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Although coal is a fossil fuel, it has little in common with oil. Oil is extremely scarce, but coal is relatively plentiful. Some expert analyses predict that global coal reserves could last up to 118 years compared with only 46.2 and 56.8 years for oil and gas reserves.1 While oil is mostly found in unstable parts of the world, coal stocks are widely distributed on every continent and found in abundance within the borders of many of the globe’s largest energy consumers.
Source: http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/coal.html
Over 75 percent of global coal reserves are located in the United States, China, and India, and various estimates hold that the United States has enough coal deposits last for up to 249 years. Recent geological surveys of the U.S. report that actual recoverable reserves may only last for half of the time previously estimated (119 years).2
The world is by no means facing a coal shortage, but armed with this new knowledge, governments cannot be lured into a false sense of security about future energy needs. Coal, like our other fuel resources, is unsustainable at current consumption levels even though it “is easy to access, it’s in politically stable regions, and the technologies exist to eradicate environmental impacts.”3
While coal has long been an important element of the global energy mix, the great debate in recent years has focused on its future role as the nations of the world attempt to curb their harmful emissions and wean themselves off fossil fuels. One coal-fired electricity plant, for example, provides enough power for 500,000 homes but also releases as much pollution as 750,000 cars. 4
The coal industry has been revitalized in recent years by U.S. Presidents George W. Bush and Barack Obama, who have embraced so-called “clean coal” technologies as a way to harness an available resource in an environmentally sustainable way. In the United States, at least, Obama’s energy secretary has pushed for renewed investment in the project FutureGen to focus on the creation of the first “zero-emission” coal plant.5
Clean Coal
Clean coal technology is a broad term used to describe a series of processes that remove most of the pollutants when coal is burned, thus making it a more environmentally friendly energy source. There are three primary processes covered under the heading of clean coal: the integrated gasification combined cycle (IGCC), carbon capture, and carbon sequestration.
During the IGCC, coal is crushed and mixed with steam to produce a combustible fluid that is clean of many pollutants such as sulfur and mercury. When this fluid is used to make electricity, which it does far more efficiently than traditional coal-fired turbines, carbon dioxide is released as a byproduct and filtered out for later disposal.6
Source: http://www.fossil.energy.gov/programs/powersystems/gasification/howgasificationworks.html
An alternative to IGCC is carbon capture, a method by which normal coal-fired plants are retrofitted with special absorbers that soak up carbon dioxide for subsequent storage. Various capture techniques can also be used when oil or natural gas is initially extracted from the ground. At that stage, huge amounts of carbon dioxide, which form “a proportion of the fossil fuel in its natural state,” are released into the atmosphere. 7 The extraction process is itself one of the major sources of greenhouse gas emissions.
Carbon Sequestration
Once carbon dioxide has been isolated and contained using IGCC or another capture method, it is then converted into a “highly concentrated stream” or “‘supercritical’ state between a liquid and a gas” and stored deep underground. Typically, these streams are pumped into the ocean floor or into old oil or gas reservoirs. Sites capable of storing carbon dioxide in this form must be “deep, porous…covered by a layer of impermeable rock to prevent leakage.”
Source: http://www.epa.gov/climatechange/emissions/co2_geosequest.html
Some fear that earthquakes or other geological disturbances could destabilize the storage areas. 8 While leakages could have dire consequences for the environment, there is no way to judge what the level of risk is with any certainty.
Many supporters of renewable energy sources argue that clean coal and carbon sequestration technologies, while sounding promising, are untested and have limited potential in the near term. In August 2010 the Obama Administration announced it would refit an existing coal plant in Illinois into a plant that could capture most carbon dioxide emissions through oxy-combustion technology. Changing an existing plant is cheaper than the original FutureGen plan to build an original plant. Many hope that more than 500 other coal plants in the country will undergo a similar facelift.
Some critics feel the idea of clean coal is a “smokescreen, since it’s not intended to bring technology to the market at the pace required to deal with the problem.” It is estimated that retrofitting old coal-fired plants or building new ones equipped with clean coal technology as it currently would add anywhere from 30-80 percent to the cost of electricity. 9 The future of clean coal will ultimately hinge on whether these costs will prove acceptable to power utilities and consumers.New developments must be made on current technology to bring the extra costs down to 35 percent at most and ensure a higher probability of success for clean coal.10
1 Statistical Review of World Energy 2011
5 Garber (To read more about the FutureGen Project see: http://www.futuregenalliance.org/.)
6 Friedman and Homer-Dixon; Harvey, “Science Rises to the Challenge”
7 Harvey, “Science Rises to the Challenge”
8 ibid.; Friedman and Homer-Dixon
9 DOE “Retrofitting the Existing Coal Fleet.”
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