Carbon Capture and Storage (CCS)

Quick Facts

Carbon capture and storage (CCS) uses a combination of technologies to capture, transport, and store carbon dioxide (CO₂) emissions from the use of fossil fuels.
While the component technologies are currently used on industrial scales, CCS has not yet been deployed at a commercial-scale power plant, but it could be incorporated into the construction of future power plants or added as retrofits to existing power plants.
Carbon dioxide emissions from coal-fueled power plants account for significant amounts of U.S. and global emissions; CCS could help achieve dramatic reductions in CO₂ emissions from the electricity sector.

Background

Coal is a major source of energy both in the United States and globally, and it is abundant and inexpensive. However, coal consumption releases large amounts of CO₂, the primary greenhouse gas (GHG). CCS is a technology that has the potential to yield dramatic reductions in CO₂ emissions from coal use by capturing the CO₂ that is currently released to the atmosphere.

In 2006, the United States generated roughly half of its electricity from coal, and the CO₂ emissions from coal-fueled electricity generation accounted for 83 percent of CO₂ emissions from the U.S. electricity sector and 27 percent of all U.S. GHG emissions.^1,2 Coal is five to ten times less expensive than natural gas or petroleum, and the United States has enough coal to meet current consumptions for hundreds of years.³ Coal releases nearly twice as much CO₂ per unit of energy compared to natural gas.⁴

Given the extensive use of coal, the large amount of GHG emissions associated with coal-fueled electricity generation, and the high CO₂ emissions rate of coal, CCS coupled with coal-fueled power generation has the potential to significantly reduce GHG emissions. The high capital costs and economies of scale of CCS make large power plants attractive targets for CCS deployment.⁵ However, to date, CCS has not been deployed at any commercial-scale coal-fueled power plant.

CCS uses a combination of technologies to capture the CO₂ released by fossil fuel use, transport the CO₂ to a suitable storage location, and store the CO₂ (typically deep underground) where it cannot enter the atmosphere and, thus, does not contribute to climate change. The current status of these different technologies varies and is discussed further below.

Given the magnitude of CO₂ emissions from coal use for electricity and the opportunity for economies of scale, the greatest potential for CCS is with coal-fueled power plants. Three primary methods are discussed for CO₂ capture from coal-fueled power plants:

Pre-Combustion Carbon Capture
Coal is gasified (rather than combusted) to produce a synthesis gas, or syngas, consisting mainly of carbon monoxide (CO) and hydrogen (H₂). A subsequent shift reaction converts the CO to CO₂, and then a physical solvent typically separates the CO₂ from H₂.

For power generation, pre-combustion carbon capture can be combined with an integrated gasification combined cycle (IGCC) power plant that burns the H₂ in a combustion turbine and uses the exhaust heat to power a steam turbine.
Post-Combustion Carbon Capture
Post-combustion capture typically uses chemical solvents to separate CO₂ out of the flue gas of a pulverized coal (PC) power plant.
Oxyfuel Carbon Capture
Oxyfuel capture requires combustion of coal in pure oxygen (rather than air) so that the exhaust gas is CO₂-rich, which facilitates capture.

Once captured, CO₂ must be transported from its source to a storage site. Pipelines like those used for natural gas present the best option for terrestrial CO₂ transport.

The primary option for storing captured CO₂ is injecting it into geologic formations deep underground, including:

Deep Saline Formations
The largest potential for geologic storage in the United States is in deep saline formations, which are underground porous rock formations infused with brine.⁶ The United States has geological formations sufficient to safely and indefinitely store CO₂ from centuries of continued coal use.⁷
Enhanced Oil Recovery Using CO₂ (CO₂-EOR)
CO₂-EOR involves the injection of CO₂ into oil wells to increase the amount of oil that can be extracted. West Texas and the Gulf Coast have a 30-year history of CO₂-EOR. There is significant potential for use of captured CO₂ in EOR, and revenue from selling captured CO₂ to EOR operators could help defray the cost of CCS as power plants adopt the technology.⁸

Environmental Benefit/Emission Reduction Potential

CCS technology has the potential to reduce CO₂ emissions from a coal-fueled power plant by as much as 90 percent.⁹ CCS is forecast to provide significant CO₂ emission reductions:

The U.S. Environmental Protection Agency’s (EPA) modeling analysis of the Lieberman-Warner Climate Security Act of 2008 projected that, under the proposed cap-and-trade program, power plants with CCS would provide 28 percent and 38 percent of all U.S. electricity by 2030 and 2050, respectively.¹⁰
Modeling done by the International Energy Agency (IEA) forecasts that CCS could provide 20 percent of total global GHG emission reductions by 2050.¹¹

Cost

New coal-fueled power plants (PC or IGCC) can be designed to incorporate CCS from the start of their operation, and existing plants can be retrofit for CCS. Retrofitting existing plants for CCS is expected to be more expensive (in terms of dollars per metric ton of CO₂ avoided and the incremental impact on the levelized cost of electricity) than building new plants to incorporate CCS from the start.¹² New coal plants built without CCS can include upfront investments that lower the cost of later retrofitting the plants for CCS.¹³

The incremental cost of CCS varies depending on parameters such as the choice of capture technology, the percentage of CO₂ captured, the type of coal used, and the distance to and type of geologic storage.

