Environmental Engineering Reference
In-Depth Information
But there is a big challenge to using fossil fuels for energy. These quantities of coal, oil, and gas aren't
lying around to be plucked. They are
hidden and trapped
underground—sometimes thousands and thou-
sands of feet underground, often in forms, such as being trapped in stone, that are difficult to get out even
if you know where they are.
Fortunately for us, the fossil fuel industry is very, very good at using
technology
to extract these hidden,
trapped, and otherwise useless materials, which no one knew about or cared about through most of human
history, and turning them into the energy of life.
The technical term for fossil fuels is
hydrocarbons,
because they are primarily made of carbon and hy-
drogen atoms. Also, there is some debate over whether all of them come from plants (fossils); some say
that many or most of them come from deep in the Earth, far below where any plants could end up. In either
case, there are astonishing quantities of hydrocarbons. With ever-evolving technology, they give us an un-
paralleled source of concentrated, stored, and scalable energy.
Fossil fuels come in three major forms—coal, oil, and natural gas—with different strengths and weak-
nesses.
COAL
Coal is the world's leading fuel for electricity—producing 41 percent of the world's electricity in
2011—and is expected to become the leading source of energy overall.
3
In the developing world, it has
been the overwhelming choice for every country that has industrialized recently.
Since the 1980s, the world has experienced record increases in coal consumption: in Brazil, by 144 per-
cent; in India, by 425 percent; in China, by 514 percent.
4
It is no coincidence that countries with increased
coal consumption also experience better lives overall—as electricity consumption increases, infant mor-
tality rate decreases rapidly and access to improved drinking water sources increases.
5
The reason coal is particularly well suited for cheap electricity around the world is that it is plentiful,
widely distributed, and relatively easy to extract. Coal is also relatively easy to transport. It exists in a
convenient form, and unlike most mine products, which require you to separate large amounts of material
from the small amount of material you want, coal requires relatively little processing.
But because of its plant origins and underground locations, some of coal's carbon and hydrogen are
bonded to potentially significant quantities of sulfur and nitrogen. When burned, these become sulfur di-
oxide and various nitrogen oxides, which above certain concentrations can be harmful, requiring various
filtration and dilution technologies (more on this in chapter 6). Coal has the highest percentage of carbon
atoms of all the fossil fuels, so when burned, it emits the most carbon dioxide, whose impact we will ex-
amine in chapter 4.
Coal has been used for transportation fuel and was the dominant form of energy for locomotives and
steamships when the steam engine was still the main source of motive power.
6
Eventually the steam en-
gine was supplanted by the much more versatile internal combustion engine, which has nearly eliminated
coal's use as a transportation fuel in favor of oil. Because the fossil fuels' value comes from their being
hydrocarbons—combinations of hydrogen and carbon—each of them can be made to have many of the
propertiesoftheothers,butthattransformation requiresenergyandresources,likeanytransformation, and
