 Clean coal is an umbrella term used in the promotion of the use of coal as an energy source by emphasizing methods being developed to reduce its environmental impact. 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, and carbon capture and storage technologies to capture the carbon dioxide from the flue gas. These methods and the technology used are described as clean coal technology. Major politicians and the coal industry use the term "clean coal" to describe technologies designed to enhance both the efficiency and the environmental acceptability of coal extraction, preparation and use,[1] with no specific quantitative limits on any emissions, particularly carbon dioxide.
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.[2] 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.
The concept of clean coal is said to be a solution to climate change and global warming by coal industry groups, while environmental groups maintain that it is greenwash, a public relations tactic that presents coal as having the potential to be an environmentally acceptable option. Greenpeace[3] is a major opponent of the concept because emissions and wastes are not avoided, but are transferred from one waste stream to another
Byproducts
The byproducts of coal combustion are very hazardous to the environment if not properly contained. This is Clean Coal's largest challenge, both from the practical and public relations perspectives.
While it is possible to remove most of the sulfur dioxide (SO2), nitrogen oxidesparticulate (PM) emissions from the coal-burning process, carbon dioxide (CO2) emissions and radionuclides [10] will be more difficult to address. Technologies do exist to capture and store CO2, but they have not yet been utilized on a large-scale commercial basis due to the high economic costs.[11] (NOx) and
In terms of mercury, coal-fired power plants are the largest aggregate source: 50 tons/year come from coal power plants out of 150 tons emitted nationally in the USA and 5000 tons globally.[12] In the USA, neither the combustion products of oil[13], nor their associated solid or liquid waste streams[14], are considered to be major contributors to mercury pollution.[15]
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Support and Criticism
In the United States, Clean Coal has been mentioned by United States President 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."[20] The US Department of Energy is working with private industry in developing clean coal technologies.[21] One of the clean coal technologies being developed is carbon sequestration, capturing carbon dioxide and eliminating or slowing its release back into the atmosphere. Another technology under development is Integrated Gasification Combined Cycle or IGCC. [22] 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.[23] The development of clean coal also creates the possibility of international business for the United States and other world markets.[24]
In Australia, clean coal is often referred to by Prime Minister Kevin Rudd as a possible way to reduce greenhouse gas emissions.[25] (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 favorable.[26])
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Criticism
Greenpeace has released a report titled False Hope, Why carbon capture and storage won’t save the climate. The report lists five key reasons that carbon capture is not a viable solution. [27]
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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 greenhouse 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 consumption by one third.
Storing carbon underground 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.
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—Greenpeac
See Wikipedia, Clean coal technology, http://en.wikipedia.org/wiki/Clean_coal_technology (as of Nov. 7, 2008, 09:19 GMT).
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