Clean Coal

From Global Energy Monitor

This article provides an overview of both the political and the marketing dimensions of clean coal, and the technologies for using coal that have variously been touted as "clean." Each topic is explored in greater depth in separate articles, as are several related topics:

  • Clean Coal Technology - This article assesses progress to date in creating technologies that aimed at eliminating various environmental and health impacts of coal.
  • Clean Coal Marketing Campaign - This article describes the public relations efforts of the coal industry to promote the concept that future coal usage will be safe to the environment and harmless to human health.
  • Clean Coal Subsidies describes federal research and development programs aimed at advancing new coal technologies, as well as subsidies provided to commercial coal operations that meet certain official "clean" criteria even though they may continue to generate major pollution streams.
  • Fly Ash, Coal Waste, and Bottom Ash - These articles describe the kinds of secondary waste streams produced by attempts to create "clean coal."


Inside USA - America's Real Black Gold

The term "clean coal" is both controversial and complex. Controversy arises out of the coal industry's use of the term in its high-profile marketing campaign aimed at convincing the public and politicians that the goal of using coal without damaging the environment and public health is either a current or a foreseeable reality. Coal opponents assert that such usage is not factually based and that its main purpose is to provide public support and political cover for continued expansion of coal use.

Three factors combine to cause additional complexity in the debate:

  • A history of shifting terminology: Over time, the meaning of the term "clean coal" has repeatedly changed, leading to frequent confusion. A hundred years ago the term appeared in newspapers as a synonym for "smokeless" anthracite coal. Today it is frequently used as a shorthand for processes that could allow coal to be used with near-zero greenhouse gas emissions. In the interim it has referred to measures that would reduce various pollutants such as sulfur dioxide and particulates.
  • Gap between old plants, new plants, and next-generation plants: By any measure, the bulk of existing coal plants remain highly polluting. Recently built plants include equipment that reduces most of the sulfur dioxide and nitrous oxide emissions, but they continue to emit large amounts mercury and other toxins, and they do not capture any carbon dioxide. The timeframe for commercial implementation of carbon capture and storage is hotly debated, with estimates ranging from 10 to 30 years in the future.
  • The "whack-a-mole" problem: While the term "clean coal" focuses attention on efforts to reduce to coal's atmospheric impacts, measures to tap down the air impacts of coal often cause other environmental impacts of coal to actually worsen. One example of this perverse phenomenon is the large quantity of toxin-laden sludge produced by sulfur scrubbers. Another is the fact that carbon capture and storage, if implemented, will increase mountaintop removal and other surface mining techniques due to the fact that the energy required by such processes will consume approximately 20-25% of a plant's output.

Shifting terminology

Click here for an archive of clean coal industry advertisements (1921-2012).

Early 20th century: "clean coal" meant "smokeless coal"

Prior to World War II, "clean coal" or "smokeless coal" was a marketing term used to describe anthracite and high-grade bituminous coal used for cooking and home heating.[1]

Late 20th century: "clean coal" meant "coal with lower regulated emissions"

With the arrival of the environmental movement in the late 1960s, the coal industry came under increasing pressure to clean up the myriad of pollutants produced by its mines and plants. Visibility (particulates and nitrous oxides) and acid rain (sulfur dioxide) dominated in the formation of policy established via the 1970 Clean Air Act and subsequent Clean Air Act Amendments in 1977 and 1990, while global warming gases remained unregulated. In response to the new legislation, the coal industry responded with a wide spectrum of technology fixes aimed at lowering "criteria emissions." These included replacement of high-sulfur coal with low-sulfur coal, scrubbers, electrostatic precipitators, coal cleaning techniques, and development of higher efficiency combustion techniques that allowed more electricity to be generated per ton of emissions. By the 1980s, these technologies came to be referred to under the rubric of "clean coal technology," and the term received official recognition in the Department of Energy's Clean Coal Technology Program (1986-1993).[2]

After 2000: "clean coal" starts to mean "zero-emissions coal"

With the arrival of the new millenium and the heightened attention to global warming, the previous usage of "clean coal" to refer to coal with lower regulated emissions was joined by a futuristic new vision, that of "zero-emissions" or "near-zero-emissions coal use. In 2007, President George W. Bush explained the vision as follows:

"One promising solution is advanced clean coal technology. The future of this technology will allow us to trap and store carbon emissions and air pollutants produced by burning coal. Since 2001 the United States has invested more than $2.5 billion to research and develop clean coal. And in partnership with other nations and the private sector we're moving closer to a historic achievement -- producing energy from the world's first zero-emissions coal-fired plant."[3]

