What Is Carbon Dioxide Capture and Storage?
Whenever a person drew a breath four hundred years ago, about 280 molecules out of every million that entered his lungs were carbon dioxide. Today, every breath you take contains 400 molecules per million of carbon dioxide. According to the Intergovernmental Panel on Climate Change (IPCC), this increase is a result of economic and population growth over the last forty years, largely from an increased use of fossil fuels. Fossil fuel combustion occurs in power plants, oil refineries, and large industrial facilities. Fossil fuels also generate carbon dioxide through their use in automobiles. For example, a car that gets thirty miles to the gallon will need to buy 330 gallons (about a ton) of gasoline a year; burning that much gasoline generates about three tons of carbon dioxide. Such an increase is “bringing climate change upon ourselves faster than we can learn how severe the changes will be.”
Carbon dioxide capture and storage (CCS) is a process that provides a way to decrease the amount of carbon dioxide emitted into the atmosphere. The first step of CCS involves capturing carbon dioxide produced through the combustion and preparation of fossil fuels from major stationary sources such as refineries and power plants. The captured carbon dioxide is then transported, usually by pipeline, and injected into a suitable deep rock formation. The aim of geological storage is to “replicate the natural occurrence of deep subsurface fluids, where they have been trapped for tens or hundreds of millions of years.”
For the past thirty-five years, the oil and gas industry has continuously gained experience with transporting and injecting carbon dioxide through use of in enhanced oil recovery (EOR), which offers “potential economic gain from incremental oil recovery.”  The reason for increased interest is that EOR uses carbon dioxide’s chemical and physical properties to displace hard-to-get oil left behind after the first stages of oil production. For example, when an oil field is first brought into production, the existing reservoir pressure causes oil to flow naturally to the surface; this stage of production is the primary phase and produces about 6-15% of the original oil in place. As reservoir pressure drops, water is usually injected to raise the pressure and displace the oil; this is the secondary phase and produces another 6-30% of the original oil in place. Lastly, several methods can be used to recover any remaining oil, carbon dioxide being one of them; this final stage of enhanced oil recovery is the tertiary stage and produces another 8-20% of the original oil in place. In the United States alone, the oil and gas industry operates over 13,000 carbon dioxide EOR wells has injected over 600 million tons of carbon dioxide and produces about 245,000 barrels of oil per day from carbon dioxide EOR projects.
Potential Dangers and Risks of Carbon Dioxide Capture and Storage
Carbon dioxide’s effects on humans are relatively well understood, but volcanic regions (where carbon dioxide seepage often occurs) further illustrate the widespread effects that large amounts of carbon dioxide can have on the surrounding environment. For example, because carbon dioxide is 50% denser than breathable air, carbon dioxide leaked into the atmosphere tends to migrate downwards and can accumulate to dangerous concentrations in low-lying areas. Whenever concentrations of carbon dioxide in the atmosphere rise above 7-10%, humans run the risk of losing consciousness and death through asphyxiation. Vegetation is also affected. Although an increase in atmospheric carbon dioxide would accelerate plant growth, too much of an increased carbon dioxide concentration would lead to root anoxia, which cases plant death and outweighs any potential benefits from increased growth.
With CCS, physical leakage from a storage site is possible in either one of two ways: gradual or long-term release, which would counter the purpose of CCS by returning carbon dioxide into the atmosphere, or sudden release of large amounts of carbon dioxide caused by a sudden disruption of a reservoir. Perhaps the most famous incident involving sudden release of carbon dioxide is the 1986 tragedy of Lake Nyos in Cameroon. The Lake Nyos tragedy occurred after a nearby volcano released carbon dioxide that seeped into a lake, accumulating at the bottom of the lake in a crater. One night, the lake overturned abruptly and released between 100,000 to 200,000 tons of carbon dioxide in a few hours. As a result, the gas, which is heavier than air, flowed down through two valleys and asphyxiated 1,700 nearby villagers and thousands of cattle.
The Lake Nyos tragedy illustrates the devastating effects that a sudden release of carbon dioxide can have on the surrounding area. However, the tragedy of Lake Nyos is not representative of the more probable gradual seepage through wells or fractures that may occur from geological storage sites. While the effects of gradual seepage are not as intense as sudden release, there are still some serious concerns that should be addressed.
One possible way that carbon dioxide could escape is by seeping into a shallower rock formation, eventually spreading and making its way to the surface. Corrosion of cement plugs capping abandoned wells can also allow seepage of carbon dioxide. Risks posed by gradual seepage are intensified when an abandoned well is located near a shallow drinking water aquifer because the carbon dioxide can migrate up the abandoned well and into the aquifer, contaminating the water as a result. Because of these potential risks, “[i]njection wells and abandoned wells have been identified as one of the most probable leakage pathways for CO2 storage projects.”
