Carbon Capture Technology Assessment: In Brief

Carbon Capture Technology Assessment:

In Brief

(name redacted)

Specialist in Energy and Natural Resources Policy

November 5, 2013

Congressional Research Service

7-....

www.crs.gov

R43300

Carbon Capture Technology Assessment: In Brief

Summary

Carbon capture and sequestration (CCS) is widely seen as a critical strategy for limiting

atmospheric emissions of carbon dioxide (CO2)—the principal “greenhouse gas” linked to global

climate change—from power plants and other large industrial sources. This report focuses on the

first component of a CCS system, the CO2 capture process. Unlike the other two components of

CCS, transportation and geologic storage, the CO2 capture component of CCS is heavily

technology-dependent. For CCS to succeed at reducing CO2 emissions from a significant fraction

of large sources in the United States, CO2 capture technologies would need to be deployed

widely. Widespread commercial deployment would likely depend, in part, on the cost of the

technology deployed to capture CO2. This report summarizes prospects for improved, lower-cost

technologies for each of the three current approaches to CO2 capture: post-combustion capture;

pre-combustion capture; and oxy-combustion capture. CRS Report R41325, Carbon Capture: A

Technology Assessment, provides a more detailed analysis of these technologies.

While all three approaches are capable of high capture efficiencies (typically about 90%), the

major drawbacks of current processes are their high cost and the large energy requirements for

operation. Another drawback is that at present there are still no full-scale applications of CO2

capture on a coal-fired or gas-fired power plant; these plants produce over a third of total U.S.

CO2 emissions from fossil fuel combustion. However, a number of large-scale demonstration

projects at both coal combustion and gasification-based power plants are planned or underway in

the United States and elsewhere. Substantial research and development (R&D) activities are also

underway in the United States and elsewhere to develop and commercialize lower-cost capture

systems with smaller energy penalties. Current R&D activities include development and testing

of new or improved solvents that can lower the cost of current post-combustion and precombustion capture, as well as research on a variety of potential “breakthrough technologies”

such as novel solvents, sorbents, membranes, and oxyfuel systems that hold promise for even

lower-cost capture systems.

The future use of coal in the United States will likely depend on whether and how CCS is

deployed if legislative or regulatory actions curtail future CO2 emissions. Congressional interest

in CCS was renewed when the U.S. Environmental Protection Agency (EPA) re-proposed

standards for carbon dioxide (CO2) emissions from new fossil-fueled power plants on September

20, 2013. These re-proposed standards would not apply to existing power plants. As re-proposed,

the standards would limit emissions of CO2 to no more than 1,100 pounds per megawatt-hour of

production from new coal-fired power plants and between 1,000 and 1,100 for new natural gasfired plants. According to EPA, new natural gas-fired stationary power plants should be able to

meet the proposed standards. However, new coal-fired plants only would be able to meet the

standards by installing CCS technology, which could add significant capital costs.

In general, the focus of most current R&D activities is on cost reduction rather than additional

gains in CO2 capture efficiency. Key questions include: when would advanced CO2 capture

systems be available for commercial rollout; and how much cheaper they would be compared to

current technology. “Technology roadmaps” developed by governmental and private-sector

organizations anticipate that CO2 capture may be available for commercial deployment at power

plants by 2020. Some roadmaps also project that some novel, lower-cost technologies may be

commercial by 2020. Such projections acknowledge, however, that this will require aggressive

efforts to advance promising concepts to commercial viability.

Congressional Research Service

Carbon Capture Technology Assessment: In Brief

Achieving significant cost reductions would likely require a vigorous and sustained level of R&D

and also a significant market for CO2 capture. At present such a market does not exist. While

various types of incentive programs can accelerate the development and deployment of CO2

capture technology, actions that significantly limit emissions of CO2 to the atmosphere ultimately

would be needed to realize substantial and sustained reductions in the future cost of CO2 capture.

