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FORMATION OF FUELS
Fossil fuels began to form hundreds of millions of years ago, even before the time of the dinosaurs! These fuels formed during the Carboniferous Period that occurred from about 354 to 290 million years ago. At that time, the land was covered with swamps filled with huge trees and ferns. As these plants died, they sank to the bottom of the swamps and formed layers of a spongy material called peat. Over many hundreds of years, the peat was covered by layers of sand, clay, and rock. The pressure of these layers dried out the peat and, over millions of years, it turned into solid coal. |
Video: Carboniferous Period
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Around this same time, the ancient oceans began to be filled with small creatures called diatoms. They are only the size of a pinhead but they have the ability to convert sunlight directly into stored chemical energy (just like a plant!). When the ancient diatoms died and fell to the sea floor, they were buried under sediment and rock. Under great pressure and heat, the diatoms eventually became deposits of oil and natural gas.
COAL
Coal is a hard, black, rock-like substance. It is made up of carbon, hydrogen, oxygen, nitrogen and varying amounts of sulfur. Some believe coal has been used for heating since the days of cave men, but the earliest known use of coal was in China where it may have been used to heat copper ore as early as 3,000 years ago.
In the 1700s, the English found that coal could produce a fuel that burned cleaner and hotter than wood charcoal. However, it was the overwhelming need for energy to fuel the Industrial Revolution that finally gave coal an opportunity to become a dominate energy supplier. During the first half of the 1800s, the Industrial Revolution spread to the United States. Steamships and steam-powered railroads were becoming the chief forms of transportation, and they used coal to fuel their boilers.
America has more coal than any other fossil fuel. The United States also has more coal reserves than any other single country in the world. Coal is mined out of the ground and then shipped by train, boat, and even in pipelines. In pipelines, the coal is ground up and mixed with water to make a slurry.
Now, coal is used primarily in the United States to generate electricity. In fact, it is burned in power plants to produce nearly half of the electricity we use. We all use coal every day. A stove uses about half a ton of coal a year. A water heater uses about two tons of coal a year. And a refrigerator, that's another half-ton a year. Even though you may never see coal, you use several tons of it every year!
Coal Problems...
Trapped inside coal are traces of impurities like sulfur and nitrogen, along with many small, polluting particles that do not burn. When coal burns, all of these impurities are released into the air. While floating in the air, these substances can combine with water and fall to earth as sulfuric and nitric acid - scientists call it "acid rain." This is a problem for our environment.
Like all fossil fuels, coal is formed out of carbon. All living things are made up of carbon. But when coal burns, its carbon combines with oxygen in the air and forms carbon dioxide. Carbon dioxide is a colorless, odorless gas, but in the atmosphere, it can trap the earth's heat. Many scientists believe this is causing the earth's temperature to rise, and this warming could be altering the earth's climate. This is another environmental problem.
In the last 20 years, scientists have developed ways to capture the pollutants trapped in coal before the impurities can escape into the atmosphere. Today, we have technology that can filter out 99 percent of the tiny, polluting particles and remove more than 95 percent of the acid rain pollutants in coal. We also have new technologies that cut back on the release of carbon dioxide by burning coal more efficiently. Many of these technologies belong to a family of energy systems called "clean coal technologies." The U.S. Government has invested more than $3 billion in developing and testing these processes. This technology does help our environment, but what if this money would have been directed towards renewable forms of energy (wind, solar, and hydroelectric) instead?
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OIL
Petroleum, or Crude Oil, is liquid mixture of fuels and it can range in color from yellow to black. It has been used for more than 5,000 years. The ancient Egyptians used oil to treat wounds and Native Americans used oil as medicine and to make canoes waterproof. Petroleum is now important to society due to the need for engine fuels, plastics, fertilizers, and adhesives.
When petroleum first came into use, most oil came from coal or by skimming it off the top of lakes. Then, on August 27, 1859, Edwin L. Drake struck liquid oil at his well near Titusville, Pennsylvania. He found oil under ground and devised a way to pump it to the surface. This paved the way for oil drilling around the globe.
Crude oil is currently produced in 31 states and U.S. coastal waters but the majority of oil production comes from Texas, North Dakota, California, Alaska, and Oklahoma.
Petroleum appears to be a liquid but it is actually a mixture of solid, liquid, and gaseous fuels. The mixture of hydrocarbons must be boiled in order to separate and purify it for specific uses. This process is called distillation and it is completed in oil refineries. In the distillation towers, the heavy solids present in crude oil stay at the bottom while the lighter gases rise to the top.
