Literature research conducted by a blue ribbon expert panel convened by the National Academies in the United States has reached the conclusion that proposed injection volumes of liquid CO2 in large-scale sequestration projects (> 1 million metric tonnes per year) have the potential to increase the pore pressure over vast areas. Relative to other technologies, such large affected areas may have the potential to increase both the number and magnitude of seismic events. In other words, sequestration of carbon dioxide in deep rock formations may cause earthquakes.
No commercial scale sequestration sites of this scale are currently operating anywhere in the world but the Canadian government has announced an investment of approximately $1.4 billion in Carbon Capture and Storage development and the Government of Alberta has announced a $2 billion investment in four large-scale carbon capture and storage projects.
The National Academies study describes what we know about the potential for induced seismicity related to energy development. It highlights areas where our knowledge is weak and discusses inherent difficulties in dealing with an issue that does not have a well-defined regulatory “home.” The committee concludes that:
- the process of hydraulic fracturing a well as presently implemented for shale gas recovery does not pose a high risk for inducing felt seismic events;
- injection for disposal of waste water derived from energy technologies into the subsurface does pose some risk for induced seismicity, but very few events have been documented over the past several decades relative to the large number of disposal wells in operation; and
- CCS, due to the large net volumes of injected fluids, may have potential for inducing larger seismic events.
The report, to be published as a book by The National Academies Press, is currently available in prepublication form from http://download.nap.edu/catalog.php?record_id=13355