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Carbon Capture Technology Assessment: In Brief

Contents

Introduction...................................................................................................................................... 1

Structure of this Report.............................................................................................................. 2

Other CRS Reports on CCS ...................................................................................................... 2

Background ...................................................................................................................................... 3

Overview.......................................................................................................................................... 4

Current Research and Development (R&D) Activities ............................................................. 5

Future Outlook........................................................................................................................... 6

Figures

Figure 1. Schematic of a CCS System, Consisting of CO2 Capture,

Transport, and Storage .................................................................................................................. 4

Tables

Table 1. Post-Combustion Capture Approaches Being Developed

at Laboratory or Bench Scale ....................................................................................................... 6

Contacts

Author Contact Information............................................................................................................. 8

Congressional Research Service

Carbon Capture Technology Assessment: In Brief

Introduction

Congressional interest in carbon capture and sequestration (or carbon capture and storage, CCS)

has been renewed since the U.S. Environmental Protection Agency (EPA) re-proposed standards

for carbon dioxide (CO2) from new fossil-fueled power plants on September 20, 2013. As reproposed, the standards would limit emissions of CO2 to no more than 1,100 pounds per

megawatt-hour of production from new coal-fired power plants and between 1,000 and 1,100

(depending on size of the plant) for new natural gas-fired plants. The standards would not apply

to existing facilities. EPA proposed the standard under Section 111 of the Clean Air Act.1

According to EPA, new natural gas-fired stationary power plants should be able to meet the

proposed standards without additional cost or the need for add-on control technology. However,

new coal-fired plants only would be able to meet the standards by installing carbon capture and

sequestration (CCS) technology. The proposed standard would allow an option of up to seven

years for a new coal-fired plant to comply. But that option would require a more stringent

standard for those plants and limit CO2 emissions to an average of 1,000-1,050 pounds per

megawatt-hour over the seven-year period.

The promise of CCS lies in the potential for technology to capture CO2 emitted from large,

industrial sources, thus significantly decreasing CO2 emissions without drastically changing U.S.

dependence on fossil fuels, particularly coal, for electricity generation. The future use of coal—a

significant component of the U.S. energy portfolio—in the United States will likely depend on

whether and how CCS is deployed if legislative or regulatory actions curtail future CO2

emissions. The September 20, 2013, proposed rule for limiting CO2 emissions from new fossilfueled power plants is one such action. In addition, Section 111 of the Clean Air Act requires that

EPA develop guidelines for pollutants—which has been interpreted to include greenhouse gas

emissions—for existing plants whenever it promulgates standards for new power plants. In a June

25, 2013, memorandum, President Obama directed the EPA to issue proposed guidelines for

existing plants by June 1, 2014, and to issue final guidelines a year later.2 These proposed actions

will likely draw additional congressional scrutiny of the viability of large-scale CCS as the

primary technology for mitigating CO2 emissions from coal-fired power plants.

Unlike the other two components of CCS, transportation and geologic storage, the first

component of CCS—CO2 capture—is almost entirely technology-dependent. For CCS to succeed

at reducing CO2 emissions from a significant fraction of large sources in the United States, CO2

capture technology would need to be deployed widely. Widespread commercial deployment

would likely depend on the cost of capturing CO2, although other factors, such as incentives for

reducing greenhouse gas emissions, would also influence deployment.

1

Since 2009, EPA has begun to address emissions of greenhouse gases from both mobile and stationary sources, using

broad regulatory authority provided by Congress decades ago in the Clean Air Act. Although Congress has never

specifically directed EPA to regulate emissions of greenhouse gases, the Clean Air Act as enacted in 1970 and as

amended in 1977 and 1990 gave the agency authority to identify air pollutants and promulgate regulations to limit their

emission. For more information see CRS Report R43127, EPA Standards for Greenhouse Gas Emissions from Power

Plants: Many Questions, Some Answers, by (name redacted).

2

Office of the Press Secretary, The White House, “Power Sector Carbon Pollution Standards,” Memorandum for the

Administrator of the Environmental Protection Agency, June 25, 2013, http://www.whitehouse.gov/the-press-office/

2013/06/25/presidential-memorandum-power-sector-carbon-pollution-standards.

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Carbon Capture Technology Assessment: In Brief

The transportation and storage components of CCS are not nearly as technology-dependent as the

capture component. Nonetheless, transportation and sequestration costs, while generally much

smaller than capture costs, could be very high in some cases. They would depend, in part, on how

long it would take to reach an agreement on a regulatory framework to guide long-term CO2

injection and storage, and on what those regulations would require. CCS deployment would also

depend on the degree of public acceptance of a large-scale CCS enterprise. Several CRS reports

(see below) address these policy issues of CO2 transportation and storage.

