The world depends on coal for most of its electricity production.
Simply put, coal equals energy. Energy is defined as the capacity to do work; like all other living things, we humans need it, in a biological sense, to survive. But we also need it to run our societies: to heat and cool our homes; operate our cell phones, lamps, and laptops; fuel our cars; and power our industries. Most of our energy comes from fossil fuels—nonrenewable carbon-based resources, namely coal, oil, and natural gas—that were formed over millions of years from the remains of dead organisms.
energy
The capacity to do work.
fossil fuels
Nonrenewable resources like coal, oil, and natural gas that were formed over millions of years from the remains of dead organisms.
Worldwide, we used more than 7.5 billion metric tons (8.3 billion U.S. tons) of coal in 2012, the vast majority of it to generate electricity. Electricity is a natural form of energy (lightning and nerve impulses are electrical) that we have learned to create on demand; we produce it in a central location and send it out via transmission lines to where we want it to go. More than 40% of electricity generation worldwide, and 39% in the United States, involves burning coal. (Americans especially love their electricity: In 2013, we used 19.5% of all the kilowatt-hours generated in the world; only China surpassed the United States, using 22%.)
electricity
The flow of electrons (negatively charged subatomic particles) through a conductive material (such as wire).
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KEY CONCEPT 18.1
Coal is the leading fuel used for electricity production. It is burned to heat water to produce steam; the steam turns a turbine connected to a generator, producing electricity.
Coal-fired power plants work by feeding pulverized coal into a furnace to generate heat, which then powers a system that produces electricity. It takes roughly 0.5 kilogram (1 pound) of coal to generate 1 kilowatt-hour (kWh) of electricity; that’s enough to run ten 100-watt incandescent light bulbs for an hour, an energy-efficient refrigerator for 20 hours, or an older, less efficient refrigerator for 7 hours. The average U.S. family of four uses about 11,000 kWh of electricity per year. That comes out to around 1,375 kilograms (3,000 pounds) per person per year.
So, how does coal stack up against other fossil fuel energy sources? On one hand, it produces more air pollution than any other fossil fuel. On the other, it is safer to ship, cheaper to extract, and in the United States at least, more abundant by far. In fact, the United States has 10 times more coal than it does oil and natural gas combined; in 2012 alone, we mined more than 930 million metric tons (1.0 billion U.S. tons). Most of it came from Wyoming, which leads the nation as a coal producer, and the Appalachian mountains, which follow behind as a close second. While we exported some of that yield, the vast majority was used to power American households and businesses. INFOGRAPHIC 18.1
HOW IT WORKS: ELECTRICITY PRODUCTION FROM COAL
The most common way to generate electricity is to heat water to produce steam; the flow of steam turns a turbine inside a generator to produce electricity. This schematic shows TVA’s coal-fired Kingston plant in Tennessee, which generates 10 billion kilowatt-hours a year by burning 13,000 metric tons of coal a day, supplying electricity to almost 700,000 homes.
What other methods could be used to spin a turbine and generate electricity?
Burning any fuel to heat the water and produce steam would turn the turbine; other ways to heat the water include nuclear reactions or naturally heated water such as in hot springs or geothermal sources. Physically spinning the turbine can be done with wind, falling water, or the labor of animals (even a person on a bicycle could turn it).
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In terms of net energy, or energy return on energy investment (EROEI)—a metric that allows us to compare the amount of energy we get from any individual source to the amount we must expend to obtain, process, and ship it—coal is neither the best nor the worst. In terms of electricity production, it has an EROEI of about 18:1 (18 units of energy produced for every 1 unit consumed), compared to 7:1 for natural gas and 5:1 for nuclear power. Wind has a better EROEI, at 20:1, and hydroelectric has the best EROEI, at 40:1.
energy return on energy investment (EROEI)
A measure of the net energy from an energy source (the energy in the source minus the energy required to get it, process it, ship it, and then use it).
There can be no denying the blessings of coal: This sticky black rock has powered several waves of industrialization—first in Great Britain and the United States, now in China—and in so doing has shaped and reshaped the world as we know it. But as time marches on, the costs of those blessings have become all too apparent. They include an ever-growing list of health impacts—from birth defects to black lung disease—and an equally lengthy roster of environmental costs—not only the destruction of Appalachia, but also the pollution of Earth’s atmosphere with CO2 and other greenhouse gases. (See Chapter 21 for more on greenhouse gases and climate change.)
This litany of paradoxes has given rise to a deep national ambivalence. While we are consuming more electricity, and burning more coal, than at any other time in our history, applications for new coal-fired power plants have been rejected left and right in recent years by determined citizens and local governments from Maryland to Minnesota. “We’re caught in a catch-22,” says Scott Eggerud, a forest manager with West Virginia’s Department of Environmental Protection. “On one hand, it’s like we need the stuff to live; on the other hand, we see that it’s kind of killing us.” Nowhere is this catch-22 more pronounced than in the foothills of central and southern Appalachia.