Coal pollution mitigation

Regulations

Since the 1970s, various policy and regulatory measures have driven coal pollution mitigation. As demand has increased so costs have fallen and performance has improved.

The widespread deployment of pollution-control equipment to reduce sulphur dioxide, NO_x and dust emissions is just one example that brought cleaner air to many countries. The desire to tackle rising CO₂ emissions to address climate change later introduced Carbon Capture and Storage (CCS).

Within the United States, Carbon Capture and Storage technologies, also sometimes referred to as carbon capture and sequestration, are mainly being developed in response to regulations by the Environmental Protection Agency—most notably the Clean Air Act—and in anticipation of legislation that seeks to mitigate climate change.

Loan guarantees and tax incentives have a long history of use in Australia, EU countries and the US to encourage the introduction of coal pollution mitigation and other technologies to reduce environmental impact.

Greenhouse gasses

According to the United Nations Intergovernmental Panel on Climate Change, the burning of coal, a fossil fuel, is a significant contributor to global warming. (See the UN IPCC Fourth Assessment Report). For 1 ton of coal burned, 2.86 tons of carbon dioxide is created.

Carbon 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.

As 25.5% of the world's electrical generation in 2004 was from coal-fired generation (see world energy consumption), reaching the carbon dioxide reduction targets of the Kyoto Protocol will require modifications to how coal is used.

By-products

It is possible to remove most of the sulfur dioxide (SO₂), nitrogen oxides (NO_x), and particulate matter (PM) emissions from the coal-burning process, but CO₂ emissions and the trace amounts of radionuclides are more difficult to remove.

Coal-fired power plants are the largest aggregate source of the toxic heavy metal mercury: 50 tons per year come from coal power plants out of 150 tons emitted nationally in the USA and 5000 tons globally. However, according to the United States Geological Survey, the trace amounts of mercury in coal by-products do not pose a threat to public health. A study in 2013 found that Mercury found in the fish in the Pacific Ocean could possibly be linked to coal-fired plants in Asia.

Potential financial impact

Whether carbon capture and storage technology is adopted worldwide will “…depend less on science than on economics. Cleaning coal is very expensive.”

Cost of converting a single coal-fired power plant

Conversion of a conventional coal-fired power plant is done by injecting the CO₂ into ammonium carbonate after which it is then transported and deposited underground (preferably in soil beneath the sea). This injection process however is by far the most expensive. Besides the cost of the equipment and the ammonium carbonate, the coal-fired power plant also needs to use 30% of its generated heat to do the injection (parasitic load). A test-setup has been done in the American Electric Power Mountaineer coal-burning power plant.

One solution to reduce this thermal loss/parasitic load is to burn the pulverised load with pure oxygen instead of air.

Cost implications for new coal-fired power plants

Newly built coal-fired power plants can be made to immediately use gasification of the coal prior to combustion. This makes it much easier to separate off the CO₂ from the exhaust fumes, making the process cheaper. This gasification process is done in new coal-burning power plants such as the coal-burning power plant at Tianjin, called "GreenGen".

Costs for US-wide conversion

The projected nationwide costs for the implementing of carbon capture and storage (CCS) in coal-fired power plants in the USA (presumably using a conventional tactic, see above) can be found in the Wall Street Journal 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 a range of mitigation technologies — a large amount, but far less than the amounts previously suggested. CCS proponents say both the government and the private sector need to step up their investments.

United States

In the United States, "clean coal" was mentioned by former President George W. Bush on several occasions, including his 2007 State of the Union Address. Bush's position was that carbon capture and storage technologies should be encouraged as one means to reduce the country's dependence on foreign oil.

During the US Presidential campaign for 2008, both candidates John McCain and Barack Obama expressed interest in the development of CCS technologies as part of an overall comprehensive energy plan. The development of pollution mitigation technologies could also create export business for the United States or any other country working on it.

The American Reinvestment and Recovery Act, signed in 2009 by President Obama, allocated $3.4 billion for advanced carbon capture and storage technologies, including demonstration projects.

Former 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 former 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 likely not.

During the first 2012 United States presidential election debate, Mitt Romney expressed his support for clean coal, and claimed that current federal policies were hampering the coal industry.

Australia

In Australia, carbon capture and storage was often referred to by then Prime Minister Kevin Rudd as a possible way to reduce greenhouse gas emissions. (The previous Prime Minister John Howard had stated that nuclear power was a better alternative, as CCS technology may not prove to be economically feasible.)

Japan

Following the catastrophic failure of the Fukushima I Nuclear Power Plant in Japan that resulted from the 2011 Tōhoku earthquake and tsunami, and the subsequent widespread public opposition against nuclear power, high energy, lower emission (HELE) coal power plants were increasingly favored by the Shinzō Abe-led government to recoup lost energy capacity from the partial shutdown of nuclear power plants in Japan and to replace aging coal and oil-fired power plants, while meeting 2030 emission targets of the Paris Agreement. 45 HELE power plants have been planned, purportedly to employ integrated gasification fuel cell cycle, a further development of integrated gasification combined cycle.

Japan had adopted prior pilot projects on IGCC coal power plants in the early-1990s and late-2000s.

Criticism of the approach

Environmentalists such as Dan Becker, director of the Sierra Club's Global Warming and Energy Program, believes 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.

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. In reference to sequestration of carbon, concerns exist about whether geologic storage of CO₂ in reservoirs, aquifers, etc., is indefinite/permanent.

The palaeontologist 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 believe 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.

The Reality Coalition, a US non-profit climate organization composed of the Alliance for Climate Protection, the Sierra Club, the 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 attempts to mitigate coal's pollution, stating 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. According to Greenpeace USA's Executive Director Phil Radford speaking in 2012, "even the industry figures it will take 10 or 20 years to arrive, and we need solutions sooner than that. We need to scale up renewable energy; “clean coal” is a distraction from that."

Prior terminology

The industry term "clean coal" is increasingly pushed in reference to carbon capture and storage, an advanced theoretical process that would eliminate or significantly reduces carbon dioxide emissions from coal-based plants and permanently sequesters them. More generally, the term has been found in modern usage to describe technologies designed to enhance both the efficiency and the environmental acceptability of coal extraction, preparation, and use.

U.S. Senate Bill 911 in April, 1987, defined clean coal technology as follows:

"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."

Before being adopted in this fashion, historically "clean coal" was used to refer to clean-burning coal with low levels of impurities, though this term faded after domestic use of coal dropped. The term appeared in a speech to mine workers in 1918, when clean coal meant coal that was "free of dirt and impurities". In the early 20th century, prior to World War II, clean coal (also called "smokeless coal") generally referred to anthracite and high-grade bituminous coal, used for cooking and home heating.