Engineers and environmentalists around the world are keeping an eye on Decatur, Ill., where the Midwest Geological Sequestration Consortium (MGSC) has begun injecting dense-phase carbon dioxide into a porous rock layer more than a mile below the earth's surface. The methodology could provide a means for point sources of CO2 throughout the 60,000-sq-mile Illinois Basin, including more than 100 fossil-fuel-burning powerplants, to improve their environmental friendliness, given concerns about the contributions of CO2 emissions to global climate change.

But the project will take an even more interesting turn in a little more than a year, when crews complete a second injection well, just ¾ mile from the first, in the Mount Simon Sandstone layer that underlies much of Illinois, Indiana and Kentucky. Intensive subterranean and surface instrumentation will allow scientists to monitor the ways in which two injection streams interact in close proximity to one another, a significant accomplishment, given that carbon-storage projects may require several wells to capture the volume of CO2 produced by powerplants or other point sources.

"This will mark the first site in the world where we'll be able to follow the interaction of two plumes of CO2 injected in the same saline formation," says Robert Finley, principal geologist with the Illinois State Geological Survey (ISGS) and director of its Advanced Energy Technology Initiative.

ISGS is one of five consortium members involved in ongoing carbon capture and sequestration (CCS) efforts in Decatur; others include Schlumberger Carbon Services, which is consulting with ISGS on subsurface storage portions of the program, and Decatur-based Archer Daniels Midland Co. (ADM), which is supplying the CO2 and financing construction of the collection, compression and dehydration facilities required to sequester it. The U.S. Dept. of Energy's Office of Fossil Energy is providing additional funding and support for both projects.

Project team members are implementing the multiphase research and demonstration program at—and beneath—an ADM ethanol plant, where the CO2 originates. Having begun operations in November, the Illinois Basin-Decatur Project (IBDP) is injecting the CO2 at a nominal rate of 1,000 tons a day. The consortium's goal is to store 1 million tons by the end of 2014, when members will assess the feasibility, effectiveness and safety of the method. The second injection well, known as the Illinois Industrial Carbon Capture and Storage Project (IL-ICCS), broke ground in August 2011 and, once complete, will scale up the IBDP project to full industrial-level production.

When it assumes operations, the $207-million IL-ICCS will process and store three times more CO2 than IBDP, says Scott McDonald, ADM's biofuels development director and project manager for the IL-ICCS project. In addition to construction of a second well, plans call for expanding capacity at the collection, compression and dehydration facility with the addition of two 3,000-hp collection blowers; four 3,250-hp four-stage, six-cylinder reciprocating compressors; three 400-hp CO2 booster pumps; and a substation to supply power to the compression station.

Resulting capacity will accommodate an additional 2,000 metric tons of CO2 per day, an amount sufficient to boost total injection capacity on site to 3,000 mtpd, or about a quarter the amount a mid-size powerplant produces on a daily basis.

While ADM is performing all process engineering for the project, Schlumberger is overseeing seismic acquisition, data processing, reservoir modeling and well design and construction.