Tackling disposal of greenhouse gas emissions
Feb. 6, 2006
KALAMAZOO--As evidence of global warming mounts across the globe, researchers at Western Michigan University are investigating a new way to stem its spread-- a way that could end up making a lot of money for the state of Michigan.
It's called geological carbon sequestration, a process that essentially liquefies carbon dioxide and disposes it thousands of feet beneath the ground. With the help of grants from the U.S. Department of Energy, researchers at WMU's Core Research Laboratory are investigating the feasibility of burying the harmless gas in the billions of cubic feet of porous rock that lie deep beneath Michigan's farm fields and forests.
Odorless and tasteless, carbon dioxide poses no direct health risk to humans and is used by plants in photosynthesis. But most scientists agree that the gas is wreaking havoc on the world's climate. When released into the atmosphere in massive quantities, mainly through the burning of fossil fuels, carbon dioxide molecules deflect solar radiation back to the earth, resulting in a gradual, but steady warming of the atmosphere.
Most of the world's industrialized nations have agreed to limits on greenhouse gas emissions. So far, the Bush administration has declined to sign on to the limits, known as the Kyoto Protocol. But many government officials and scientists recognize that it's only a matter of time before the United States, the No. 1 producer of greenhouse gases, has to take decisive action to limit emissions.
And that's where geological carbon sequestration comes in.
"The state of Michigan possess a substantial volume of underground void space," says Dr. David Barnes, the WMU associate professor of geosciences who is leading the research effort. "This huge volume of sub-surface space provides a potential repository for waste materials. This is a real economic opportunity for the state of Michigan."
States like Michigan with huge underground reserves of porous rock could become sites for large, modern power plants, where CO2 is captured, liquefied and pumped into the ground, Barnes says. The state would benefit from the jobs that would be created and the additional tax revenue.
WMU began the first phase of its CO2 sequestration research project in mid-2004 with the first of two grants from the Department of Energy. The first phase, funded by a $100,000 grant, ran through mid-2005 and was followed by a second DOE grant for $280,000 to begin a second phase. Michigan is part of the DOE's Midwest region carbon dioxide sequestration program. Barnes is being assisted in WMU's project by co-investigators Dr. G. Michael Grammer, WMU associate professor of geosciences, and Dr. William B. Harrison, WMU professor emeritus of geosciences and Core Research Laboratory director.
The project is assessing the feasibility of capturing CO2 from large-scale emitters, such as ethanol plants, cement factories and, in particular, coal-fired power plants, compressing the CO2 into a dense, fluid-like state, then injecting it deep into the ground. The porous rock strata to be used are far deeper than any fresh water aquifers used for drinking water to eliminate any threat to fresh water quality.
The volume of CO2 being emitted into the atmosphere is in the billions of tons annually, Barnes says. But even at current levels, researchers estimate there is enough porous rock in the Midwest region to store CO2 from large-source emitters for some 600 years. Pumping it deep into the ground also will maintain the pressure needed to keep the CO2 in a liquid form.
Researchers have proposed a pilot project in an area of natural gas well fields in northern lower Michigan. The natural gas being extracted there is high in CO2 and, as it is processed, the CO2 is being vented into the atmosphere. The plan is to capture the CO2, pressurize it and pump it into the ground. The project will take some three or four years to complete, in part because researchers want to be sure that the gas remains pressurized and does not escape back into the atmosphere.
CO2 sequestration can have a secondary benefit by enhancing oil recovery, Barnes says. In places where oil has been extracted and production through natural pressure drive is depleted, CO2 could be pumped into the field and used to force additional oil from the ground. In fact, an oil producer in northern Michigan is doing just that.
WMU is part of one of 14 consortia in the nation studying various aspects of carbon sequestration. The Midwest region is being overseen by Battelle, a global science and technology company headquartered in Columbus, Ohio, that develops and commercializes new technology. Battelle has been awarded $14 million by the Department of Energy to investigate CO2 sequestration and has contracted with U.S. State Geologic Surveys in six states and WMU to carry out studies in the Midwest.
If CO2 emissions become regulated, which seems likely, companies would be interested in building new power plants located where the gas can be cheaply and easily disposed of on site. Michigan, with its vast reserves of porous rock, would provide an ideal place for such modernized plants.
Michigan ranks 13th among oil and natural gas producing states in the nation, Barnes says. The states ranking above Michigan probably would have more porous rock, but it's also a matter of which area best serves the power requirements of a given region. A power plant in Michigan could serve many large metropolitan areas nearby.
The environmental community has been somewhat unenthusiastic about the idea, Barnes admits. But the gas would be pumped to depths ranging from about 2,500 feet to as much as 10,000 feet beneath the surface and would pose no threat to wells used for drinking water.
Barnes says geological carbon sequestration offers the potential for an economically viable, near-term alternative to venting CO2 into the atmosphere from large point sources.
"Geological carbon sequestration should be considered as only one technology in a suite of technologies that we must develop to address environmental concerns over CO2 emissions," Barnes says. "Maintaining our capability to provide relatively inexpensive power is a critical component to security and stability in modern industrialized societies and is especially important during the inevitable transition period to alternative methods for industrial scale power generation."
Media contact: Mark Schwerin, (269) 387-8400, firstname.lastname@example.org