Gap between old plants, new plants, and next-generation plants

Older coal plants: highly polluting

  • Fine particles: The fleet of existing coal plants produces large quanitities of fine particles, also known as PM2.5, formed from soot, sulfur dioxide, nitrogen oxides, and metals. These fine particles are estimated to result in 24,000 premature deaths in the United States, averaging 14 lost life-years per person.[4]
  • Sulfur dioxide: Because most existing coal plants pre-date current air pollution laws, current plants emit about 13 million tons per year of sulfur dioxide, approximately a 40% reduction from 1990 levels.[5]
  • Mercury: Coal-fired power plants are the largest source of mercury in the United States, accounting for about 41 percent (48 tons in 1999) of industrial releases.[6][7] According to the Centers for Disease Control and Prevention, eight percent of American women of childbearing age had unsafe levels of mercury in their blood, putting approximately 322,000 newborns at risk of neurological deficits.[7] Mercury exposure also can lead to increase cardiovascular risk in adults.[7]

New plants: cleaner but no carbon controls

As the gas most heavily implicated in global warming, carbon dioxide (CO2) emissions from coal plants are a particular concern. Coal is a much more intensive emitter of CO2 than other fossil fuels. Although coal produces about half of U.S. electricity, it produces about 80 percent of CO2 emissions in the electricity sector and about of overall U.S. CO2 emissions, about the same amount as all transportation sources -- cars, SUVs, trucks, buses, planes, ships, and trains -- combined.[8][9] A 1000 megawatt (MW) coal-fired power plant produces approximately the same amount of global warming as 1.2 million cars.[10] Although new power plants, when equipped with state-of-the-art pollution controls, have significantly less of the type of pollutants that cause acid rain, fine particulate pollution, and mercury toxicity, no currently proposed plants include any equipment to capture emissions of carbon dioxide. Coal-to-liquids technology will have particularly intensive climate effects. According to the Environmental Protection Agency, using liquefied coal as a fuel source would produce 119 percent greater greenhouse gas emissions than using petroleum-based fuel.[11]

Next-generation plants: debating claims of "near-zero-emissions" or "zero-emissions coal"

Ad opposing "clean coal"
"I believe" ad

Climate scientists and environmentalists have criticized carbon capture and storage (CCS), the main enabling technology for zero-emissions coal, as a "pipe dream" that distracted attention and resources from already existing solutions. Dan Becker, director of the Sierra Club's Global Warming and Energy Program, argues that the term clean coal is misleading: "There is no such thing as 'clean coal' and there never will be. It's an oxymoron".[12] The most comprehensive set of arguments in opposition to CCS was advanced by the study "False Hopes: Why Carbon Capture and Storage Won't Save the Climate, published by Greenpeace in May, 2008. "False Hopes" argued as follows:

CCS cannot deliver in time to avoid dangerous climate change. The earliest possibility for deployment of CCS at utility scale is not expected before 2030. To avoid the worst impacts of climate change, global greehouse gas emissions have to start falling after 2015, just seven years away.
CCS wastes energy. The technology uses between 10 and 40% of the energy produced by a power station. Wide scale adoption of CCS is expected to erase the efficiency gains of the last 50 years, and increase resource consumpton by one third.
Storing carbon undedrground is risky. Safe and permanent storage of CO2 cannot be guaranteed. Even very low leakage rates could undermine any climate mitigation efforts.
CCS is expensive. It could lead to a doubling of plant costs, and an electricity price increase of 21-91%. Money spent on CCS will divert investments away from sustainable solutions to climate change.
CCS carries significant liability risks. It poses a threat to health, ecosystems and the climate. It is unclear how severe these risks will be.

Other objections to the notion of "zero-emissions" or "near-zero emissions" coal include the following:

  • Slow penetration. Because CCS cannot be economically retrofitted onto existing power plants, the technology will only be adopted as new power plants are built and old power plants retired. Since coal plants typically last for about 50 years, only about 2% of the fleet is ready for retirement in a given year. Even if CCS did become commercially available between 2020 (Electric Power Research Institute estimate) and 2030 (Greenpeace estimate), it would take several more decades--after 2050--for even half the coal fleet to capture its carbon. But James Hansen and other scientists have said that a phase-out of coal plants that do not sequester their carbon needs to take place by 2030, a full generation earlier.[13]
  • Geographic limitations. The actual degree of penetration of the technology will be further restricted by geographic limitations, since not all power station locations are close enough to geologically suitable storage locations. For example, power producing regions of New South Wales and South Australia that produce about 39% of Australia's CO2 emissions are over 500 km from identified storage locations.[14]
  • CCS fails a life-cycle analysis. Because of their high energy requirements, CCS requires large amounts of additional coal to be mined, and the mining, transport, and usage of the additional coal increases emissions of global warming gases, thereby undermine the benefit of CCS. One study estimated a CCS system that removed 85% to 98% of carbon emissions would actually only reduce greenhouse gas emissions by 67% to 78% due to these additional emissions.[15]
  • Fig leaf. By providing an illusion of safe use, CCS creates an excuse for allowing continued expansion of coal.
  • Diversion of resources. By diverting scare R&D resources, CCS holds up development of cleaner energy sources.

