Earth image Natural Resources -
Energy Resources

Dr. Pamela Gore
Georgia Perimeter College

Objectives

  1. Discuss renewable resources.
  2. Discuss nonrenewable resources.
  3. Discuss renewable energy resources, including the sun, wind and water energy.
  4. Discuss nonrenewable energy resources, including coal, oil, and natural gas.
  5. Discuss energy use in Georgia.
  6. Discuss energy conservation.
This section addresses, in whole or in part, the following Georgia GPS standard(s):
  • S6E6a. Explain the role of the Sun as the major source of energy and its relationship to wind and water energy.
  • S6E6b. Identify renewable and nonrenewable resources.
  • S6E5i. Describe methods for conserving natural resources such as water, soil, and air.

This section addresses, in whole or in part, the following Benchmarks for Scientific Literacy:
  • The sun is the main source of energy for people and they use it in various ways. The energy in fossil fuels such as oil and coal comes from the sun indirectly, because the fuels come from plants that grew long ago.
  • Some energy sources cost less than others and some cause less pollution than others.
  • People try to conserve energy in order to slow down the depletion of energy resources and/or to save money.
  • Electrical energy can be produced from a variety of energy sources and can be transformed into almost any other form of energy. Moreover, electricity is used to distribute energy quickly and conveniently to distant locations.
  • Energy from the sun (and the wind and water energy derived from it) is available indefinitely. Because the flow of energy is weak and variable, very large collection systems are needed. Other sources don't renew or renew only slowly.
  • Different parts of the world have different amounts and kinds of energy resources to use and use them for different purposes.

This section addresses, in whole or in part, the following National Science Education Standards:
  • When an area becomes overpopulated, the environment will become degraded due to the increased use of resources.
  • Causes of environmental degradation and resource depletion vary from region to region and from country to country.

Resources

Resources can be divided into two categories:

  1. Renewable
  2. Nonrenewable

Renewable resources can be replenished within a relatively short time (perhaps months, or years, or tens of years).
Renewable resources include:

  1. Fresh water
  2. Fresh air
  3. Plants and plant products (food, natural fibers, lumber, fuel)
  4. Animals and animal products (food, leather)
  5. Wind, moving water and sun for energy

Nonrenewable resources form very slowly on or within the Earth, over time periods of millions of years. They accumulate so slowly, that for all intents and purposes on the human time scale, the Earth can be considered to have only a set quantity of the resource. When present supplies are used, there will be no more.
Nonrenewable resources include:

  1. Fossil fuels (coal, oil, natural gas)
  2. Soil
  3. Metallic minerals (iron, copper, gold, silver, lead, mercury, zinc, uranium)
  4. Nonmetallic minerals (kaolin, salt, lime, sulfur, diamonds, sand)

Certain resources can fall into either or both categories, depending on how they are used. These include:

  1. Metals like aluminum which can be recycled
  2. Groundwater, which can be pumped from the ground faster than it is recharged
  3. Plants and animals, which can become extinct
  4. Some forests (such as those in tropical areas) which can be clearcut, which changes the soil and climate so that new trees cannot grow
  5. Air, water, and soil which can be polluted so that they are no longer useful (such as contamination of a water body with radioactive material, or the contaminationof soil with salt or chemicals so that plants can no longer grow in it)


What are the renewable energy resources?

Many renewable energy sources (like solar energy and wind energy), can’t produce energy all the time. The sun doesn’t shine on cloudy days. The wind doesn’t always blow. Unfortunately,renewable energy sources don’t always make energy when or where we need it.

Solar

Solar energy is used for heating water for domestic use, space heating of buildings, drying agricultural products, and generating electrical energy. The major drawbacks of solar energy are:

  1. Sunlight can not be counted on every day in a given location. Some days it is cloudy.
  2. A large area required for solar collectors to collect the sun's energy at a useful rate.
For more information, visit the Energy Kids Page on Solar Energy.


Wind

Wind is air in motion. Wind is produced by the uneven heating of the Earth’s surface by the sun. The Earth’s surface absorbs the sun’s radiation unevenly because some of it is land and some of it is water. During the day, the air over landmasses heats more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air over water moves in to take its place, creating local winds. At night, the winds are reversed because the air cools more rapidly over land than over water.

The large atmospheric winds that circle the Earth are created because the surface air near the equator is warmed more by the sun than the air over the poles. Wind is called a renewable energy source because wind will continually be produced as long as the sun shines on the Earth. Wind energy is mainly used to generate electricity.

For more information, visit the Energy Kids Page on Wind.


Geothermal

The Earth's interior is hot. In fact, the temperature of the Earth increases with depth. Some areas are hotter than others, however. Hot areas are most likely to be tectonically active areas, such as near volcanoes or some tectonic plate boundaries. The ultimate source of the heat is from radioactive decay of radioactive elements (such as uranium) within the Earth.