Structure of this Report

This report is a brief summary of a longer study—CRS Report R41325, Carbon Capture: A

Technology Assessment—that provides a “snapshot” of technological development current

through mid-2010. The technology assessment is both prospective and retrospective in that it

examines emerging or advanced technologies that may affect future CCS deployment, and looks

at lessons from past experience with large-scale technological development and deployment as

guidelines that could be used to shape energy policy. The longer report consists of 10 chapters,

together with figures and tables.

This report and the longer CRS report focus on the first component of a CCS system, namely, the

CO2 capture process. The goal of these reports is to provide a realistic assessment of prospects for

improved, lower-cost technologies for each of the three current approaches to CO2 capture.

The technology assessment was undertaken by Carnegie Mellon University, Department of

Engineering and Public Policy, under the leadership of Edward S. Rubin, together with Aaron

Marks, Hari Mantripragada, Peter Versteeg, and John Kitchin. The work was performed under

contract to CRS, and is part of a multiyear CRS project to examine different aspects of U.S.

energy policy. (name redacted), CRS Specialist in Energy and Natural Resources Policy, served as the

CRS project coordinator.

CRS Report R41325, Carbon Capture: A Technology Assessment, was funded, in part, by a grant

from the Joyce Foundation.

Other CRS Reports on CCS

CRS has written a suite of products on different aspects of CCS that complement this assessment

of carbon capture technologies. These include:

•

CRS Report R42532, Carbon Capture and Sequestration (CCS): A Primer, by

(name redacted).

•

CRS Report R42496, Carbon Capture and Sequestration: Research,

Development, and Demonstration at the U.S. Department of Energy, by (name

redacted).

•

CRS Report R43028, FutureGen: A Brief History and Issues for Congress, by

(name redacted).

•

CRS Report R42950, Prospects for Coal in Electric Power and Industry, by

(name redacted), (name redacted), and (name redacted).

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Carbon Capture Technology Assessment: In Brief

•

CRS Report RL33971, Carbon Dioxide (CO2) Pipelines for Carbon

Sequestration: Emerging Policy Issues, by (name redacted), (name redacted), and

(name redacted).

•

CRS Report R40103, Carbon Control in the U.S. Electricity Sector: Key

Implementation Uncertainties, by (name redacted).

•

CRS Report RL34316, Pipelines for Carbon Dioxide (CO2) Control: Network

Needs and Cost Uncertainties, by (name redacted) and (name redacted).

•

CRS Report RL34307, Legal Issues Associated with the Development of Carbon

Dioxide Sequestration Technology, by (name redacted) and (name redacted).

•

CRS Report RL34601, Community Acceptance of Carbon Capture and

Sequestration Infrastructure: Siting Challenges, by (name redacted).

•

CRS Report R43127, EPA Standards for Greenhouse Gas Emissions from Power

Plants: Many Questions, Some Answers, by (name redacted).

Background

Global climate change is an issue of major international concern and the focus of proposed

mitigation policy measures in the United States and elsewhere. In this context, CCS technology

has received increasing attention over the past decade as a potential method of limiting

atmospheric emissions of CO2—the principal “greenhouse gas” linked to climate change.

Worldwide interest in CCS stems principally from three factors. First is a growing consensus that

large reductions in global CO2 emissions are needed to avoid serious climate change impacts.3

Because electric power plants are a major source of CO2, curtailing their emissions has become a

focus.

Second is the growing realization that large emission reductions cannot be achieved easily or

quickly simply by using less energy or by replacing fossil fuels with alternative energy sources

that emit little or no CO2. The reality is that the world (and the United States itself) today relies

on fossil fuels for over 85% of its energy use (including fuel for transportation, not just electricity

generation). Changing that picture dramatically would take time. CCS thus offers a way to get

large CO2 reductions from power plants and other industrial sources until cleaner, sustainable

energy technologies can be widely deployed.

