Frequently Asked Questions

What are "fossil fuels" and why are they called that?

The most common fossil fuels are coal, oil (also called petroleum) and natural gas. Some other fuels, like oil shale and peat (a very young form of coal), also are part of the fossil fuel family. These fuels were formed millions of years ago from plants and animals that died and decomposed beneath tons of soil and rock. At the same time (and for millions of years afterward), ancient plants and animals left their outlines in mud which later dried and solidified into rocks. These outlines, along with hardened bone fragments from the prehistoric animals, are called "fossils."

Why did some decaying material become coal while other ancient material became oil and natural gas?

Coal was formed from plant debris while natural gas and oil were formed from tiny organisms that settled to the bottom of ancient seas and rivers. Differences in temperatures and pressures, along with the amount of time the organisms decayed underground, typically determined whether oil or natural gas was formed. Generally, where the underground temperature was hotter or the pressures were the greatest, natural gas formed.

How much buried plant matter did it take to make coal?

It took 10 feet of dead plant material to make 1 foot of coal.

What keeps oil and natural gas from escaping to the surface of the Earth?

Oil and natural gas are often found under rock formations called "caprock" that are dense enough to trap the oil and gas and keep it from seeping to the surface. Some oil and natural gas have been found at the surface of the Earth. Marco Polo, an Italian explorer, wrote of seepages of oil in the Caspian Sea region. The "eternal fires" reported by Plutarich, a Greek historian, in the area of present day Iraq probably were natural gas seepages that had been ignited by lightning.

Why do we need to use fossil fuels for energy?

For two reasons, primarily:

First, the United States has enough fossil fuels - especially coal and natural gas - to provide energy for decades and possibly, for centuries. At the rate we currently use coal, for example, this country has enough to last for more than 250 years. There is enough natural gas to last until well after the year 2060, possibly enough to last for a hundred years or more. There is even a lot of oil left in the ground, despite that the United States produces only half of the oil it uses.

Second, the cost of these fuels is lower than most other energy sources. The cost of energy is a big part of the cost of making many of the products we use every day.

How much of our energy comes from fossil fuels?

More than 85 percent of the energy used by the United States comes from fossil fuels. Oil supplies about 40 percent of our energy, natural gas provides about 25 percent, while coal provides about 20 percent.

What do we use fossil fuels for?

Fossil fuels touch every moment of our lives - when we wake up or sleep, when we eat, when we use our eyes to see, when we play or work, or when we are ill. For example, oil not only can be refined into fuels, such as gasoline, to power engines, it can also be processed into petrochemicals from which plastics, medicines, paints, etc. can be made. The plastic used to make the alarm clocks that wakes us up can come from petrochemicals (chemicals made from "petroleum", another name from oil). The farmer who raises our food depends on fossil fuels like oil and natural gas to make fertilizers (recently, one company has begun making fertilizer from coal). When we read, our eyeglass frames or lenses may be of plastic made from oil. When we listen to a CD player or telephone we are using equipment made from oil and natural gas. The synthetic fibers that are used to make fabrics for our clothes are produced from fossil fuels. Photographic film for our cameras is also made from petroleum as are many medicines.

Even our schools were built using fossil fuels. Coal, for example, may have provided the heat for the ovens that were used to make bricks. Petroleum was probably used for tarring and waterproofing the roof. The heat in our homes or schools may come from natural gas, as does the fuel used for cooking on stoves and in ovens.

Coal is used primarily as a fuel in electric power plants. In fact, more than half of the electricity generated in the United States comes from plants that burn coal. Coal is also used to make a substance called "coke" that is used in making steel and other metals.

For the source of this article, go to the link below.

U.S. Department of Energy