Once crude oil is refined, it can be used for gasoline, jet fuel, diesel, propane, plastics, and other chemicals. It is estimated that the world consumes about 90 million barrels of oil each day.
Oil Problems...
Just like coal, oil is a carbon-based fuel which produces carbon dioxide when it is burned. This greenhouse gas traps heat in our atmosphere so burning oil products can increase temperatures around the globe. Other pollutants are also released into the atmosphere whenever petroleum products are burned.
Oil is also used to make plastics which take hundreds of years to decompose. Due to their long chains of carbon atoms, plastics do not break down over time and are now filling our landfills and natural landscapes. A recent study estimates that 270,000 tons of plastic currently float in our oceans.
The most obvious problem with petroleum is oil spills from drilling rigs and oil tankers. These spills permanently change the local ecosystem and its wildlife. Oil destroys the insulating ability of furry mammals, such as sea otters, and the water repellency of bird feathers. Without the ability to repel water and insulate from the cold water, birds and mammals die from hypothermia. |
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NATURAL GAS
Sometime around 6,000 years ago, the first discoveries of natural gas seeps were made in Iran. The gas seeps were probably first ignited by lightning. Natural gas is mostly made up of a gas called methane which is composed of carbon bonded to four hydrogen atoms. This gas is highly flammable! Natural gas and petroleum are often found together since the same ancient sea creatures formed both fossil fuels.
For most of the 1800s, natural gas was used almost exclusively as a fuel for lamps. Because there were no pipelines to bring gas into individual homes, most of the gas went to light city streets. After the 1890s, however, many cities began converting their street lamps to electricity. Gas producers began looking for new markets for their product.
It took the construction of pipelines to bring natural gas to new markets. Although one of the first lengthy pipelines was built in 1891 (it was 120 miles long and carried gas from fields in central Indiana to Chicago) there were very few pipelines built until after World War II in the 1940s. Improvements in metals, welding techniques and pipe making during the War made pipeline construction more economically attractive. After World War II, the nation began building its pipeline network. Throughout the 1950s and 1960s, thousands of miles of pipeline were constructed throughout the United States. Today, the U.S. pipeline network, laid end-to-end, would stretch to the moon and back twice.
Natural gas usually has no odor and is colorless. Before it is sent to the pipelines and storage tanks, it is mixed with a chemical that gives a strong odor that makes it easy to smell if there is a leak.
Natural gas provides one-fifth of all the energy used in the United States. It is especially important in homes, where it supplies nearly half of all the energy used for cooking, heating, and for fueling other types of home appliances. The United States is looking for more ways to use gas, largely because it is easy to pipe from one location to another and because it burns more cleanly than coal and oil.
Natural Gas Problems... Just like all fossil fuels, natural gas is burned and releases carbon dioxide in the air. In addition, some of the methane is also released to the atmosphere during extraction and distribution of the natural gas. Just like the carbon dioxide, methane is a greenhouse gas that traps heat in the earth's atmosphere. This adds to the problem of global climate change. Natural gas is found deep below the earth's surface and much of the "easy to get" gas has already been retrieved. Current methods for extracting methane involve "fracking" or fracturing the shale rock that contains the gas. This fracking involves drilling into the shale and pumping it full of a mixture of water, sand, and harmful chemicals. This causes the rock to crack and the natural gas to be released. The long-term environmental impacts of this process are unknown but current reports of polluted drinking water and frequent earthquakes have many worried. |
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More Fossil Fuel Videos
PRACTICE:
Match each of the following with the proper fossil fuel(s):
Answers are shown at the bottom of the page.
Match each of the following with the proper fossil fuel(s):
- Transported on trains
- Formed from plants in ancient swamps
- Must be refined to separate it before use
- Formed from plants and animals in ancient oceans
- Often travels on large ocean tankers
- Burned to release chemical potential energy
- Primary fuel used to create electricity in USA
- Give off greenhouse gases and pollutants when burned
- Always travels through pipelines
- Formed hundreds of millions of years ago
Answers are shown at the bottom of the page.
ASSESS:
The Learning Targets listed at the top of this page will be assessed with an open notes quiz.
The Learning Targets listed at the top of this page will be assessed with an open notes quiz.
Resources:
U.S. Department of Energy
Energy Story
Answers to Practice:
U.S. Department of Energy
Energy Story
Answers to Practice:
- Coal
- Coal
- Oil
- Oil and Natural Gas
- Oil
- Coal, Oil, and Natural Gas
- Coal
- Coal, Oil, and Natural Gas
- Natural Gas
- Coal, Oil, and Natural Gas