Geoscience Reference
In-Depth Information
The Carbon Sequestration Atlas was compiled from estimates of
geological storage capacity made by seven separate regional partnerships
(government-industry collaborations fostered by DOE) that each produced
estimates for different regions of the United States and parts of Canada.
According to DOE, geographical differences in fossil fuel use and
sequestration potential across the country led to a regional approach to
assessing CO
2
sequestration potential.
32
The Carbon Sequestration Atlas
reflects some of the regional differences; for example, not all of the regional
partnerships identified unmineable coal seams as potential CO
2
reservoirs.
Other partnerships identified geological formations unique to their regions—
such as organic-rich shales in the Illinois Basin, or flood basalts in the
Columbia River Plateau—as other types of possible reservoirs for CO
2
storage.
Table 2
indicates a lower and upper range for sequestration potential in
deep saline formations and for unmineable coal seams, but only a single
estimate for oil and gas fields. Comparison between the 2008 and 2010
estimates indicates small changes between the two estimates for oil and gas
fields, but relatively larger changes in estimates for deep saline formations and
unmineable coal seams. It is clear from the table that DOE considers estimates
for oil and gas fields much better constrained than for the other types of
reservoirs. The amount and types of data from oil and gas fields, such as
production history, and reservoir volume calculations, often represent decades
of experience in the oil and gas industry. In the Carbon Sequestration Atlas, oil
and gas reservoirs were assessed at the field level (i.e., on a finer scale and in
more detail) than deep saline formations or unmineable coal seams, which
were assessed at the basin level (i.e., at a coarser scale and in less detail).
Other methodologies for and estimates of the geological sequestration
potential have been released or are underway. For example, the Energy
Independence and Security Act of 2007 (EISA, P.L. 110-140) directed the
Department of the Interior (DOI) to develop a single methodology for an
assessment of the national potential for geologic storage of carbon dioxide.
The U.S. Geological Survey (USGS) released an initial methodology in 2009.
In response to external comments and reviews, the USGS revised its initial
methodology in a 2010 report.
33
According to DOE, the USGS effort will
allow refinement of the estimates provided in the 2008 Carbon Sequestration
Atlas, and will incorporate uncertainty in the capacity estimates.
34
In addition,
DOE notes that its methodology will incorporate results from large-scale
carbon sequestration demonstration projects now underway, and that it will
update its CO
2
storage estimates every two years. The DOE Sequestration