Volcanic energy cannot be harnessed, but in someplaces geothermal energy, can be collected. Engineers drill into the crust and allow the heat to escape, either as steam, or as very hot water. Pipes carry the hot water to a plant, where some of the steam is allowed to "flash," or separate from the water. The steam then turns a turbine to generate electricity.

Where are the geothermal resources located in the U.S.?
Click here to see a map.

Where are geothermal resources being used in the U.S., and what are they used for?
Click here to see a map.

Generation of energy from geothermal sources is only possible in a few places under unique geologic conditions. At the end of 2002, there were 43 power plants producing electricity from geothermal energy in the U.S. Most of these are located in California and Nevada; Utah has two geothermal plants and Hawaii has one. One geothermal plant in California, called The Geysers, can produce almost as much electricity as all the other geothermal sites combined.

Geothermal energy has a major environmental benefit because it does not produce air pollution. Geothermal energy has a very minor impact on the soil - the few acres used look like a small light-industry building complex. Since the slightly cooler water is reinjected into the ground, there is only a minor impact, except if there is a natural geyser field close by. For this reason, tapping into the geothermal resources of Yellowstone National Park is prohibited by Law.


Biomass

When you burn wood in your fireplace or in your campfire, you are using biomass to generate heat and light energy. Biomass is the sun's energy stored in chemical form within plant material. In addition to wood, biomass fuels include manure, straw, and plant byproducts and waste from a variety of agricultural processes. In the Carribbean, sugar cane is burned as a fuel. Garbage can also be burned as waste, as can methane generated by decaying garbage in landfills.

For years, wood burning was the principal source of energy in much of Europe. As the population grew, large areas were deforested. The Mediterranean region around Greece and Italy was affected by deforestation, grazing and farming which caused a fertile region to become barren and depopulated. Vast forests disappeared, soil eroded away, and rivers and harbors clogged with silt. The population moved to other forested areas and the ruined land and waterways were abandoned. The adverse effects of deforestation and soil erosion on the environment were noted by Theophrastus more than 2,300 years ago.

Deforestation continues in many parts of the world, particularly in rural areas and in non-industrialized countries.

In addition to wood burning, oils derived from crushing certain seeds or from animal fats (tallow) have been burned through the ages. Oil lamps were made in some societies by threading a wick through the body of an oily bird or fish – the Shetland Islanders off Scotland’s northern coast used the storm petrel (Hydrobates pelagicus); native Americans on Vancouver Island, Canada, used a sub-species of salmon.


Hydropower

Hydropower is the use of running water to turn a mill wheel or to turn a turbine to generate electricity. The mechanical energy of the river is converted to electrical energy. There are two types of hydropower. In a" run-of-the-river" system, the force of the current applies the needed pressure for power generation. In a "storage" system, water is dammed up in reservoirs, and released when the demand for electricity is high.


Source: U.S. Energy Information Administration.

Hydropower may be the ideal fuel for electricity generation because, unlike the nonrenewable fuels used to generate electricity, low cost, there are no waste products, and hydropower does not pollute the water or the air. However, dams are criticized because they the environment by affecting natural habitats. For instance, in the Columbia River (Washington/Oregon), salmon must swim upstream to their spawning grounds to reproduce, but the dams gets in their way. There are several possible solutions to this problem, including the construction of "fish ladders" which help salmon "climb up" the dam to go upstream.


Ocean

In some areas, tidal energy in the oceans is used to generate electricity. Tides are produced by the gravitational pull of the sun and the moon on the water. The Bay of Fundy in Nova Scotia, Canada, has the highest tidal range in the world, with high and low tides differing by 16 meters (52.5 feet) each day. There are two high tides per day. This tidal energy can be harnessed. The flow of the water in and out with the tides can be used to turn turbines and generate electricity. A tidal power generating station way built in Annapolis Royal, NS in 1984. It generates more than 30 million kilowatt hours per year - enough to power 4,000 homes.

There are only three tidal power generating stations in the world. The others are in France and Russia. The U.S. has no tidal plants and only a few sites where tidal energy could be produced economically.

The environmental impacts of tidal power generating stations can be far-reaching. Large dam-like structures called "barrages" must be built across inlets where tides come in and go out. They seriously impact plants and animals living in the estuary. They also increase turbidity (mud) in the water, and affect recreation and navigation (preventing boats from passing, which fishermen might depend on for their livlihoods).

Hydrogen

The Sun's energy comes from hydrogen atoms which under high pressures in the Sun's interior fuse together to form helium atoms, releasing heat and light energy. Hydrogen is a gas, that is always combined with other elements. It is not found as a separate gas by itself on Earth. Hydrogen gas must be must made by separating it from water, biomass, or natural gas.

