Strategic Technology Research Backgrounder
Carbon Capture and Storage
The Electric Power Research Institute, Inc. (EPRI) conducts research and development relating to the
generation, delivery and use of electricity for the benefit of the public.
With a staff of recognized industry experts, EPRI has established itself as a thought leader in the electric
sector worldwide. The organization is recognized for developing and demonstrating innovative
technologies, analyzing and enhancing current technologies, as well as seeking alternative methods to
produce and deliver electricity.
EPRI’s Technology Innovation (TI) organization has been integral in leading the development of key
technologies that have benefitted the electricity industry in numerous ways. The organization focuses on
stimulating innovation and developing enabling electricity technologies for adoption over a 5-10 year
period, or longer. For instance, EPRI research has lead to recognition of the global impact of mercury, the
development of a high-impact decontamination process and technologies to reduce carbon emissions
from coal generation.
The technology challenges that the electricity industry will face in achieving a low carbon future will
require groundbreaking technology development in a number of strategic areas. EPRI has identified 10
strategic programs that will be the focus of its longer term research efforts from 2009 and beyond. One of
the 10 is described here.
Carbon Capture and Storage
Current Situation
What is the current state of the art?
Although carbon capture and storage (CCS) is widely accepted as the major means of reducing CO2
emissions from the electric power sector, the next generation of low-cost, low-energy CCS technologies is
at least 10 years away from commercial deployment. This is for two reasons. First, low-cost capture
technology is still nascent, with high costs and parasitic loads, and no better technologies are expected to
be commercially available (i.e., with full guarantees) within the next five years. Technologies in the 5-10
year time frame are better, but only at 20-25% parasitic load. Technologies that offer 10-15% parasitic
load remain at laboratory scale, with significant uncertainty regarding their commercial applicability.
A second reason for the 10-20 year time frame to commercially deploy CCS is storage. Although storage
accounts for only 15-30% of the cost of overall CCS, there is little understanding of geological storage
over hundreds or thousands of years. Of the 26 gigatons of CO2 emitted annually from all human
activities, 2 gigatons of CO2 per year would need to be stored around the globe by 2050, assuming a
hypothetical stabilization policy aimed at keeping atmospheric concentrations below 550 parts per million.
The combined weight of the top 100 chemicals emitted worldwide totals approximately 500 Mt/year,
whereas the USA alone emits twelve times that amount of CO2. Several federal programs are underway
now, but results and conclusions from these programs will not be available for at least 5-10 years.
Moreover, significant uncertainty in liability and public acceptance must be addressed before geologic
storage can be fully implemented.
Because of the long time frame required to commercially deploy CCS, the private sector has adopted a
parallel-path approach. This includes large pilot-scale field demonstrations of the most promising CO2
capture technologies currently in the development pipeline as well as through EPRI. This includes the
ongoing search for -- and the support to accelerate the development of -- next generation systems.
Lower-risk technologies are those that involve incremental modifications of known capture chemistry and
application in well-established unit operations to develop an overall CO2 capture process. Examples
include aqueous-based amine or ammonia chemistry in an absorption process. Higher risk technologies
often introduced by startup entrepreneurial companies focus on generating near-term revenues. While
these revenues make the technology attractive to investors, they will result in relatively small CO2
reductions.
EPRI funded a successful project to identify, evaluate, and accelerate postcombustion CO2 capture
technologies. This effort, which is nearing completion, led to the evaluation of over 70 CO2 capture
processes. EPRI reviewed carbon capture technologies worldwide and applied filtering criteria to identify
those best suited for support. Those criteria included assessment of: a technology developer’s interest in
working with EPRI, the potential for EPRI investment to provide significant advancement, the technology’s
suitability for broad application, and its potential to significantly reduce the energy and cost of capture.
