Clean coal is a term most often used by the media
in news stories that reference
carbon capture and
storage/sequestration (CCS). The phrase "clean coal" is also
referred to as "cleaner coal" in an attempt to mitigate criticism.
These technologies are in development and aim to reduce
CO
2 at coal fired power plants in order to
mitigate climate change.
Scientific consensus on
climate change is that it is caused by human activities, which
increase production of CO
2 and other greenhouse gases.
Carbon capture and storage is intended to reduce emissions from
coal–fired power generation,
which is one of the greatest sources of global warming pollution
contributing more emissions than all automobiles in the United
States. There is no agreement across groups as to when CCS will be
available on a commercial scale. Industry leaders emphasize that
the technology should be available by 2020. Meanwhile, others
question its feasibility in that time frame. The
Intergovernmental
Panel on Climate Change suggests that industrialized or "annexe
1" countries need to reduce greenhouse gas emissions by between 25
and 40% by 2020. No commercial scale coal-fired power plant
currently exists that captures the majority of its emissions.
Clean coal technology
The
US Department of Energy
continues to work with private industry in developing advanced
clean coal technologies. One of the clean coal technologies being
developed is carbon capture and sequestration, which is currently
being tested at existing coal-based plants throughout the world.
Perhaps the most popular example of a coal-based plant using carbon
capture technology is
Vattenfall’s
Schwarze Pumpe plant in Germany Another technology under
development is
Integrated Gasification
Combined Cycle or IGCC.
Other clean coal technologies include those that that dewater low
rank coals. Low rank coals often contain a higher level of moisture
content which contains a lower calorific content per tonne. This
causes a reduced burning efficiency and an increased emissions
output. Reduction of moisture from the coal prior to combustion can
reduce emissions by up to 50 percent.
It has been estimated that commercial-scale clean-coal power
stations (coal-burning power stations with carbon capture and
sequestration) cannot be commercially viable and widely adopted
before 2020 or 2025. This time frame is of concern to
environmentalists because, according to the Stern report, there is
an urgent need to mitigate greenhouse gas emissions and climate
change.
Clean Coal and the environment
According to the
United Nations
Intergovernmental
Panel on Climate Change, the burning of coal, a
fossil fuel, is blamed for
climate change and
global warming. (See the UN
IPCC Fourth Assessment
Report). As 25.5% of the world's electrical generation in 2004
was from coal-fired generation (see
World energy resources
and consumption), reaching the carbon dioxide reduction targets
of the
Kyoto Protocol will require
modifications to how coal is utilized.
Sequestration technology has yet to be tested on a large scale and
may not be safe or successful. Sequestered CO2 may eventually
"leak" up through the ground, may lead to unexpected geological
instability or may cause contamination of aquifers used for
drinking water supplies. There are also concerns that plans to pump
some of the sequestered CO2 into certain oil and gas reserves, to
help make the fuels easier to pump out of the ground, will lead to
increased concentrations of CO2 in potential fuel supplies. This
would have to be removed or released during the refining
process.
Technologies related to reducing the environmental impact of
extracting energy from coal do not address environmental impacts of
coal mining.
Examples of environmental impacts of coal
mining include the Kingston Fossil Plant coal fly ash slurry
spill
.
Byproducts
The byproducts of coal combustion are considerably hazardous to the
environment if not properly contained.
While it is possible to remove most of the sulfur dioxide
(SO
2),
nitrogen oxides
(NO
x) and
particulate matter (PM) emissions from the
coal-burning process, carbon dioxide (CO
2) emissions and
radionuclideswill be more difficult to address.
Coal-fired power plants are the largest aggregate source of
mercury: 50 tons per year come
from coal power plants out of 150 tons emitted nationally in the
USA and 5000 tons globally. In the USA, neither the combustion
products of oil, nor their associated solid or liquid waste
streams, are considered to be major contributors to mercury
pollution.
Potential cost of clean coal
Whether clean coal technology is adopted world wide will …“depend
less on science than on economics. Cleaning coal is very
expensive.”
Projected costs for
carbon
capture and storage (CCS) can be found in that article. Credit
Suisse Group says $15 billion needs to be invested in CCS over the
next 10 years for it to play an important role in climate change.
The
International Energy
Agency says $20 billion is needed. The
Pew Center on Global Climate
Change says the number is as high as $30 billion. Those figures
dwarf the actual investments to date.
In the US, the Bush administration spent about $2.5 billion on
clean coal technology — a
large amount, but far less than what will be needed . CCS
proponents say both the government and the private sector need to
step up their investments.
FutureGen
FutureGen
is a US
government project, announced by President George W. Bush in 2003 to build a near zero-emissions
coal-fueled
power
plant to produce
hydrogen and
electricity while using
carbon capture and storage.
Funding for the plant was withdrawn by the
Department of Energy on 29 January
2008.
Support and criticism
Support
In the United States, clean coal was been mentioned by former
President
George W. Bush on several occasions, including his 2007
State of the Union
Address. Bush's position was that clean coal technologies
should be encouraged as one means to reduce the country's
dependence on foreign oil.
During the 2008 US Presidential campaign, both candidates
John McCain and
Barack
Obama expressed interest in the development of clean coal
technologies as part of an overall comprehensive energy plan. The
development of clean coal also creates the possibility of
international business for the United
States and other world markets.
In 2009, President Obama included $3.4 billion in his stimulus
package for advanced clean coal technologies, including carbon
capture and sequestration demonstration projects.
