WASHINGTON, DC, Apr. 17 -- Enhanced oil recovery is merely the first step in a national effort to capture and store or reuse industrially produced carbon dioxide, witnesses told the US Senate Energy and Natural Resources Committee on Apr. 16.
The CO2 already used for EOR in the US is dwarfed by future requirements, said Thomas D. Shope, acting assistant secretary for fossil energy at the US Department of Energy. But US Geological Survey Director Mark D. Myers said such applications in oil and gas fields could supply important information about other carbon storage applications.
Myers said, "Outside the traditional oil and gas reservoirs, there's very little data. Obtaining it will require a collaborative effort with states and other entities."
Another federal government witness on a second panel said the US already has extensive carbon sequestration experience from its enhanced recovery applications so far. "Power plant-scale volumes of CO2 have been handled, transported, and injected into geologic reservoirs for more than 30 years as part of EOR operations in the Permian basin of West Texas," said George Guthrie, fossil energy and development programs director at the Los Alamos National Laboratory (LANL) in New Mexico.
Analog sites can provide information on long-term concerns such as the fate and impact of CO2 storage, Guthrie said. "Wellbores are an excellent example. They are a critical component of the containment system. They are used to place the buoyant CO2 below an impermeable barrier. The problem is that wellbores use cement which may degrade when exposed to CO2 and water," he said.
As part of the LANL's support of DOE's carbon sequestration program, Guthrie said the laboratory recently completed the first field-based study of this issue using samples from a mature EOR site.
"The results show that interactions do occur, but complete degradation may not be an issue for some geologic environments," Guthrie said. "In fact, in some cases, beneficial reactions may actually improve the integrity of the wellbore. We need more studies, but these results demonstrate the importance of field observations in developing a reliable risk framework."
A major question that emerged during the hearing was whether to fund pilot projects using available technologies and information or identify future storage locations and carbon capture, transmission, and storage techniques. Another involved liability and whether treating industrially produced CO2 as a waste would limit its reuse beyond EOR.
DOE's Shope said the department's regional carbon sequestration partnerships have identified potential Canadian and US sites where more than 3,500 billion tons of CO2 might be stored. But Myers of USGS said more rigorous research, with a full scientific peer review, is needed. He said it would take a year to develop the methodology, another year to conduct the peer review, and 2-3 additional years to complete.
That led committee member Craig Thomas (R-Wyo.) to observe: "Sometimes, we get so taken up with research that we don't move forward with information we already have."
Chairman Jeff Bingaman (D-NM) called the hearing to discuss two bills before the committee. S. 731 would request the Interior secretary to oversee a USGS study that would develop a methodology for, and completion of, a national assessment of geological storage capacity for CO2. S. 962 would amend the 2005 Energy Policy Act to reauthorize and improve DOE's carbon capture and storage research, development, and demonstration program.
Bingaman said, "It's my purpose, and the purpose of this committee, to move forward as aggressively as possible to see how extensively sequestration can be used to handle CO2 which is produced."
Shope and Myers said while the administration of President George W. Bush supports the bills' goals, the measures must compete with others for federal funding. Myers said while S. 731, the CO2 storage capacity assessment bill, would supply critical information, "we cannot commit to meeting the time frames it establishes."
Shope said the $86 million requested by DOE will fully support its carbon sequestration program for fiscal 2008. "You need to develop the capture and transmission technologies along with storage," he said, adding that initial applications could occur around 2025 with full-scale commercialization taking place 20 years later.
David G. Hawkins, climate center director at the Natural Resources Defense Council, said this should happen sooner. "We do not need to delay large-scale demonstrations for a national data base but can move ahead with them now," he said. Early efforts should be focused on actual carbon capture techniques, he added.
Shope said while future US carbon sequestration volumes are significantly greater than the amount used for EOR, "the oil and gas industry is considerably more experienced in this matter than utilities."
But Myers said while CO2 injection for EOR is understood, its behavior in saline and other formations is not. "You may not know what the geologic downdip of the reservoir is so you don't know the capacity. You also don't know how long you will need to store it," he said.
Guthrie concluded: "We are at a point where many of the remaining questions can only be answered by larger field efforts. We know we can handle and inject CO2 safely at large volumes. But we need to show that CO2 capture at power plants works. We need to improve our estimates on the overall capacity for geologic storage. And we need to develop the confidence that CO2 storage is a safe and effective option for the long-term."
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