Increased mountaintop removal

The concept of "clean coal" focuses on reducing air pollution. But the increased energy requirements of carbon capture and sequestration (CCS) mean more mining to provide the 10% to 40% energy penalty created by the carbon capture and sequestration process.

Carbon capture and storage makes coal more expensive than wind and solar

Adding carbon and capture technology to new coal plants makes electricity from coal more expensive than energy from solar thermal and wind power, even when "firming costs" are included for alternatives (see table).

Capturing and compressing CO2 requires much energy, significantly raising the running costs of CCS-equipped power plants. In addition there are added investment or capital costs. The process would increase the energy needs of a plant with CCS by about 10 to 40 percent. The costs of storage and other system costs are estimated to increase the costs of energy from a power plant with CCS by 30 to 60 percent, depending on the specific circumstances.

The following table shows cost comparisons published by the California Energy Commission in 2008 for various power-generation technologies, including integrated gasification combined cycle (IGCC) with CCS.

Costs of electricity with and without carbon capture and storage (US cents per kWh - 2008)

Pulverized coal Integrated gasification combined cycle Nuclear Solar thermal Wind
Without capture 10.6 11.5 15.3 12.7 8.9
With capture and storage N/A 17.3 15.3 12.7 8.9
Figures prepared for California Energy Commission by Energy and Environmental Economics, Inc., a consulting firm that prepares studies for utilities, governmental regulators, law firms, and non-profit agencies.[16] These estimates include firming resource costs. Further information can be found at Comparative electrical generation costs.

The cost of CCS depends on the cost of capture and storage which vary according to the method used. Geological storage in saline formations or depleted oil or gas fields typically cost US$0.50–8.00 per tonne of CO2 injected, plus an additional US$0.10–0.30 for monitoring costs. When storage is combined with enhanced oil recovery to extract extra oil from an oil field, the storage could yield net benefits of US$10–16 per tonne of CO2 injected (based on 2003 oil prices). However, as the table above shows, the benefits do not outweigh the extra costs of capture.

Support for development of CCS

The main argument in favor of CCS is the "critical path" argument. Ceding that CCS is not currently able to achieve the "zero-emissions" objective, some environmentalists argue that the emitting plants should be built if they provide partial steps toward enabling CCS technology to move toward commercial maturity. A prominent exponent of this position is John Thompson, director of the Coal Transition Program for the Clean Air Task Force, which has intervened in favor of at least one power plant even though that plant would only capture and store only a fraction of its carbon dioxide emissions. Thompson said,

"Look, we need to move forward and get the infrastructure for carbon capture and sequestration in place now. And we can't look at this from a U.S. perspective only. The largest coal company in the world isn't Peabody Coal any longer; by the end of next year [China's] Shenhua will probably be the world's largest coal producer. We have to get CCS working in this country so that we have a technology that we can provide to China and India. If environmentalists at the grassroots simply want to fight and stop every single coal plant, then IGCC technology will never develop to a workable level."[17]

Clean Coal has been mentioned by George W. Bush on several occasions, including his 2007 State of the Union Address. Bush's position is that clean coal technologies should be encouraged as one means to reduce the country's dependence on foreign oil. Senator Hillary Clinton has also recently said that "we should strive to have new electricity generation come from other sources, such as clean coal and renewables."[18]

In Australia, clean coal is often referred to by Prime Minister Kevin Rudd as a possible way to reduce greenhouse gas emissions.[19] However, in 2009 a government adviser anonymously told a journalist that "Clean coal has become an invitation for ridicule."[20] The previous Prime Minister, John Howard, stated that nuclear power is a better alternative, as clean coal technology may not prove to be economically favorable.[21]