Current Secretary of State Hillary Clinton has said that “we should
strive to have new electricity generation come from other sources,
such as clean coal and renewables,” and current Energy Secretary
Dr. Steven Chu has said that “It is absolutely worthwhile to invest
in carbon capture and storage,” noting that even if the U.S. and
Europe turned their backs on coal, developing nations like India
and China would not.
In Australia, clean coal is often referred to by
Prime Minister Kevin Rudd as a possible way to reduce greenhouse
gas emissions. (The previous
Prime Minister John Howard has stated that
nuclear power is a better alternative, as
clean coal technology may not prove to be economically
favourable.)
Criticism
Prominent environmentalists, including
Dan
Becker, director of the
Sierra
Club's Global Warming and Energy Program, believe that the term
clean coal is misleading: "There is no such thing as 'clean coal'
and there never will be. It's an
oxymoron".
The Sierra Club's Coal Campaign has launched a site refuting the
clean coal statements and advertising of the coal industry,
[170691].
Complaints focus on the environmental impacts of
coal extraction, high costs to
sequester carbon, and uncertainty
of how to manage end result
pollutants
and
radionuclides.
Critics of the planned power plants assert that there is no such
thing as "clean coal" and that the plant will still release large
amounts of pollutants compared to renewable energy sources such as
wind power and
solar power.
The 2007
Australian of
the Year
, paleontologist and influential environmental
activist Tim Flannery made the
assertion that the concept of clean coal might not be viable for
all geographical locations.
Critics also point out that the continuing construction of
coal-powered plants (whether or not they use carbon sequestration
techniques) encourages unsustainable mining practices for coal,
which can strip away mountains, hillsides, and natural areas. They
also point out that there can be a large amount of energy required
and pollution emitted in transporting the coal to the power plants.
Also,
scrubbers will do nothing to reduce
greenhouse gases:
The Reality Coalition, a nonprofit organization composed of
Alliance for Climate Protection, Sierra Club, National Wildlife
Federation, the Natural Resources Defense Council and the League of
Conservation Voters, ran a series of television commercials in 2008
and 2009. The commercials were highly critical of clean coal,
stating that there are no clean coal power plants in existence in
the U.S and that without capturing CO2 emissions and storing it
safely that it cannot be called clean coal.
Greenpeace is a major opponent of the
concept because they view emissions and wastes as not being avoided
but instead transferred from one
waste
stream to another.
Prior terminology
Clean coal was an
umbrella term used to describe methods that
have been developed to reduce the environmental impact of
coal-based electricity, which accounts for nearly half of the
United States’ electricity supply. These efforts include chemically
washing
minerals and impurities from the
coal,
gasification (see also
IGCC), treating the
flue
gases with
steam to remove
sulfur dioxide,
carbon capture and storage
technologies to capture the
carbon
dioxide from the
flue gas and coal
de-watering technologies to improve the calorific quality and thus
the efficiency of burning coal for energy. These methods and the
technology used are described as clean coal technologies. Figures
from the Environmental Protection Agency show that these
technologies have made today’s coal-based generating fleet 77
percent cleaner on the basis of regulated emissions per unit of
energy produced.
While the term “clean coal” is today commonly used to describe
carbon capture technologies, the earliest use of the term can be
traced back to U.S. Senate Bill 911 in April, 1987 :
“The term clean coal technology means any technology…deployed at a
new or existing facility which will achieve significant reductions
in air emissions of sulfur dioxide or oxides of nitrogen associated
with the utilization of coal in the generation of
electricity.”
It was in the late 1980s and early 1990s that the U.S. Department
of Energy (DOE) conducted a joint program with the industry and
State agencies to demonstrate these technologies large enough for
commercial use. The program, called the Clean Coal Technology &
Clean Coal Power Initiative , has had a number of successes that
have reduced emissions and waste from coal-based electricity
generation
[170692]. Moreover, the Program has met
regulatory challenges by incorporating nitrogen oxide (NOx) control
technologies “into a portfolio of cost-effective regulatory
compliance options for the full range of boiler types.” This
portfolio has positioned the U.S. as a top exporter of clean coal
technologies such as those used for NOx. The DOE continues its
programs and initiatives through regional sequestration
partnerships, a carbon sequestration leadership forum and the
Carbon Sequestration Core Program, a carbon capture and
sequestration research and development program.
According to a report by the assistant secretary for fossil energy
at the U.S. Department of Energy, clean coal technology has paid
measurable dividends. Technological innovation introduced through
the CCT Program now provides consumers cost-effective, clean,
coal-based energy.
Sulfur dioxide (SO
2) and nitrogen dioxide
(NO
2) control technologies emerging from clean coal
technology have moved into the utility and industrial marketplace
and now provide cost-effective regulatory compliance. A new
generation of advanced coal-based power systems has been placed in
commercial service that represents a quantum leap forward in terms
of efficiency and environmental performance. These advanced power
systems projects will provide a springboard for widespread, global
deployment. This in turn will contribute greatly to reductions in
greenhouse gas emissions.
The government and industry officials continue to use the term
"clean coal" to describe technologies designed to enhance both the
efficiency and the environmental acceptability of coal extraction,
preparation and use, however today the term “clean coal technology”
is usually used in reference to
carbon capture and storage, an
advanced process that eliminates carbon dioxide emissions from
coal-based plants and permanently sequesters them.
In the early 20th century, prior to World War II, "clean coal"
(also called "smokeless coal") referred to
anthracite and high-grade
bituminous coal, used for cooking and home
heating.
See also
Notes and references
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