For example, a 2007 study by researchers at Carnegie Mellon University estimated that, compared to an IGCC plant without CCS, a new IGCC plant built with CCS that captured 90 percent of CO₂ emissions would produce electricity at a 42 percent higher levelized cost and reduce GHG emissions at a cost of $32 per metric ton of CO₂ avoided ($32/tCO₂) in 2005 dollars (with capture, transport, and storage accounting for 75, 9, and 16 percent of this cost, respectively).¹⁴

Another study estimated that carbon capture at a coal-fueled power plant would cost $25-65/tCO₂ with CO₂ transport and storage adding $12-15/tCO₂.¹⁵ The cost of CCS is expected to be higher for the first projects and to decline thereafter as the technology moves along its “learning curve.”^16,17

Current Status of CCS

Currently, there are no commercial-scale power plants that employ CCS; however, several demonstration projects are underway or planned.¹⁸The statuses of the CCS component technologies are reviewed below.

Carbon Capture
Carbon capture technologies have long been used for industrial processes like natural gas processing and CO₂ generation for the food and beverage industry. Projects in the United States and elsewhere are underway to demonstrate carbon capture with coal-fueled power plants.
CO₂ Transport
The United States already has more than 3,000 miles of CO₂ pipelines used to transport CO₂ for EOR.¹⁹ CO₂ pipeline transport is commercially proven.
CO₂ Storage
The U.S. Department of Energy (DOE) has been supporting Regional Partnerships focused on geologic CO₂ storage since 2003.²⁰ The partnerships are initiating large-scale tests to determine how geologic storage reservoirs and their surroundings respond to large amounts of injected CO₂ in a variety of geologic formations and regions across the United States.

Worldwide, other large-scale projects for geologic CO₂ storage have been underway for a number of years, and monitoring has shown that the CO₂ is remaining safely in the target reservoirs.²¹

Obstacles to Further Development or Deployment of CCS

Lack of a Price on Carbon or GHG Emission Performance Standards
Deploying CCS at a coal-fueled power plant (new-build or retrofit) requires large incremental investments in capital equipment and higher operating costs. A policy, such as cap and trade (see Climate Change 101: Cap and Trade), that places a financial cost on GHG emissions, or policies that otherwise limit GHG emissions, are crucial for spurring firms to invest in CCS.
Need for Initial Commercial-Scale CCS Projects
The first commercial-scale CCS projects integrated with power plants will generate valuable information on the actual cost and performance of CCS as well as the optimal configuration of the technologies. Large-scale, real-world CCS projects will provide much-needed data to guide firms’ investments in CCS and will lead to cost reductions via technology improvements.
Uncertainty in CO₂ Storage Regulations
Regulations for CO₂ storage are needed to specify: site selection criteria; well, injection, and closure operational requirements; long-term monitoring and verification requirements; and long-term liability.

Policy Options to Help Promote CCS

Putting a Price on Carbon
Policies that place a price on GHG emissions, such as a cap and trade, would discourage investments in traditional fossil-fuel use and spur investments in a range of clean energy technologies, including CCS.
Funding for Initial CCS Projects
To foster the initial, large-scale CCS projects needed to fully demonstrate the technology, the government can offer financial incentives for CCS. For example, the government could create a trust fund that could competitively award money to CCS projects to help them overcome financing hurdles.²²

A study prepared for the Pew Center found that coal power plant owners would require between $300 and $650 million in funds to cover the investments in equipment and lost capacity necessary for the initial commercial-scale deployments of CCS, depending on the plant type and whether plants are newly built with CCS or retrofit.²³
Mandating GHG Emission Rates
Policymakers could rely on performance standards to drive CCS deployment by enacting new regulations that require CCS via a new source performance standard for power plants or a low-carbon performance standard (similar to the renewable portfolio standards that many states already have). Illinois enacted such a policy in 2009.²⁴
Defining a CO₂ Storage Regulatory Framework
Uncertainty regarding the legal framework governing CO₂ storage may hinder investment in CCS. In particular, the government may have a role in assuming long-term liability for stored CO₂. For example, charges levied on injected CO₂ could feed a CO₂ Storage Fund that could assume long-term liability from stored CO₂ from private-sector entities.

