New science gauges potential to store CO2
A new method to assess the US's potential for storing carbon dioxide could lead to techniques for lessening the impacts of climate change, according to Secretary of the Interior Ken Salazar, who praised a U.S. Geological Survey report in an energy teleconference today.
The USGS released the report to describe its methodology to assess the nation's potential for carbon sequestration--the injection of liquid carbon dioxide into rocks below the earth's surface.
The new methodology identifies a means to assess the volume of pore space in subsurface rocks that is able to store carbon dioxide for tens of thousand of years.
'Rather than emitting carbon into the air, our nation can and should move toward capturing carbon emissions and storing them underground,' said Salazar. 'The report will help us find the best places in the country for this type of carbon sequestration. The development of this assessment methodology marks a critical first step in our understanding of how much carbon dioxide can be stored in the subsurface.'
As a senator in 2007, Salazar authored the provision of the Energy Independence and Security Act that directed USGS to develop the methodology. 'The USGS is uniquely qualified to undertake this effort, given their experience with national and international assessments of natural resources, such as oil and gas, and their knowledge of ground-water systems and chemistry,' he said today.
The true global storage capacity of carbon dioxide in geologic formations is unknown at this point, and this method allows for an assessment that can characterize the storage potential in two types of storage units (saline formations and oil and gas reservoirs) in a uniform manner across the United States.
This assessment methodology for storing carbon dioxide focuses on the 'technically accessible resource,' which is the geologic resource that may be available and sequestered using present-day geological and engineering knowledge and technology. No economic factors are used in the estimation of the volume of resource.
The methodology is dependent upon building geologic models of the areas to be assessed. Statistical methods are used to incorporate uncertainty and natural geologic variability on the ranges of possible storage resources within a storage assessment unit.
This research benefited from discussions with a variety of partners and stakeholders, such as the Department of Energy and the National Energy Technology Laboratory, State Geological Surveys, the Environmental Protection Agency, and the Bureau of Land Management. The USGS will accept technical comments on the methodology from the public in the near future.
The USGS is conducting research on a number of fronts related to carbon sequestration. These efforts include evaluation of potential biological sequestration in a variety of ecosystems, potential release of greenhouse gases from Arctic soils and permafrost, mapping the distribution of ultramafic rocks for potential mineral sequestration efforts, and the possible role of gas hydrates in carbon sequestration.