Three technologies were selected for acceleration with additional ones planned in the near future – two
involving adsorbents (Univ. Wyoming, ADA-ES), and one involving membranes (MTR). The goal of the
University of Wyoming work is low-cost, moisture-tolerant carbonaceous sorbents. The goal of the MTR
work is novel membrane materials and processes. And the goals of the ADA-ES work are to screen
adsorbents from multiple developers in a test facility, and to develop novel sorbents. Each project is an
early-stage concept with the potential for meaningful reductions in parasitic power relative to near-term
technologies. All three projects are underway with co-funding from federal and state sources, as well as
utility involvement for small-scale testing in later years.
EPRI has also funded a postcombustion capture technology program on the chilled ammonia process.
This laboratory research has created a knowledge base to support the design, implementation, and
optimization of a 1.7-MWe pilot demonstration project at the We Energies Prairie Power Plant. Originally
identified 5-6 years ago, this chilled ammonia process is now undergoing testing at the 1.7-MW plant.
Such advances fit synergistically with EPRI’s existing CCS base programs. These programs are prepared
to adopt the technologies from this program and carry them forward to large-scale demonstrations.
Why is EPRI investing in this area?
Electricity generation accounts for about 40% of total CO2 emissions in the United States. Recent
analyses show that carbon capture and storage could have the largest impact on reducing these
emissions from the electric power sector. More than 80% of these emissions come from coal-fired power
plants. And carbon capture, also called CO2 capture, is the dominant cost in CCS. Near-term CO2 capture
technologies will raise the cost of electricity (COE) produced at these coal plants by 60-90% and impose
a 25-35% parasitic load on the plants. Maintaining coal as a viable source of low-cost electric power
critically will depend on finding more cost-effective ways to capture the CO2 produced. This program
seeks to increase the basic understanding of carbon capture mechanisms and accelerate the
development of technologies offering much lower energy penalties and costs.
The Opportunity
What are the potential superior innovations?
CO2 can be captured by one of two ways: precombustion and postcombustion. Precombustion efforts
have focused on integrated gasification combined-cycle (IGCC) systems, in which coal is processed with
oxygen and steam under pressure to form a synthesis gas—consisting mainly of CO2, carbon monoxide
(CO), and hydrogen—which can be fired directly in a gas turbine. Precombustion CO2 capture builds on
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the advantages of removing CO2 from a concentrated IGCC syngas stream at high temperature and
pressure using solvents or membranes.
Conventional coal plants are faced with the more difficult task of capturing postcombustion CO2 from flue
gas at atmospheric pressure. The concentration of CO2 in flue gas from a pulverized-coal (PC) power
plant is typically less than 15%, with much of the remaining being nitrogen from the air used to support
combustion. Nevertheless, 80–95% of the CO2 can potentially be removed from the flue gas by
postcombustion capture systems. Recent studies suggest that the largest near-term contribution to
reducing the cost of postcombustion capture could come from finding better solvents for absorbing and
desorbing CO2—specifically solvents that could process larger amounts of CO2 for a given mass of
solvent and that would require less energy to drive the desorption process. Alternatively, using pure
oxygen rather than air for combustion eliminates nitrogen from the flue gas and produces a stream that is
over 95% CO2 (dry basis). The latter “oxyfuel combustion” system may reduce the cost of postcombustion
CO2 capture.
How could this research change the industry?
Nowhere are the technical challenges greater, or the stakes higher, than in the development of CCS
technology. Only CCS can reconcile the continued use of enormous U.S. coal resources with the need to
reduce CO2 emissions. The necessary technology advances are now in view. However, a much more
aggressive and accelerated development and demonstration effort is required. Time is short, and the
stakes are high. CCS technology must be ready for widescale commercial deployment for new coalbased generating plants entering service after 2020 and potentially for retrofitting the existing generation
fleet. EPRI research will help address the highest cost portion of this challenge: CO2 capture.
The Program
How are innovations being developed?
This program consists of four projects. In the first project, EPRI is participating in a 10-year consortium at
the Center for Applied Energy Research (CAER) at the University of Kentucky to conduct small-scale
screening tests of in-house and external CO2 capture concepts, on flue gas produced by multiple coals.
