Where Fossil Fuels Come From?

There are three major forms of fossil fuels: coal, oil and natural gas. All three were formed many hundreds of millions of years ago before the time of the dinosaurs - hence the name fossil fuels. The age they were formed is called the Carboniferous Period. It was part of the Paleozoic Era. "Carboniferous" gets its name from carbon, the basic element in coal and other fossil fuels.

The Carboniferous Period occurred from about 360 to 286 million years ago. At the time, the land was covered with swamps filled with huge trees, ferns and other large leafy plants, similar to the picture above. The water and seas were filled with algae - the green stuff that forms on a stagnant pool of water. Algae is actually millions of very small plants. Some deposits of coal can be found during the time of the dinosaurs. For example, thin carbon layers can be found during the late Cretaceous Period (65 million years ago) - the time of Tyrannosaurus Rex. But the main deposits of fossil fuels are from the Carboniferous Period. As the trees and plants died, they sank to the bottom of the swamps of oceans. They formed layers of a spongy material call peat. Over many hundreds of years, the peat was covered by sand and clay and other minerals, which turned into a type of rock called sedimentary. More and more rock piled on top of more rock, and it weighed more and more. It began to press down on the peat. The peat was squeezed and squeezed until the water came out of it and it eventually, over millions of years, it turned into coal, oil or petroleum, and natural gas.

Coal

Coal is a hard, black colored rock-like substance. It is made up of carbon, hydrogen, oxygen, nitrogen and varying amounts of sulphur. There are three main types of coal - anthracite, bituminous and lignite. Anthracite coal is the hardest and has more carbon, which gives it a higher energy content. Lignite is the softest and is low in carbon but high in hydrogen and oxygen content.Ê Bituminous is in between. Today, the precursor to coal - peat - is still found in many countries and is also used as an energy source. The earliest known use of coal was in China. Coal from the Fu-shun mine in northeastern China may have been used to smelt copper as early as 3,000 years ago. The Chinese thought coal was a stone that could burn.

Coal is found in many of the lower 48 states of U.S. and throughout the rest of the world. Coal is mined out of the ground using various methods. Some coal mines are dug by sinking vertical or horizontal shafts deep under ground, and coal miners travel by elevators or trains deep under ground to dig the coal. Other coal is mined in strip mines where huge steam shovels strip away the top layers above the coal. The layers are then restored after the coal is taken away. The coal is then shipped by train and boats and even in pipelines. In pipelines, the coal is ground up and mixed with water to make what's called a slurry. This is then pumped many miles through pipelines. At the other end, the coal is used to fuel power plants and other factories.

Oil or Petroleum

Oil is another fossil fuel. It was also formed more than 300 million years ago. Some scientists say that tiny diatoms is the source of oil. Diatoms are sea creatures the size of a pin head. They do one thing just like plants; they can convert sunlight directly into stored energy. In the graphic on the left, as the diatoms died they fell to the sea floor (1). Here they were buried under sediment and other rock (2). The rock squeezed the diatoms and the energy in their bodies could not escape. The carbon eventually turned into oil under great pressure and heat. (3) As the earth changed and moved and folded, pockets where oil and natural gas can be found were formed.

Oil has been used for more than 5,000-6,000 years. The ancient Sumerians, Assyrians and Babylonians used crude oil and asphalt ("pitch") collected from large seeps at Tuttul (modern-day Hit) on the Euphrates River. A seep is a place on the ground where the oil leaks up from below ground. The ancient Egyptians, used liquid oil as a medicine for wounds, and oil has been used in lamps to provide light. The Dead Sea, near the modern Country of Israel, used to be called Lake Asphaltites. The word asphalt was derived is from that term because of the lumps of gooey petroleum that were washed up on the lake shores from underwater seeps. In North America, Native Americans used blankets to skim oil off the surface of streams and lakes. They used oil as medicine and to make canoes water-proof. During the Revolutionary War, Native Americans taught George Washington's troops how to treat frostbite with oil.

As our country grew, the demand for oil continued to increase as a fuel for lamps. Petroleum oil began to replace whale oil in lamps because the price for whale oil was very high. During this time, most petroleum oil came from distilling coal into a liquid or by skimming it off of lakes - just as the Native Americans did. Then on August 27, 1859, Edwin L. Drake (the man standing on the right in the black and white picture to the right), struck liquid oil at his well near Titusville, Pennsylvania. He found oil under ground and a way that could pump it to the surface. The well pumped the oil into barrels made out of wood. This method of drilling for oil is still being used today all over the world in areas where oil can be found below the surface. Oil and natural gas are found under ground between folds of rock and in areas of rock that are porous and contain the oils within the rock itself. The folds of rock were formed as the earth shifts and moves. It's similar to how a small, throw carpet will bunch up in places on the floor. To find oil and natural gas, companies drill through the earth to the deposits deep below the surface. The oil and natural gas are then pumped from below the ground by oil rigs (like in the picture). They then usually travel through pipelines or by ship.