Finally, energy-economic models show that adding CCS to the suite of other GHG reduction

measures significantly lowers the cost of mitigating climate change. Studies also have affirmed

that by 2030 and beyond, CCS is a major component of a cost-effective portfolio of emission

reduction strategies.4

3

National Research Council, America’s Climate Choices: Limiting the Magnitude of Future Climate Change, The

National Academies Press, Washington, DC, May 2010; S. Solomon et al., eds., Climate Change 2007: The Physical

Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on

Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, 2007.

4

J. Edmonds, “The Potential Role of CCS in Climate Stabilization,” Proc. 9th International Conference on Greenhouse

Gas Control Technologies, 2008, Washington, DC; B. Metz, et al., eds., Climate Change 2007: Mitigation.

Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate

(continued...)

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Carbon Capture Technology Assessment: In Brief

Figure 1 depicts the overall CCS process applied to a power plant or other industrial process. The

CO2 produced from carbon in the fossil fuels or biomass feedstock is first captured, then

compressed to a dense liquid to facilitate its transport and storage. The main storage option is

underground injection into a suitable geological formation.

At the present time, CCS is not commercially proven in the primary large-scale application for

which it is envisioned—electric power plants fueled by coal or natural gas. Furthermore, the cost

of CCS today is relatively high, due mainly to the high cost of CO2 capture (which includes the

cost of CO2 compression needed for transport and storage). This has prompted a variety of

government and private-sector research programs in the United States and elsewhere to develop

more cost-effective methods of CO2 capture.

Figure 1. Schematic of a CCS System, Consisting of CO2 Capture,

Transport, and Storage

Fossil Fuels;

Biomass

Air or

Oxygen

Power Plant

or Industrial

Process

CO2

USEFUL

PRODUCTS

(e.g., electricity, fuels,

chemicals, hydrogen)

CO2

Capture &

Compress

CO2

Transport

CO2 Storage

(Sequestration)

- Post-combustion

- Pre-combustion

- Oxyfuel combustion

- Pipeline

- Tanker

- Depleted oil/gas fields

- Deep saline formations

- Unmineable coal seams

- Deep Ocean

- Mineralization

- Reuse

Source: E. S. Rubin, “Will Carbon Capture and Storage be Available in Time?,” American Association for the

Advancement of Science, Annual Meeting, San Diego, CA, February 18-22, 2010.

Notes: Carbon inputs may include fossil fuels and biomass. Technical options are listed below each stage. Those

in italics are not available or implemented at a commercial scale.

Overview

The following is an assessment of prospects for CCS capture technologies; namely, postcombustion capture from power plant flue gases using amine-based solvents such as

monoethanolamine (MEA) and ammonia; pre-combustion capture (also via chemical solvents)

from the synthesis gas produced in an integrated coal gasification combined cycle (IGCC) power

plant; and oxy-combustion capture, in which high-purity oxygen rather than air is used for

(...continued)

Change, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

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Carbon Capture Technology Assessment: In Brief

combustion in a pulverized coal (PC) power plant to produce a flue gas with a high concentration

of CO2 amenable to capture without a post-combustion chemical process.

Currently, post-combustion and pre-combustion capture technologies are commercial and widely

used for gas stream purification in a variety of industrial processes. Several small-scale

installations also capture CO2 from power plant flue gases to produce CO2 for sale as an industrial

commodity. Oxy-combustion capture, however, is still under development and is not currently

commercial.

The advantages and limitations of each of these three methods are discussed in CRS Report

R41325, Carbon Capture: A Technology Assessment, along with plans for their continued

development. While all three approaches are capable of high CO2 capture efficiencies (typically

about 90%), the major drawbacks of current processes are their high cost and the large energy

requirement for operation (which significantly reduces the net plant capacity and contributes to

the high cost of capture). Another drawback in terms of their availability for greenhouse gas

mitigation is that at present, there are still no applications of CO2 capture on a coal-fired or gasfired power plant at full scale (i.e., a scale of several hundred megawatts of plant capacity).

