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Coal

Jump to: Coal-based Generation or The Future of Coal

Coal is an abundant, high-energy content, burnable rock, containing organic matter, carbon, and other elements and minerals [1]. Coal is the most abundant fossil fuel in the United States and its usage has accelerated as petroleum and natural gas have become more expensive and scarce [1, 2]. Coal serves as the fuel for the generation of more than half of the electricity in the US every day [1].

There are four distinct types of coal: lignite, sub-bituminous, bituminous, and anthracite. Each type differs in color, density, energy content, current usage, and mined location [1]. The top five coal reserve states are Montana, Illinois, Wyoming, West Virginia, and Kentucky but coal can be found in 38 of the 50 US states [1].

Coal has been utilized in one form or another for centuries and mining coal has become considerably more efficient and advanced over the years. Consider that in 1945, there were over 380,000 coal miners in the US who averaged almost 6 tons of coal production daily. By the 1990s, less than 100,000 miners averaged more than 40 tons daily [1].

The US has more coal reserves than any other country in the world and US coal output is the second highest in the world, after China. US output accounted for about 21% of global production in 2002 [3]. As of 2002, the US had a proved amount of coal in place of approximately 500 billion tons, recoverable reserves of approximately 270 billion tons, and was producing approximately 1.1 billion tons of coal per year [3]. The proved recoverable reserves of approximately 270 billion tons represents about 27% of the global total [3]. The World Energy Council estimates that there may be over 1.1 trillion tons of additional coal in place which, with the right technological advances, may be retrievable in the future [3]. Some estimates predict that global coal reserves can last 2,000 years current consumption rates [2].

Although long-term estimates indicate plentiful coal reserves for hundreds, if not thousands of years to come, physical coal stocks (recovered and utilizable) declined each year between 2002 and 2005, totaling approximately 100 million tons in late 2005 – the lowest end-of-year point since 1997 [4].

Coal-based Generation

A typical coal-based power plant produces energy by first burning coal to heat water in boiler tubes. The water becomes steam and turns a turbine which drives a generator to create electricity [5]. Today’s coal plants are sophisticated machines, with advanced pollution control systems, and ranging in size from less than 50 MW to more than 3,000 MW [5]. The Edison Electric Institute provides a detailed summary on various coal power plant types along with benefits and advancements.

US power plants consume 92% of coal produced in the United States and the remainder is exported [3]. Fifty percent of the electricity generated in the US comes from coal [5]. As of the late 1990s there were about 500 coal-fired power plants in the US. Some of the largest plants can use more than 20,000 tons of coal per day and on average each ton of coal consumed at a power plant generates about 2 MWh of electricity [1].

The Future of Coal

It is estimated that demand for coal will remain strong into the foreseeable future. This is due to a projected increase in use of coal for electricity generation, barriers currently facing the development of alternatives (especially barriers to nuclear development), and the emergence and popularity of “clean coal technologies” [2]. Indeed, there has been much recent progress in innovative technologies aimed at increasing coal efficiency and minimizing harmful emissions [5].

Clean coal technology is a new generation of energy processes that sharply reduce air emissions and other pollutants from coal-burning power plants [6]. The Bush administration’s Clean Coal Power Initiative is providing government co-financing for new coal technologies that can help utilities cut sulfur, nitrogen, and mercury pollutants from power plants by nearly 70% by the year 2018 [6]. Furthermore, clean coal plants have proven to increase coal-to-electricity efficiency, which, in turn reduces greenhouse gas emissions [6].

In 2003, President George W. Bush announced that the US will sponsor a $1 billion, 10-year demonstration project to create FutureGen, the world’s first coal-based, zero-emissions electricity and hydrogen power plant. The prototype plant will establish the technical and economic feasibility of producing electricity and hydrogen from coal, while capturing and sequestering the carbon dioxide generated in the process [7].

Due to FutureGen and other advanced coal projects, coal is likely to remain one of the nation’s most widely-used and lowest-cost electric power sources for the foreseeable future [6].