Initial CAER processes being tested are a catalyst that accelerates CO2 capture by solvents and a
membrane that enables lower thermal demand for solvent regeneration. In a second project, EPRI is
participating in a consortium effort at Southern Company’s Plant Gaston in system-level demonstrations
for promising CO2 capture technologies at scales beyond laboratory proof-of-concept and up to 2 MW
field pilot, including pre-, post-, and oxy-combustion. The third project includes targeted proof-of-concept
or pilot testing at other locations/labs (including universities) over a five year period. The fourth project
consists of a three-year simulation and modeling internal effort at EPRI to guide process developers and
support internal evaluations.
The first three projects in this program (CAER, Southern Company, and targeted testing at other labs)
address the need for advanced solvents, sorbents, and membranes. Specific technology gaps in
absorption-based capture include development and testing of low-heat of regeneration solvents, thermal
integration with power plants to minimize parasitic load, and reducing capital costs by using kineticallybased capture promoters. In adsorption-based processes, sorbents with higher-capacity and low-energy
regeneration are sought, while still requiring minimal sorbent particle attrition. Membrane-based capture
will focus on development and testing of high-permeability membrane materials, and development of
techniques to minimize membrane fouling by particulates, heavy metals, and other contaminants that
over time may reduce the membrane’s ability to separate CO2 from flue gas.
The fourth project addresses a more fundamental technology gap. That is, target material properties of
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solvents, sorbents, and membranes have not yet been quantified to provide a cost-benefit analysis of
improving the materials that separate CO2. For example, some researchers have argued that increasing
CO2 permeability – even at the cost of decreasing CO2 selectivity – is a better route for reducing the
parasitic load on a power plant. The focus, according to them, should be the development of extremelyhigh permeability membranes as opposed to extremely-selective ones. Such insight comes from detailed
computer simulations of separation processes and systematically varying material properties to
understand its impact on size, parasitic load, and cost of the capture process. In this project, EPRI hopes
to pursue this type of effort not only for membranes, but also for absorption and adsorption.
When will applications occur?
For the reasons discussed above, efficient CO2 capture is at least 10 years away from commercial
deployment. Over the next 10 years, first generation systems will remain expensive but should be
technically viable, while second generation systems with lower energy penalties may not yet be available.
With a major effort, second generation systems can become cost-effective and technically viable by the
end of that time frame. The focus in this program is development and demonstration of these second
generation technologies.
Value
What are anticipated costs and benefits?
Coal currently accounts for about one-half of the electricity generated in the U.S., and is projected by
most analyses to remain the backbone of U.S. electricity supply through 2050. Because coal accounts for
about 80% of CO2 emitted for power generation in the U.S., capture of much of this CO2 is a critical part
of efforts to reduce carbon emissions. And given the high cost today of carbon capture technologies,
reducing this cost would provide a significant benefit to numerous constituents, especially society.
Successful results from this program will not only directly benefit the electric utility industry, but will also
be of global importance.
EPRI research plays an important part in this area, due to the mid-term to long-term nature of the
technology needed. EPRI also plays a key role in bringing together a diverse set of stakeholders, who
separately cannot fully address the CO2 challenge, but together can address it effectively. The reason is
that producing effective CO2 capture solutions requires the coordinated efforts of chemists/materials
scientists to investigate the fundamental science involved, chemical process engineers to define the
separation processes and produce practical systems, and power plant personnel to tailor these systems
to the unique needs of coal power plants.
About EPRI
The Electric Power Research Institute, Inc. (EPRI, www.epri.com) conducts research and development
relating to the generation, delivery and use of electricity for the benefit of the public. An independent,
nonprofit organization, EPRI brings together experts from academia and industry as well as its own
scientists and engineers to help address challenges in electricity generation, delivery and use, including
health, safety and the environment. EPRI's members represent more than 90 percent of the electricity
generated and delivered in the United States, and international participation extends to 40 countries.
EPRI's principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.;
and Lenox, Mass.
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Contact:
Don Kintner
EPRI
Manager, Communications
dkintner@epri.com
704-595-2006
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