Oil is found in 18 of the 58 counties in California. Kern County, the County where Bakersfield is found, is one of the largest oil production places in the country. But we only get one-half of our oil from California wells. The rest comes from Alaska, and an increasing amount comes from other countries. In the entire U.S., more than 50 percent of all the oil we use comes from outside the country...most of it from the Middle East. Oil is brought to California by large tanker ships. The petroleum or crude oil must be changed or refined into other products before it can be used.

Refineries

Oil is stored in large tanks until it is sent to various places to be used. At oil refineries, crude oil is split into various types of products by heating the thick black oil.

Oil made into many different products - fertilizers for farms, the clothes you wear, the toothbrush you use, the plastic bottle that holds your milk, the plastic pen that you write with. They all came from oil. There are thousands of other products that come from oil. Almost all plastic comes originally from oil. Can you think of some other things made from oil? The products include gasoline, diesel fuel, aviation or jet fuel, home heating oil, oil for ships and oil to burn in power plants to make electricity. Here's what a barrel of crude oil can make. In most states, 74 percent of oil is used for transportation -- cars, planes, trucks, buses and motorcycles.

Source: American Petroleum Institute (www.api.org). Figures are based on 1995 average yields for U.S. refineries. One barrel contains 42 gallons of crude oil. The total volume of products made is 44.2 GALLONS - 2.2 gallons greater than the original 42 gallons of crude oil. This is called "processing gain," where other chemicals are added to the refining process to create the products.

Natural Gas

Sometime between 6,000 to 2,000 years BC, the first discoveries of natural gas seeps were made in Iran. Many early writers described the natural petroleum seeps in the Middle East, especially in the Baku region of what is now Azerbaijan. The gas seeps, probably first ignited by lightning, provided the fuel for the "eternal flames" of the fire-worshiping religion of the ancient Persians. Natural gas is lighter than air. Natural gas is mostly made up of a gas called methane. Methane is a simple chemical compound that is made up of carbon and hydrogen atoms. It's chemical formula is CH₄ - one atom of carbon along with four atoms hydrogen. This gas is highly flammable. Natural gas is usually found near petroleum underground. It is pumped from below ground and travels in pipelines to storage areas. Natural gas usually has no odor and you can't see it. Before it is sent to the pipelines and storage tanks, it is mixed with a chemical (mercaptan) that gives a strong odor. The odor smells similar to rotten eggs. This odor makes it easy to smell if there is a gas leak.

Generating Electricity

Think back to the previous chapters and look at this diagram

Nuclear fission reactors produce electricity in much the same way that conventional fossil fuel power plants do. The thermal energy released from the fission process is used to boil water and produce steam. Look at the diagram below and trace the flow of steam:

Renewable Energy Sources

Renewable energy is the term used to describe energy that comes from sources whose supplies are regenerative and virtually inexhaustible. Among these sources are sunshine, wind, water, vegetation, and the heat of the earth. Throughout history, these sources have been successfully harnessed and used to provide energy. Almost 2,500 years ago, the Greeks designed their homes to use winter sunlight for heating. Large, south-facing windows were used to collect solar heat, which was stored in massive walls and floors for gradual release throughout the night. According to Socrates, the ideal home should be cool in summer and warm in winter. But Socrates' ideal was not easy to accomplish 2,500 years ago in ancient Greece. The Greeks had no artificial means of cooling their homes during the scorching summers; nor were their heating systems, mostly portable charcoal-burning braziers, adequate to keep them warm in winter. Modern excavations of many Classical Greek cities show that solar architecture flourished throughout the area. Individual homes were oriented toward the southern horizon, and entire cities were planned to allow their citizens equal access to the winter sun. The wind has also been used as an energy source for centuries. Some of its early uses include propelling ships and pumping water. Today's technological advancements have developed more efficient means of harnessing and using renewable energy sources, and these sources are gaining increasing popularity. They offer us alternatives to nonrenewable energy sources such as oil, coal and natural gas which, when burned can cause acid rain and contribute to the overall warming of the Earth known as the "Greenhouse Effect." Existing renewable energy installations are making significant contributions to the US energy supply, and research activities are demonstrating the far-reaching impact that a greater reliance on renewable energy sources could have on our country's energy security. In addition, on-going and planned research offers still more possibilities.

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