Current Research and Development (R&D) Activities

To address the current lack of demonstrated capabilities for full-scale CO2 capture at power

plants, a number of large-scale demonstration projects at both coal combustion and gasificationbased power plants are planned or underway in the United States and elsewhere. These projects

and the technologies they plan to employ are summarized in CRS Report R41325, Carbon

Capture: A Technology Assessment. Many of these demonstrations are expected to begin

operation in 2014 or 2015. Planned projects for other types of industrial facilities also are

discussed.

Also elaborated in the longer report are the substantial R&D activities underway in the United

States and elsewhere to develop and commercialize lower-cost capture systems with smaller

energy penalties. To characterize the status of capture technologies and the prospects for their

commercial availability, five stages of development are defined: conceptual designs; laboratory or

bench scale; pilot plant scale; full-scale demonstration plants; and commercial processes. The

CRS report reviews current activities at each of these stages for each of the three major capture

routes.

Current R&D activities include development and testing of new or improved solvents that can

lower the cost of current post-combustion and pre-combustion capture, as well as research on a

variety of potential “breakthrough technologies” such as novel solvents, sorbents, membranes,

and oxyfuel systems that hold promise for even lower-cost capture systems. Most of the latter

processes, however, are still in the early stages of research and development (i.e., conceptual

designs and laboratory- or bench-scale processes), so that credible estimates of their performance

and (especially) cost are lacking at this time. Table 1 lists the major approaches being pursued for

post-combustion capture, although many of these approaches apply to pre-combustion and oxycombustion capture as well.

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Carbon Capture Technology Assessment: In Brief

Table 1. Post-Combustion Capture Approaches Being Developed

at Laboratory or Bench Scale

Liquid Solvents

Solid Adsorbents

Membranes

Advanced amines

Supported amines

Polymeric

Potassium carbonate

Carbon-based

Amine-doped

Advanced mixtures

Sodium carbonate

Integrated with absorption

Ionic liquids

Crystalline materials

Biomimetic-based

Source: Edward S. Rubin, Aaron Marks, Hari Mantripragada, Peter Versteeg, and John Kitchin, Carnegie Mellon

University, Department of Engineering and Public Policy.

Processes under development at the more advanced pilot plant scale are, for the most part, new or

improved solvent formulations (such as ammonia and advanced amines) that are undergoing

testing and evaluation. These advanced solvents could be available for commercial use within

several years if subsequent full-scale testing confirms their overall benefit. Pilot-scale oxycombustion processes also are currently being tested and evaluated for planned scale-up, while

two IGCC power plants in Europe are installing pilot plants to evaluate pre-combustion capture

options.

In general, the focus of most current R&D activities is on cost reduction rather than additional

gains in the efficiency of CO2 capture (which can result in cost increases rather than decreases). A

number of R&D programs emphasize the need for lower-cost retrofit technologies suitable for

existing power plants. As a practical matter, however, most technologies being pursued to reduce

capture costs for new plants also apply to existing plants. As the fleet of existing coal-fired power

plants continues to age, the size of the potential U.S. retrofit market for CO2 capture will continue

to shrink, as older plants may not be economic to retrofit (although the situation in other

countries, especially China, may be quite different).

Future Outlook

Whether for new power plants or existing ones, the key questions are the same: When would

advanced CO2 capture systems be available for commercial rollout, and how much cheaper would

they be compared to current technology?

To address the first question, CRS Report R41325, Carbon Capture: A Technology Assessment,

reviews a variety of “technology roadmaps” developed by governmental and private-sector

organizations in the United States and elsewhere. All of these roadmaps anticipate that CO2

capture will be available for commercial deployment at power plants by 2020. Current

commercial technologies like post-combustion amine systems could be available sooner. A

number of roadmaps also project that novel, lower-cost technologies like solid sorbent systems

for post-combustion capture will be commercial in the 2020 time frame. Such projections

acknowledge, however, that this will require aggressive and sustained efforts to advance

promising concepts to commercial reality.

That caveat is strongly supported by a review of experience from other recent R&D programs to

develop lower-cost technologies for post-combustion SO2 and NOx capture at coal-fired power

plants. Those efforts typically took two decades or more to bring new concepts (like combined

SO2 and NOx capture processes) to commercial availability. By then, however, the cost

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Carbon Capture Technology Assessment: In Brief

advantages initially foreseen for these novel systems had largely evaporated in most cases: the

advanced technologies tended to get more expensive as their development progressed (consistent

with “textbook” descriptions of the innovation process), while the cost of formerly “high-cost”

commercial technologies gradually declined over time. The absence of a significant market for

the novel technologies put them at a further disadvantage. This may be similar to the situation for

CO2 capture systems today. Thus, the development of advanced CO2 capture technologies is not

without financial risks.

