site. The large zone of interest (middle pink) is located about 1,000 meters below the ground surface. The project will utilize six preexisting monitoring wells within 100 meters of the injection site to provide detailed information about the vertical migration of the carbon dioxide plume.

“Experimental data from our laboratory studies show that carbon dioxide injected into the volcanic rock should begin interacting with the minerals in the basalt to form calcite, which is the primary carbonate mineral in limestone, in four to six weeks,” McGrail said. “This carbonate mineralization will permanently and safely sequester the CO2 within the basalt formation —if it works in the field like it has in the laboratory.”

To help determine how much of the injected CO2 has been mineralized, McGrail’s team plans to drill down at an angle to the injection shaft and retrieve core samples 6 to 8 months and then 18 months after injection. Using a variety of geophysical monitoring methods, they also plan to track movement of the CO2 underground. They will use the experimental data to forecast the timing and extent of the sequestration in basalts.

McGrail points out that the CO2 injection will occur only after the site north of Richland, Washington, has been prepared and the necessary permits have been obtained.

The work was enabled through a U.S. Department of Energy award to the Big Sky Regional Carbon Partnership. The Partnership, led by Montana State University, includes a host of universities, national laboratories (such as PNNL), international research institutes, and private companies as partners. The project is part of the President’s Global Climate Change Initiative designed to reduce the nation’s greenhouse gas emissions intensity 18 percent by 2012.

For additional information, contact Dr. Pete McGrail at (509) 376-9193, pete.mcgrail@pnl.gov.