NASA is the primary user of hydrogen as an energy carrier, in the space program. Hydrogen fuel lifts the space shuttle into orbit. Hydrogen batteries—called fuel cells—power the shuttle’s electrical systems. The only by-product is pure water, which the crew uses as drinking water.

Hydrogen is very expensive to make right now, but new technologies may be developed to do it more economically. Hydrogen fuel cells are efficient, but expensive to build. Perhaps one day, small hydrogenfuel cells could power electric cars, and large fuel cells could provide electricity to remote areas.


What are the nonrenewable energy resources?

The nonrenewable energy resources include :

  1. Coal
  2. Oil (petroleum)
  3. Natural gas
  4. Uranium (nuclear)
Fossil fuels originate from the remains of plants, animals, and microorganisms that lived many millions to hundreds of millions of years ago.

The ultimate source of the energy in fossil fuels is the sun, because the fossils fuels came from once living organisms, which were either photosynthetic (plants, algae, microorganisms), or which consumed plant material. Plants and other photosynthetic organisms use the sun, along with water and carbon dioxide gas to produce organic matter. The carbon from the carbon dioxide gas, and the hydrogen from the water, become part of the organic matter of the plant material. When the plant material is eaten by consumer organisms, carbon and hydrogen become part of their bodies too.

There are environmental concerns with the use of any fuel. Burning fuels produces carbon dioxide, which is the most important greenhouse gas. Many scientists have concluded that increasing levels of carbon dioxide and other greenhouse gases in the Earth’s atmosphere are changeing the global climate.


Coal

Coal is formed from plants which lived millions of years ago. Special conditions are required for plant matter to accumulate to form coal. When exposed to the atmosphere, dead plant materials readily decompose. In order to be preserved to form coal, dead plant material must be protected from the oxygen in the atmosphere. The best place to preserve dead plant material is within stagnant water, such as might be found in a swamp, lake, delta, or bog. Swamp water is anoxic or oxygen-deficient. Various types of bacteria decompose the dead plants, releasing hydrogen and oxygen, and as a result, increasing the amount of carbon.

Partially decomposed plant material forms a layer of peat, a soft, brown material which still retains some of the plant structures. (Think about peat moss, if you are a gardener.)

As the dead plant material accumulates in the swamp, it becomes deeper, burying the older plant material. With shallow burial, the peat is converted to a soft brown coal called lignite. With deeper burial, compaction transforms the lignite into a harder black coal called bituminous coal. Lignite and bituminous coal are sedimentary rocks dominated by the organic remains of plants. With increasing temperatures and pressures accompanying greater depth of burial, the bituminous coal is transformed into a metamorphic rock called anthracite, a hard, black, shiny coal.


Source: U.S. Energy Information Administration.

The United States produces more than 1/5 of the world's coal and has nearly 275 billion short tons of coal we can mine. The United States is the world's 4th largest coal exporter, after China. Approximately 60 million short tons are exported every year to about 40 different countries worldwide. Most trade is with Western Europe, Canada and Brazil.


Source: U.S. Energy Information Administration.

Coal is used to generate more than half of all electricity produced in the United States. Power plants burn coal to make steam. The steam turns turbines which generate electricity. Electric utility companies use over 90% of the coal mined in the United States.

Coal is used as a basic energy source in many industries. In addition, a variety of industries use coal's by-products. Coal is baked in hot furnaces to make coke, which is used to smelt iron ore into iron needed for making steel. Separated ingredients of coal (such as methanol and ethylene) are used in making plastics, tar, synthetic fibers, fertilizers, and medicines.


Hydrocarbons - petroleum (oil) and natural gas

Petroleum (oil) and natural gas are called hydrocarbons. They are dominated by two chemical elements, hydrogen and carbon.

The word "petroleum" means "rock oil" or "oil from the earth." Crude oil is a smelly, yellow-to-black liquid and is usually found in underground in porous rocks (like sandstone) called reservoirs.

oil well
Oil well near Guymon, Oklahoma, U. S. Geological Survey

Natural gas received its name because it occurs naturally – often in association with crude oil deposits – and does not have to be manufactured like coal gas. Natural gas is combustible, and when burned, it gives off a great deal of energy. Natural gas is clean burning and emits lower amounts of potentially harmful byproducts into the air, compared with other fossil fuels.

Natural gas is really a mixture of gases. Natural gas is 70 - 90% methane (CH4). But it can also contain up to 20% other combustible gases such as ethane (C2H6), propane (C3H8), and butane (C4H10). Other non-combustible gases are also typically present, including carbon dioxide (0-8%), nitrogen (0-5%), hydrogen sulfide (0-5%), as well as oxygen and other rare gases (less than 1%).

The natural gas that may be piped to your home to fuel your stove, furnace and water heater is almost pure methane, to which a chemical has been added to give it a distinctive odor. Methane is a molecule made up of one carbon atom and four hydrogen atoms.

