Carbon Sequestration to Help Limit Global Climate Change










S. 731



APRIL 16, 2007 

Mr. Chairman and Members of the Committee, thank you for the opportunity to provide the Department of the Interior views on S. 731, “National Carbon Dioxide Storage

Capacity Assessment Act of 2007.”

The Administration supports the goals of the bill and agrees that the activities authorized by this bill would address a critical information need for our nation.  We cannot, however, commit to meeting the timeframes established by this bill.  We could support this bill if it were amended to address our concerns regarding the bill’s mandatory language and statutorily prescribed timeframes. The activities authorized by this bill would need to compete among the Administration’s other priorities for funding.  I look forward to working with the committee to address these issues.

Geologic Carbon Sequestration

The challenges of addressing carbon dioxide accumulation in the atmosphere are significant and the goals of S. 731 are a step forward toward addressing information needs related to geologic storage of carbon dioxide.  Fossil fuel usage, a major source of carbon dioxide emissions to the atmosphere, will continue in both industrialized and developing countries. Therefore, a variety of strategies are being investigated to reduce emissions and remove carbon dioxide from the atmosphere.  Geologic carbon sequestration is one such strategy.

Numerous carbon dioxide concentration stabilization targets have been modeled to evaluate the technical and economic feasibility of carbon dioxide capture and storage in the context of a mitigation strategy.  The current atmospheric carbon dioxide concentration is approximately 380 parts per million volume and rising at a rate of approximately 2 parts per million volume annually, according to the most recent information from the Intergovernmental Panel on Climate Change (IPCC).  The fraction of carbon emissions from all sources that must be eliminated or sequestered to impact the magnitude of climate change is large.  For example, to stabilize carbon dioxide concentrations at about 550 parts per million volume, the amount of carbon dioxide requiring elimination or sequestration may be as much as 70 percent. Reductions of this magnitude could involve implementation of several mechanisms, including geological and biological sequestration, fuel shifts from fossil sources to renewable biological sources, increased electricity generation from solar and wind systems and nuclear power, and increased efficiency of power generation, transmission, and end use.  Each of these mechanisms has distinct geological, hydrological, ecological, economic and social implications that must be assessed on a wide range of scales, from molecular to basin scales, to allow rational policy discussions and decisions on implementation and deployment of technologies. 

Geological storage of carbon dioxide in porous and permeable rocks involves injection of carbon dioxide into a subsurface rock unit and displacement of the fluid or formation water that initially occupied the pore space.  This principle operates in all types of potential geological storage formations such as oil and gas fields, deep saline water-bearing formations, or coal beds.  Because the density of injected carbon dioxide is less than the density of formation water, carbon dioxide will be buoyant in pore space filled with water and rise vertically until it is retained beneath a nonpermeable barrier (seal).  A critical issue for evaluation of storage capacity is the integrity and effectiveness of these seals.

Views on S. 731

S. 731 deals specifically with the geologic storage of carbon dioxide.  The 2005 IPCC Special Report on Carbon Dioxide Capture and Storage indicated that, in emissions reductions scenarios striving to stabilize global atmospheric carbon dioxide concentrations at targets ranging from 450 to 750 parts per million volume, the global storage capacity of geologic formations may be able to accommodate most of the captured carbon dioxide.  However, geologic storage capacity may vary on a regional and national scale, and a more refined understanding of geologic storage capacity is needed to address this knowledge gap.

S. 731 requires the Secretary of the Interior, acting through the Director of the U.S. Geological Survey (USGS), to develop a methodology for conducting a national assessment of geological storage capacity for carbon dioxide, convene a review committee to evaluate the methodology, allow for a public comment period, and conduct a national assessment of geological storage capacity for carbon dioxide.       

While the USGS does not currently have experience assessing the national capacity of geologic sequestration of carbon dioxide, USGS experience with national and international assessments of natural resources could allow USGS to develop geologically based methodologies to assess the National capacity for geologic sequestration of carbon dioxide.  We envision the national geologic carbon dioxide storage assessment methodology would be largely analogous to the peer-reviewed methodologies used in USGS oil, gas, and coal resource assessments.  In addition, the USGS’ knowledge of regional groundwater aquifer systems and groundwater chemistry would allow USGS to develop methods to assess potential storage in saline water-bearing formations (“saline aquifers”).  Previous studies have postulated the existence of very large carbon dioxidestorage capacities in saline aquifers, but the extent to which these capacities can be utilized remains unknown.  The USGS could  create a scientifically based, multi-disciplinary methodology for geologic carbon dioxide storage assessment that can be consistently applied on a national scale. 

Under this bill, the USGS would coordinate and cooperate with the Department of Energy, the Environmental Protection Agency, other Department of Interior bureaus, State geological surveys and other relevant entities that are carrying out carbon sequestration activities to ensure the usefulness and success of the assessment.   Many states already have some storage capacity data already developed, most of which is compiled in the National Carbon Sequestration Atlas published by the Department of Energy.  The data for this atlas was compiled by the Regional Carbon Sequestration Partnerships which my colleague from the Department of Energy previously mentioned.  

Concerns with S. 731

Section 3 of the bill requires that the Secretary develop a methodology within 270 days of enactment of the bill with subsequent mandatory requirements for review and comment, independent verification, and final publication.  Additionally, Section 4 of the bill requires the Secretary to complete a national assessment within two years after the methodology is finalized.  The Administration supports a national assessment, but the activities authorized under this bill must compete under the normal prioritization, budgetary, and funding processes.  To ensure that this happens, the bill would have to be amended to provide flexible timeframes that will   ensure that the national assessment will be funded consistent with other Administration and Congressional priorities.  The bill does not provide sufficient time to develop the methodology and carry out the required assessment.  USGS needs flexibility to ensure that we are able to develop the best product.  Furthermore, to ensure appropriate flexibility in budgetary management, the Administration recommends that this bill be amended to authorize rather than require the national assessment.  We would like to work with the committee to revise the bill to address these issues.  If the bill is amended to satisfactorily address these concerns, the Administration would support it.

In conclusion, the Administration agrees with the goals of the bill to develop a standard, peer reviewed methodology to assessthe nation’s geologic storage capacity of carbon dioxide and produce a national scale assessment using this methodology.  We would also like to underline the importance of using a collaborative and non-duplicative inter-agency approach to build on the existing data, including DOE’s National Carbon Sequestration Atlas.  The activities authorized in this bill would ultimately result in a geologically based, robust, and peer-reviewed national scale assessment and I look forward to working with the Committee on important revisions to the bill to ensure that the Administration would be able to support it. 

Thank you, Mr. Chairman, for the opportunity to present this testimony.  I will be pleased to answer questions you and other Members of the Committee might have.