This usage was featured in the literature for such projects as the now defunct FutureGen in the U.S. and the ongoing GreenGen project in China. Zero-emission technology most typically involved the vision of coal gasification, in which pollutants would be separated out of the emissions stream prior to combustion, together with carbon capture and sequestration, in which carbon dioxide would be liquified and stored permanently underground. Although the coal industry employed advertising that focused on this new of clean coal in support of current-generation plants, the Department of Energy's timeline for its Carbon Sequestration Technology Roadmap indicated that even under optimistic assumptions, carbon sequestration would remain primarily in the demonstration stage for at least the coming decade.[22]

Problems with CCS

According to a peer-reviewed study published in the journal of Society of Petroleum Engineers, titled "Sequestering Carbon Dioxide in a Close Underground Volume" the authors argue that past calculations of CCS were widely off, rendering the technology impractical. Writing for Casper, Wyoming's Star-Tribune, report author Prof. Michael Economides explains,

Earlier published reports on the potential for sequestration fail to address the necessity of storing CO2 in a closed system. Our calculations suggest that the volume of liquid or supercritical CO2 to be disposed cannot exceed more than about 1 percent of pore space. This will require from 5 to 20 times more underground reservoir volume than has been envisioned by many, including federal government laboratories, and it renders geologic sequestration of CO2 a profoundly non-feasible option for the management of CO2 emissions.
Injection rates, based on displacement mechanisms from enhanced oil recovery experiences, assuming open aquifer conditions, are totally erroneous because they fail to reconcile the fundamental difference between steady state, where the injection rate is constant, and pseudo-steady state, where the injection rate will undergo exponential decline if the injection pressure exceeds an allowable value.
The implications of our work are profound. They show that models that assume a constant pressure outer boundary for reservoirs intended for CO2 sequestration are missing the critical point that the reservoir pressure will build up under injection at constant rate. Instead of the 1-4 percent of bulk volume storability factor indicated prominently in the literature, which is based on erroneous steady-state modeling, our finding is that CO2 can occupy no more than 1 percent of the pore volume and likely as much as 100 times less.
We related the volume of the reservoir that would be adequate to store CO2 with the need to sustain injectivity. The two are intimately connected. The United States has installed over 800 gigawatts (GW) of CO2 emitting coal and natural gas power plants. In applying this to a commercial power plant of just 500 MW, which by the way produces about 3 million tons per year relentlessly, the findings suggest that for a small number of wells the areal extent of the reservoir would be enormous, the size of a small U.S. state. Conversely, for more moderate size reservoirs, still the size of the U.S.'s largest, Alaska’s Prudhoe Bay reservoir, and with moderate permeability there would be a need for hundreds of wells. Neither of these bode well for geological CO2 sequestration and the work clearly suggests that it is not a practical means to provide any substantive reduction in CO2 emissions.[23]

Opposition to "clean coal"

Sierra Club: "Coal Is Not the Answer"

Complaints focus on the environmental impacts of mountaintop removal mining, the projected high costs of carbon capture and storage, the human health dangers of large, rapid releases of carbon dioxide, the global warming risk posed by small levels leakage over long periods, increases in coal mining needed to run scrubbers as well as carbon capture and storage systems.

Critics of "clean coal" contend that there is no such thing as "clean coal," since even technology projected by 2020 will still release large amounts of pollutants compared to renewable energy sources such as wind, concentrated solar power, photovoltaic power, hydropower, and geothermal power. 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. Opponents note that carbon capture and storage technology has yet to be used or proven on such a large scale and that it may not be successful. There are also concerns that pumping sequestered CO2 into oil and gas wells to help make the fuels easier to pump out of the ground will lead to further consumption of fossil fuels, and CO2 emissions, thus adding to global warming.[24]

Front group launches "Clean Coal Information Campaign"

In 2010, the front group America's Power Army launched a Clean Coal Technology. It Works. campaign aimed at "educating people" at state fairs, festivals, baseball and football games, college campuses, diner and town squares about "clean coal." In September 2010, as part of the campaign, the group announced that mobile classrooms will be added as well. Called “classrooms on wheels,” the goal is to "help educate the public about clean coal technology and its role in providing affordable, reliable electricity, well-paying jobs and a cleaner environment. In the each classroom, visitors will see interactive displays explaining the history and future of clean coal technology. They will learn how clean coal technology has reduced emissions of sulfur dioxide, nitrogen oxide and particulate matter, how utility mercury emissions will be cut, and how carbon capture and storage will reduce emissions of carbon dioxide."

