Climate Change

What is carbon dioxide capture and sequestration?

Why is it important?

What sources of carbon dioxide can it be applied to?

Where can captured carbon dioxide be stored?

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Quick Fact

What's the difference between carbon 

dioxide capture and sequestration 

(CCS) and geologic sequestration?

Geologic sequestration is one step in the 

CCS process. Unlike terrestrial, or 

biologic, sequestration, where carbon is 

stored via agricultural and forestry 

practices, geologic sequestration involves 

injecting carbon dioxide deep 

underground where it stays permanently.

Learn More

EPA's Greenhouse Gas Reporting 

Program (GHGRP) collects information 

from facilities in 41 industry types that 

directly emit large quantities of GHGs, 

suppliers of certain fossil fuels, and 

facilities that inject CO2 underground.

EPA's Proposed Carbon Pollution 

Standards for New Power Plants

On September 20, 2013, the U.S. 

Environmental Protection Agency 

announced a first step under President 

Obama’s Climate Action Plan to reduce 

carbon pollution from power plants. EPA 

is proposing carbon pollution standards 

for new power plants built in the future. 

Carbon capture and sequestration is one 

of the technologies new power plants can 

employ to meet the standard.Learn more 

about the proposed standards.

Carbon Dioxide Capture and Sequestration

What is carbon dioxide capture and sequestration?

Carbon dioxide (CO2) capture and sequestration (CCS) is a set of technologies that can greatly 

reduce CO2 emissions from new and existing coal- and gas-fired power plants and large 

industrial sources. CCS is a three-step process that includes:

• Capture of CO2 from power plants or industrial processes

• Transport of the captured and compressed CO2 (usually in pipelines).

Underground injection and geologic sequestration (also referred to as storage) of the CO2

into deep underground rock formations. These formations are often a mile or more beneath

the surface and consist of porous rock that holds the CO2. Overlying these formations are 

impermeable, non-porous layers of rock that trap the CO2 and prevent it from migrating 

upward.

•

The figure below illustrates the general CCS process and shows a typical depth at which CO2

would be injected. Watch the following videos to learn more about how CCS works:

• http://prod-mmedia.netl.doe.gov/Video/carbon_sequestration_animation.wmv

• http://prod-mmedia.netl.doe.gov/Video/carbon_sequestration_sept.wmv

CCS Schematic (Subsurface depth to scale, 5,280 feet equals one mile)

Why is it important?

Carbon dioxide (CO2) capture and sequestration (CCS) could play an important role in reducing 

greenhouse gas emissions, while enabling low-carbon electricity generation from power plants. 

As estimated in the U.S. Inventory of Greenhouse Gas Emissions and Sinks , more than 40% of 

CO2 emissions in the United States are from electric power generation. CCS technologies are 

currently available and can dramatically reduce (by 80-90%) CO2 emissions from power plants 

that burn fossil fuels. Applied to a 500 MW coal-fired power plant, which emits roughly 3 million 

tons of CO2 per year, [1] the amount of GHG emissions avoided (with a 90% reduction efficiency) 

would be equivalent to:

• Planting more than 62 million trees, and waiting at least 10 years for them to grow.

• Avoiding annual electricity-related emissions from more than 300,000 homes.

To see this emissions reduction expressed in other equivalent terms, see EPA's Carbon Equivalencies Calculator.

Overview

Carbon Dioxide Capture and Sequestration | Climate Change | US EPA Page 1 of 5

http://www.epa.gov/climatechange/ccs/index.html 4/23/2014
CCS could also viably be used to reduce 

emissions from industrial process such as 

cement production and natural gas 

processing facilities.

What sources of carbon 

dioxide can it be applied 

to?

Carbon dioxide (CO2) capture and 

sequestration (CCS) can significantly 

reduce emissions from large stationary 

sources of CO2, which include coal- and 

natural-gas-fired power plants, as well as 

certain industry types such as ethanol and 

natural gas processing plants. EPA’s 

Greenhouse Gas Reporting Program 

includes facilities that capture CO2 for the 

purpose of supplying the CO2 to the 

economy or for injecting it underground 

(Subpart PP). According to the Greenhouse 

Gas Reporting Program, CO2 capture is 

currently occurring at over 120 facilities in 

the United States, mainly on industrial 

processes, and the CO2 is used for a wide 

range of end uses. End uses of CO2

include enhanced oil recovery (EOR), food 

and beverage manufacturing, pulp and

paper manufacturing, and metal fabrication. 

The figure below shows the portion of CO2

that is currently being captured from power 

plants and other industrial facilities and the 

portion that is extracted by production wells 

from natural CO2 bearing formations in the 

United States. The second figure shows the various domestic end uses of captured and extracted CO2. (Note that natural sources of CO2

are not considered in the Total CO2 Supply End Uses figure). As CCS becomes more widespread, it is expected that the portion of CO2

captured in the United States from power generation and industrial processes will increase.

Where can captured carbon dioxide be stored?

After capture, carbon dioxide (CO2) is compressed and then transported to a site where it is injected underground for permanent storage 

(also known as “sequestration”). CO2 is commonly transported by pipeline, but it can also be transported by train, truck, or ship. Geologic 

formations suitable for sequestration include depleted oil and gas fields, deep coal seams, and saline formations. The U.S. Department of

Energy estimates that anywhere from 1,800 to 20,000 billion metric tons of CO2 could be stored underground in the United States. [2] That is 

equivalent to 600 to 6,700 years of current level emissions from large stationary sources in the United States. [3]

Overview of Geologic Storage Potential in the United States (Source: U.S. Department of Energy, NATCARB)

Potential sequestration sites must undergo appropriate site characterization to ensure that the site can safely and securely store CO2. After 

being transported to the sequestration site, the compressed CO2 is injected deep underground into solid, but porous rock, such as 

sandstone, shale, dolomite, basalt, or deep coal seams. Suitable formations for CO2 sequestration are located under one or more layers of 

cap rock, which trap the CO2 and prevent upward migration. These sites are then rigorously monitored to ensure that the CO2 remains

permanently underground. The safety and security of CO2 geologic sequestration is a priority for EPA.

For more information, visit the National Carbon Sequestration Database and Geographic Information System (NATCARB), a geographic 

information system (GIS)-based tool developed to provide an overview of CCS projects and storage potential.

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WCMS

Last updated on Friday, September 20, 2013

http://www.epa.gov/climatechange/ccs/index.html Capture and Extraction Facilities CO2 Supplied in 

2011

* Source: EPA Greenhouse Gas Reporting Data - Subpart PP - Suppliers of 

Carbon Dioxide. Based on 2011 data. MMT = million metric tons

References

[1] MIT (2007) The Future of Coal: Options for a Carbon-Constrained 

World , Massachusetts Institute of Technology, 

2007. 

[2] NACAP (2012) The North American Carbon Storage Atlas , 

The U.S. Department of Energy (DOE), Natural 

Resources Canada (NRCan), and the Mexican Ministry of Energy 

(SENER).

[3] GHGRP(2012) EPA Greenhouse Gas Reporting Data–Subpart PP

–Suppliers of Carbon Dioxide. Based on 2011 data.

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Capture and Extraction Facilities CO2 Supplied to 

End Uses in 2011

* Source: EPA Greenhouse Gas Reporting Data - Subpart PP - Suppliers 

of Carbon Dioxide. Based on 2011 data. MMT = million metric tons

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