Other than gradual seepage of carbon dioxide, CCS poses potential risks through seismic activity in the shape of fracturing and fault activation. This is caused in two ways. First, overpressure can create or enhance the likelihood or fracturing, providing a pathway for unwanted carbon dioxide migration. Second, fault activation can induce earthquakes large enough to cause significant damage.
Because CCS is a new field whose risks are not yet fully understood, “no well-established methodology for assessing such risks exists.” As a result, “our understanding of abandoned well behavior over long time scales is . . . relatively poor,” and until CCS has been tried at a commercial scale, “it is impossible to pinpoint the exact leakage rate that would occur.” Because of the lack of knowledge dealing with the potential impermanence of CCS, “there are currently no standard protocols or established network designs monitoring leakage” of carbon dioxide. It is unknown what kind of long term monitoring will be needed, who will do the monitoring, for what purpose, and for how long. However some scholars have suggested that monitoring may be required for thousands of years.
Therefore, before large-scale implementation of CCS is attempted, it is crucial to obtain more information in several areas including the following: the storage capacity needed for a potential storage site, improved confidence in the risk of leakage and methods of leakage along with quantitative assessments of risks to human health, improved fracture detection and characterization of leakage potential, costs associated with leakage, and the regulatory scheme used for potential CCS projects and liability standards used if leakage causes damages. This is especially true when there is “little assurance that the systems and institutions of liability will be in place if and when [carbon dioxide] is released.”
Preferred Citation: Timothy Benedetto, Carbon Dioxide Capture and Storage: The Newest Conservation Phenomenon, LSU J. Energy L. & Res. Currents (September 2, 2015), https://jelr.law.lsu.edu/?p=1225.
 Robert H. Socolow, Can We Bury Global Warming?, Scientific American, July 2005, at 49.
 Jason Samenow, Atmospheric Carbon Dioxide Reaches 400 Parts Per Million Concentration Milestone, Washington Post, May 10, 2013, http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/05/10/atmospheric-carbon-dioxide-concentration-400-parts-per-million/ [http://perma.cc/Z473-SH95].
 See Summary for Policy Makers, Intergovernmental Panel on Climate Change, Climate Change 2014:Mitigation of Climate Change 7–8 (Ottmar Edenhofer et. al eds., 2014).
 Id. at 6.
 Intergovernmental Panel on Climate Change, Carbon Dioxide Capture and Storage 78 (Bert Metz et. al eds., 2005).
 Robert H. Socolow, supra note 1, at 50.
 Id. at 49.
 Intergovernmental Panel on Climate Change, supra note 5, at 199.
 Id. at 54, 199.
 Id. at 199; See Intergovernmental Panel on Climate Change, supra note 5, at 279. (Injecting captured carbon dioxide into the ocean at a great depth would also isolate it from the atmosphere, but this article will only address issues arising from geologic storage of carbon dioxide.)
 Id. at 89.
 James P. Meyer, The American Petroleum Institute, Summary of Carbon Dioxide Enhanced Oil Recovery Injection Well Technology vi (2007).
 Intergovernmental Panel on Climate Change, supra note 5, at 203, 214.
 Socolow, supra note 1, at 54.
 Meyer, supra note 12, at 1.
 Id. at vi.
 Intergovernmental Panel on Climate Change, supra note 5, at 246.
 Id. at 248.
 Id. at 373.
 Socolow, supra note 1, at 54.
 See Intergovernmental Panel on Climate Change, supra note 5, at 211.
 Denise Chow, Trapping Carbon Dioxide Underground: Can We Do It?, live science (July 02, 2013), http://www.livescience.com/37906-geologic-carbon-sequestration-climate-change.html [http://perma.cc/2L9B-TYJU].
 Robert H. Socolow, supra note 1, at 55; see also Intergovernmental Panel on Climate Change, supra note 5, at 244 fig.5.26 (detailing possible leakage pathways through or around cement plugs).
 See Intergovernmental Panel on Climate Change, supra note 5, at 231.
 Id. at 244.
 Id. at 249.
 Id. at 250.
 Id. at 251.
 Christa Marshall and Climatewire, Can Stored Carbon Dioxide Leak?, Scientific American (June 28, 2010), http://www.scientificamerican.com/article/can-stored-carbon-dioxide-leak/ [http://perma.cc/AMH9-CDSR] (“ . . . it is critical to get more wells in the ground to get more data about exact leakage speeds and optimal storage spots for [carbon dioxide] . . .”).
 Intergovernmental Panel on Climate Change, supra note 5, at 241.
 Id. at 244.
 See Semere Solomon, Bellona, Gulf Coast Carbon Center, Carbon Dioxide Storage: Geological and Environmental Issues – Case Study on the Sleipner Gas Field in Norway 66 (2007).
 Intergovernmental Panel on Climate Change, supra note 5, at 374.