used as a fuel. Some of the chemicals in unprocessed natural gas are poisonous to humans.
Other parts, such as water, make the gas a less useful fuel. The processing removes almost
everything but methane from natural gas. At this point, the gas is ready to be delivered and
used.
Natural gas, often known simply as gas, is delivered to homes for uses such as cooking and
heating. Many ranges and ovens use natural gas as a fuel, and gas-powered furnaces, boilers,
water heaters, and clothes dryers are also common.
Natural gas is a major source of energy for powering gas turbines and steam turbines to
make electricity. When it is used in this way, natural gas works similarly to the way coal
does in producing energy for electricity. Like coal and other fuels, natural gas releases most
of its energy as heat when it burns. The power plant is able to use this heat, either in the
form of hot gases or steam from heated water, to spin turbines. The spinning turbines turn
generators, and the generators create electricity.
Processingandusingnaturalgasdoeshavesomeharmfuleffectsontheenvironment. Natural
gas does burn cleaner than other fossil fuels, meaning that it causes less air pollution. It
also produces less carbon dioxide than the other fossil fuels for the same amount of energy.
Problems with Fossil Fuels
Although they are rich sources of energy, fossil fuels do present many problems. Because
these fuels are nonrenewable resources, their supplies will eventually run out. Safety can
be a problem, too, because these fuels burn so easily. For example, a natural gas leak in a
building or an underground pipe can lead to a deadly explosion.
Using fossil fuels affects the environment in a variety of ways. There are impacts to the
environment when we extract these resources. There are problems that arise because we are
running out of supplies of these resources. Burning these fuels can cause air pollution and
burning them releases carbon dioxide, which is a major factor in global warming (Figure
5.4).
Many of the problems with fossil fuels are worse for coal than for oil or natural gas. Coal
contains less energy for the amount of carbon it contains than oil or gas. As a result, burning
coal releases more carbon dioxide than burning either oil or gas (for the same energy). And
yet coal is the most common fossil fuel and so we continue to burn large amounts of it. Coal
is the biggest contributor to global warming.
Another problem with coal is that it usually contains sulfur. When coal burns, the sulfur
goes into the air as sulfur dioxide. Sulfur dioxide is the main cause of acid rain, which can
be deadly to plants, animals, and whole ecosystems. Burning coal also puts other polluting
chemicals and a large number of small solid ”particulates” into the air. These particles are
dangerous to people, especially those who have an illness, like asthma, that makes breathing
hard for them.