With regard to future cost reductions, based on past experience, the costs of environmental

technologies that succeed in the marketplace tend to fall over time. For example, after an initial

rise during the early commercialization period, the cost of post-combustion SO2 and NOx capture

systems declined by 50% or more after about two decades of deployment at coal-fired power

plants. This trend is consistent with the “learning curve” behavior seen for many other classes of

technology. It thus appears reasonable to expect a similar trend for future CO2 capture costs once

these technologies become widely deployed. Note, too, that the cost of CO2 capture also depends

on other aspects of power plant design, financing, and operation—not solely on the cost of the

CO2 capture unit. Future improvements in net power plant efficiency, for example, would tend to

lower the unit cost of CO2 capture.

Other cost estimates for advanced CO2 capture systems are based on engineering-economic

analysis of proposed system designs. For example, recent studies by the U.S. Department of

Energy (DOE) foresee the cost of advanced PC and IGCC power plants with CO2 capture falling

by 27% and 31%, respectively, relative to current costs as a result of successful R&D programs.

No estimates are provided, however, as to when the various improvements described are expected

to be commercially available. In general, the farther away a technology is from commercial

reality, the lower its estimated cost tends to be. Thus, there is considerable uncertainty in cost

estimates for technologies that are not yet commercial, especially those that exist only as

conceptual designs.

More reliable estimates of future technology costs typically are linked to projections of their

expected level of commercial deployment in a given time frame (i.e., a measure of their market

size). For power plant technologies like CO2 capture systems, this is commonly expressed as total

installed capacity. However, as with other technologies whose sole purpose is to reduce

environmental emissions, there is no significant market for power plant CO2 capture systems

absent government actions or policies that effectively create such markets—either through

regulations that limit CO2 emissions, or through voluntary incentives such as tax credits or direct

financial subsidies. The technical literature and historical evidence examined in CRS Report

R41325, Carbon Capture: A Technology Assessment, strongly link future cost reductions for CO2

capture systems to their level of commercial deployment. In widely used models based on

empirical “experience curves,” the latter measure serves as a surrogate for the many factors that

influence future technology costs, including the level of R&D expenditures and the new

knowledge gained through learning-by-doing (related to manufacturing) and learning-by-using

(related to technology use).

Based on such models, published estimates project the future cost of electricity from power plants

with CO2 capture to fall by as much as 30% below current values after roughly 100,000

megawatts (MW) of capture plant capacity is installed and operated worldwide. That estimate is

in line with the DOE projects noted above. If achieved, it would represent a significant decrease

from current costs—one that would bring the cost and efficiency of future power plants with CO2

capture close to that of current plants without capture. For reference, it took approximately 20

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Carbon Capture Technology Assessment: In Brief

years following passage of the 1970 Clean Air Act Amendments to achieve a comparable level of

technology deployment for SO2 capture systems at coal-fired power plants.

Uncertainty estimates for these projections, however, indicate that future cost reductions for CO2

capture also could be much smaller than indicated above. Thus, whether future cost reductions

would meet, exceed, or fall short of current estimates will only be known with hindsight.

In the context of this report and CRS Report R41325, Carbon Capture: A Technology Assessment,

the key insight governing prospects for improved carbon capture technology is that achieving

significant cost reductions would require not only a vigorous and sustained level of R&D, but

also a substantial level of commercial deployment. That would necessitate a significant market

for CO2 capture technologies. At present such a market does not exist. While various types of

incentive programs can accelerate the development and deployment of CO2 capture technology,

actions that significantly limit emissions of CO2 to the atmosphere ultimately would be needed to

realize substantial and sustained reductions in the future cost of CO2 capture.

Author Contact Information

(name redacted)

Specialist in Energy and Natural Resources Policy

/redacted/@crs.loc.gov, 7-....

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