Business Environmental Leadership Council (BELC) Company Activities Related to CCS

Related Pew Center Resources

Addressing Emissions from Coal Use in Power Generation, 2008

Climate Change 101: Technology, 2009

Coal and Climate Change Facts, 2008

Coal Initiative Reports

A Program to Accelerate the Deployment of CO₂ Capture and Storage: Rationale, Objectives, and Cost, 2007.
A Resource and Technology Assessment of Coal Utilization in India, 2008.
State Options for Low-Carbon Coal Policy, 2008.
A Trust Fund Approach to Accelerating Deployment of CCS: Options and Considerations, 2007.

Creating Power, Technology, and Products: The Role of Coal Gasification in Ohio’s Economy and Energy Future, 2007.

The Role of CO₂ Enhanced Oil Recovery in Ohio's Economy and Energy Future, 2007.

The U.S. Electric Power Sector and Climate Change Mitigation, 2005.

Further Reading/Additional Resources

Battelle Memorial Institute, Carbon Dioxide Capture and Geologic Storage, 2006.

CCSReg Project

Congressional Research Service, Capturing CO₂ from Coal-Fired Power Plants: Challenges for a Comprehensive Strategy, 2008.

Congressional Research Service, Carbon Capture and Sequestration (CCS), 2009.

Government Accountability Office (GAO), Climate Change: Federal Actions Will Greatly Affect the Viability of Carbon Capture and Storage as a Key Mitigation Option, 2008.

International Energy Agency (IEA) Greenhouse Gas R&D Programme.

Massachusetts Institute of Technology (MIT)

McKinsey & Company, Carbon Capture and Storage: Assessing the Economics, 2008.

Natural Resources Defense Council (NRDC) and Environmental Defense Fund (EDF). Carbon Capture and Sequestration Public Workshops, February 2008 and March 2009, Presentations and Bibliography.

U. S. Department of Energy (DOE)

Carbon Sequestration Program
National Energy Technology Laboratory (NETL), Technologies: Carbon Sequestration

World Resources Institute (WRI), Carbon Capture and Sequestration Project

¹ U.S. Energy Information Administration (EIA), Electric Power Annual with Data for 2007, 2009.
² U.S. Environmental Protection Agency (EPA), Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2007, 2009.
³ Pew Center on Global Climate Change, Coal and Climate Change Facts, 2008.
⁴ Schrag, Daniel. 2007. “Preparing to Capture Carbon.” Science 315: 812-13, 2007.
⁵ Anderson, S. and R. Newell, “Prospects for Carbon Capture and Storage Technologies.” Annual Review of Environment and Resources 29: 109-42, 2004.
⁶ National Energy Technology Laboratory (NETL), Carbon Sequestration Atlas of the United States and Canada, 2007.
⁷ Ibid.
⁸ NETL, Storing CO₂ with Enhanced Oil Recovery, 2008.
⁹ NETL, Cost and Performance Baseline for Fossil Energy Plants: Volume 1: Bituminous Coal and Natural Gas to Electricity, 2007.
¹⁰ EPA, “EPA Analysis of the Lieberman-Warner Climate Security Act of 2008.” ADAGE Model Scenario 2. 2008.
¹¹ Mandil, Claude. The Role of CCS in Climate Change Mitigation. IEA-CSLF Early Opportunities Workshop – Global Assessment. Oslo, Norway. June 21-22, 2008.
¹² Massachusetts Institute of Technology (MIT), The Future of Coal: Options for a Carbon-Constrained World, 2007.
¹³ Bohm, M. C., H. Herzog, J. E. Parsons, and R. C. Sekar, “Capture-Ready Coal Plants—Options, Technologies and Economics.” International Journal of Greenhouse Gas Control 1(1): 113-120, 2007.
¹⁴ Rubin, E., C. Chen, and A. Rao, “Cost and Performance of Fossil Fuel Power Plants with CO2 Capture and Storage.” Energy Policy 35: 4444-4454, 2007,
¹⁵ Battelle Memorial Institute, Carbon Dioxide Capture and Geologic Storage, 2006.
¹⁶ McKinsey & Company, Carbon Capture and Storage: Assessing the Economics, 2008.
¹⁷ Kuuskraa, Vello. A Program to Accelerate the Deployment of CO₂ Capture and Storage
(CCS): Rationale, Objectives, and Costs. Prepared for the Pew Center on Global Climate Change, 2007.
¹⁸ For details on operating and planned CCS projects, see the MIT Carbon Capture and Sequestration Project’s Carbon Dioxide Capture and Storage Project Database.
¹⁹ Battelle Memorial Institute, 2006.
²⁰ U.S. Department of Energy (DOE) Carbon Sequestration Regional Partnerships.
²¹ International Emissions Trading Association, Carbon Dioxide Capture and Geological Storage as a Clean Development Mechanism Project Activity, June 2008, see Annex.
²² Pena, N. and E. Rubin. A Trust Fund Approach to Accelerating Deployment of CCS: Options and Considerations. Prepared for the Pew Center on Global Climate Change, 2008.
²³ Kuuskraa, 2007.
²⁴ For details on Illinois' CCS-related policies, click here.

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