Clean coal in Australian Politics

WWF Australia on clean coal

Australian Greens Senator Christine Milne accused the Climate Institute Australia and WWF Australia of abandoning "any remaining pretence of being part of the mainstream environment movement", by supporting "clean coal" in an alliance with mining companies and unions.[25] [26]

HRL Limited challenged over "clean coal" claims

In July, 2007, the Australian Climate Justice Program, with the support of Greenpeace, lodged a complaint with the Australian Competition and Consumer Commission (ACCC) over HRL Limited’s use of the term "clean coal" in relation to its proposed new brown coal-fired power plant in Victoria.[27]

Clean coal project in China

Peabody and Chinese companies to pursue clean coal project

In January 2011 it was announced the U.S. based Peabody Coal, China Huaneng Group and Calera Corporation agreed to pursue the development of a clean coal project in the Xilinguole Region of Mongolia. The energy project would include a 1200 MW coal-fired power plant. The proposed plant would seek to capture a portion of carbon dioxide (CO2) and convert it into green building materials, advancing carbon capture technology. The plant would be fueled by a 12 million tonne per year surface mine operated by Peabody Coal.

It was stated that China Huaneng would serve as the power plant operator. Calera would use its technology to convert CO2 into solids that can be used as cement building materials. As of 2011, engineering plans were underway, with more announcements to come later in the year.[28]

Clean coal in Turkey

Turkey supported the 2017 [29] and 2018 Clean Coal Summits and Middle East Technical University claims to be a leading university in clean coal technologies research.[30]

Articles and resources

Related articles


  1. "Smokeless Coal,", accessed May 2008.
  2. The 1986-93 Clean Coal Technology Program, Department of Energy website, accessed May 2008
  3. "Bush Addresses Energy Policy, Climate Change," Washington Post, 9/28/07
  4. Dirty Air, Dirty Power: Mortality and Health Damage Due to Air Pollution from Power Plants, Conrad G. Schneider, Abt Associates, June 2004, sponsored by Clean Air Task Force; Synopsis
  5. Sulfur dioxide and coal
  6. Mercury and coal
  7. 7.0 7.1 7.2 “Mercury Emissions from Coal-Fired Power Plants: The Case for Regulatory Action,” Northeast States for Coordinated Air Use Management, October 2003. (PDF File)
  8. Climate impacts of coal plants
  9. U.S. Environmental Protection Agency (EPA), “Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2004,” April 2006.
  10. Barbara Freese and Steve Clemmer, "Gambling with Coal: How New Climate Laws Will Make Future Coal Plants More Expensive," Union of Concerned Scientists, September 2006, page 2.
  11. Testimony of Joseph Romm before Congress, September 5, 2007.
  12. - Coal Position
  13. "Clock running out on irreversible climate change - Part I," James Hansen, Yale Global, April 16, 2008.
  14. Sadler, H, et al., "Geosequestration: What is it and how much can it contribute to a sustainable energy policy for Australia?" The Australia Institute, Anu, 2004, quoted in False Hope: Why carbon capture and storage won't save the climate, Emily Rochon, Greenpeace, May 2008
  15. Peter Viebahn et al, "Comparison of carbon capture and storage with renewable energy technologies regarding structural, economic, and ecological aspects in Germany," International Journal of Greenhouse Gas Control, 2007
  16. E3 Selected Client List accessed 6/08
  17. Ted Nace, "Stopping Coal In Its Tracks," Orion Magazine, Jan/Feb 2008
  18. Remarks of Senator Hillary Rodham Clinton to the Cleantech Venture Forum VIII
  19. Sue Dunlevy, "Rudd's clean coal pledge", The Daily Telegraph, February 26, 2007.
  20. Adam Morton, "Coming clean", The Age, November 4, 2009.
  21. - Interview: John Howard February 11, 2007.
  22. David Sasoon, "DOE Timelines Show "Clean" Coal Will Be a Long Time Comin'," Solve Climate, 2/1/08
  23. "CO2 sequestration isn't practical" Michael Economides, Casper Star-Tribune, February 20, 2010.
  24. ‘Clean coal’ push concerns environmental activists
  25. Abandoning the polluter pays principle, Christine Milne, Greensblog, Tuesday 15 April, 2008
  26. WWF joins world's leading environment proponents in CCS call, WWF Australia press release, Tuesday, 15 April 2008
  27. "HRL Challenged Over 'Clean Coal' Claims," Climate Justice, July 20, 2007.
  28. "China Huaneng, Peabody and Calera to Pursue Clean Coal Project" Marcel Dröttboom Bulk Solids Handling, January 24, 2011.
  29. "International Clean Coal Summit"
  30. "Clean Coal Technologies Workshop and Panel Was Held"

External resources

Wikipedia also has an article on Clean Coal. This article may use content from the Wikipedia article under the terms of the GFDL.