The following column by AGI/AIPG Geoscience & Public Policy Intern David P. McCormick II is reprinted from the January/February 2008 issue of The Professional Geologist, a publication of the American Institute of Professional Geologists . It is reprinted with permission.
The 110th Congress has focused on climate change mitigation and has become enamored with carbon capture and storage (CCS) as perhaps the most promising solution for reducing greenhouse gas (GHG) emissions. Many bills have included CCS surveys, more research and development (R&D) and larger demonstration projects. While other measures to mitigate climate change have been introduced in Congress such as a cap and trade system, a carbon tax, and restrictions on carbon emitters, these measures are too controversial and garner much less support than CCS.
CCS legislation is more attractive to a majority in Congress because it is mostly about more R&D and does not directly involve carbon pricing, carbon taxes, regulations or restrictions. Geoscientists should be aware of decision-making with respect to CCS because they will be the experts involved in the R&D and the future direction of this popular climate change mitigation strategy.
The Renewable Fuels, Consumer Protection, and Energy Efficiency Act of 2007 provides $895 million to conduct CCS surveys, more R&D and larger demonstration projects. It has been approved by the House and the Senate and now awaits reconciliation and final approval in Congress. It is the most likely CCS legislation to gain approval by Congress and could be signed into law by the end of 2007. The bill calls for the U.S. Geological Survey (USGS) to conduct a national survey of potential CO2 storage formations and to provide geological data (e.g. well log analysis, core data and fluid sample analysis) to determine the feasibility of large scale storage. The measure also provides funding for the Department of Energy (DOE) to develop geophysical tools and methods of monitoring storage formations for large scale demonstration projects. The bill calls for at least seven demonstration projects that can store up to one million tons of CO2 each year.
The legislation identifies seven geologic formations to be studied for CCS. These formations include operating oil and gas (O&G) fields, depleted O&G fields, saline aquifers, unmineable coal seams, basalt formations, deep geologic systems that could be engineered for use in geothermal power, and coal-bed methane sites for use in methane recovery. Currently O&G fields appear to be the best option for CCS because the geology is well understood and there is additional potential for enhanced oil recovery. The DOE1 and its partnerships have estimated about 82 billion metric tons of storage capacity in the U.S. and Canada. This estimate includes O&G fields that would use CO2 for enhanced recovery. The unconventional reservoirs such as saline aquifers and unmineable coal seams are less favorable because uncertainties exist about the geology. In addition if the CO2 is sequestered in these formations it might render the currently unexploited coal and water resources unusable. Nonetheless, the DOE and its partnerships estimate 156- 184 billion metrics tons of CO2 storage capacity in unmineable coal seams and 919-3,300 billion metric tons of storage capacity in saline aquifer formations in North America. So the storage potential based on these estimates shows a much larger capacity in the saline aquifers and coal seams. Other potential storage formations will require significantly more R&D before they can be seriously considered for CCS technology. That is why in the legislation Congress recognizes that not all locations are geologically equal and careful consideration must be given to potential leakage, potential changes in the geology, health and safety concerns and environmental issues when choosing a suitable site for CO2 storage.
The legislation also identifies the primary point sources of CO2 such as fossil fuel based electricity generation, petroleum refining, iron and steel manufacturing, cement manufacturing, biofuel production and coal gasification plants. One of the major tasks in planning for effective CCS is identifying the location and capacity of all sources and sinks because one of the most expensive aspects of CCS are the CO2 pipelines. Another major concern is leakage at a storage site. Leaks can present obvious hazards to the public and even a very small leak of about one percent per year would nullify the main purpose of CCS. Such a small leak would essentially put all of the CO2 being sequestered back into the atmosphere over time and there would be no overall reduction in CO2.
While leaks are a problem, the measure deals primarily with R&D and does not get into the sticky issues of regulatory authority and liability. In the U.S. and across the globe, regulations related to the subsurface and liability issues with CCS are largely unresolved according to the Intergovernmental Panel on Climate Change's (IPCC) Special Report on Carbon Dioxide Capture and Storage2. Some countries have liability regulations for situations that are comparable to CCS, but it is not clear how these regulations might be applied to CCS. Existing U.S. laws for mining, O&G, subsurface property rights, and drinking water while relevant to CCS were written long before CCS was being considered and are likely not adequate enough to allow commercial development of CCS. In addition, CCS beneath the seafloor represents a new and more difficult area to regulate. Some treaties, such the London and Oslo-Paris Convention, deal with injection of CO2 into the subsurface seabed, however, they do not directly address storage issues.
Despite the unresolved issues of regulatory authority and liability, countries such as Norway and Canada have forged ahead on CCS projects. In Norway, the Sleipner Project, managed by Statoil, injects CO2 into the Utsira formation, a saline aquifer about 1,000 meters below the seafloor in the North Sea. The project began in 1996 and has stored about 1 million tons of CO2 a year. The development of the project is due partly to Norway's high carbon tax, about $55 per ton of CO2, on offshore oil and gas. Studies have shown that Statoil's overall CO2 emissions have dropped since the project began. In Canada, the EnCana Corporation has been injecting and storing CO2 for enhanced oil recovery in the Weyburn Field since 1997. This project was driven solely by economics because it was cheaper to get CO2 from a coal gasification plant than any other source. EnCana pipes in CO2 from the Great Plains Coal Gasification Plant in North Dakota to extend the life of their field. EnCana estimates that through CO2 injection an additional 120 million barrels of oil can be extracted. The Norwegian example suggests that CCS is feasible, relatively safe so far and can mitigate climate change. The Canadian example suggests that piping CO2 emissions from a distant source can be commercially viable for oil and gas recovery and if they can also show that the CO2 is not leaking, then it has the added benefit of mitigating climate change without carbon pricing or taxes.
Should future projects prove to be just as successful, the overall climate change mitigation impact could be substantial. According to the IPCC, the potential for CO2 storage in suitable sedimentary basins such as O&G fields is about 200- 2,200 gigatons. This could mean CCS would contribute about 15-55% of the GHG mitigation effort worldwide up through 2100 assuming target stabilization for atmospheric concentration of CO2 is between 450-750 ppm. The potential storage capacities could be greater if unconventional storage sites such as saline aquifers and unmineable coal seams prove viable in demonstration projects.
The two examples and the IPCC estimates show why Congress sees CCS as a silver bullet to mitigating climate change and advancing energy resource development. CCS has the potential to substantially reduce the amount of CO2 in the atmosphere, it can enhance energy resource recovery, it can use some existing infrastructure, it allows energy companies to diversify into a new enterprise that takes advantage of their current expertise, and it can initiate a new industry that should enhance local economies.
The DOE Carbon Sequestration Atlas may be found here.
The IPCC Special Report on Carbon Capture and Storage may be found here.
This article is reprinted with permission from The Professional Geologist, published by the American Institute of Professional Geologists. AGI gratefully acknowledges that permission.
Please send any comments or requests for information to the AGI Government Affairs Program.
Posted December 3, 2007
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