Oil and gas are formed from the remains of marine plants, animals and microorganisms that lived in seas millions of years ago. Marine algae is the dominant source of oil and gas formation. The remains of dead organisms sank to the seafloor, and were buried in silt and mud over millions of years. Preservation of the organic matter occurs in areas where there is rapid sedimentation and burial, as well as in anoxic or oxygen-poor waters. Heat and pressure from the burial of these layers helps the organic remains turn into oil and gas. The high pressures and temperatures break down the carbon bonds in the organic matter.

Rocks which can generate hydrocarbons may contain between 1 and 20% organic matter. Hydrocarbon source rocks are typically black shales. The organic material is converted to kerogen, a waxy organic substance. At temperatures of 50 to 150 degrees Celsius, and pressures of 300 to 1500 bars, oil is released from the kerogen. Natural gas is formed at much higher temperatures. The liquid oil migrates upward through the pore spaces in the sediments and rocks. Oil moves upward because the sediments beneath the sea are saturated with water. And oil floats on water. Eventually the oil will migrate upward through the rocks, and be caught in a "trap", or it will reach the surface and evaporate. Most oil is extracted from porous sedimentary rocks like sandstones. Sedimentary deposits 1-2 miles deep generally contain both oil and gas. Deeper deposits, far underground, typically contain only natural gas, in many cases, nearly pure methane.


Source: U.S. Energy Information Administration

In some parts of the world, seepages of petroleum-based tar (bitumen) onto the ground surface were used for heating in early times – a feature of some locations in Iraq. Rudimentary oil wells were drilled in China some 2,300 years ago. The beginning of the modern use of oil is usually dated to 1859, when Colonel Edwin Drake drilled the world’s first modern oil well at Titusville, in western Pennsylvania.

After crude oil is removed from the ground, it is sent to a refinery by pipeline, ship or barge. At a refinery, different parts of the crude oil are separated into useable petroleum products. Crude oil is measured in barrels. A 42-U.S. gallon barrel of crude oil provides slightly more than 44 gallons of petroleum products. One barrel of crude oil, when refined, produces 19.9 gallons of gasoline, as well as other petroleum products, such as propane. Many people across the United States use propane to heat their homes, heat their barbecue grills, and and fuel their cars. Other products made from petroleum include: plastics, ink, crayons, bubble gum, and dishwashing liquids.


Source: U.S. Energy Information Administration

gas prices
Gasoline prices - 2006

More than one-fourth of the crude oil produced in the U.S. is produced offshore in the Gulf of Mexico. The top crude oil-producing states are:

  1. Texas
  2. Alaska
  3. California
  4. Louisiana
  5. Oklahoma and New Mexico (tied for 5th place)


Source: U.S. Energy Information Administration

The amount of crude oil produced in the U.S. has been decreasing each year. However, the use of products made from crude oil has been increasing, making it necessary to import more oil from other countries. About 56 percent of the crude oil and petroleum products used in the U.S. comes from other countries.

The world's top five crude oil-producing countries are:

  1. Saudi Arabia
  2. Russia
  3. United States
  4. Iran
  5. China and Mexico (tied for 5th place)

When hydrocarbons are burned as fuel, they release carbon dioxide, a greenhouse gas that is linked with global warming. Burning hydrocarbons also releases pollutants such as carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons that contribute to air pollution. Because a lot of air pollution comes from cars and trucks, environmental laws have been aimed at changing the make-up of gasoline and diesel fuel so that they produce fewer emissions. These "reformulated fuels" are much cleaner-burning than gasoline and diesel fuel were in 1990. In the next few years, the amount of sulfur contained in gasoline and diesel fuel will be reduced dramatically so that they can be used with new, less-polluting engine technology.


Nuclear energy

Nuclear power is generated from the heat released when uranium atoms split (under go fission). That heat boils water to make the steam that turns the turbine-generator. The part of the plant where the heat is produced is called the reactor core.

Uranium-235 (U-235 or U235), is the fuel used in most types of nuclear reactors today. Although uranium is quite common, U-235 is relatively rare. Most U.S. uranium is mined, in the western U.S. Once uranium is mined the U-235 must be extracted and processed before it can be used as a fuel. In its final usable state, the nuclear fuel will be in the form of a pellet roughly one-inch-long, which can generate approximately the same amount of electricity as one ton of coal.


Source: U.S. Energy Information Administration

Nuclear power accounts for about 20 percent of the total electricity generated in the United States. In 2001, there were 66 nuclear power plants (composed of 104 licensed nuclear reactors) throughout the United States, located mostly on the East Coast and in the Midwest. Because nuclear generated electricity does not emit carbon dioxide into the atmosphere, nuclear power plants in the U.S. prevent about as much greenhouse has emissions as taking 5 billion cars off our streets and highways.

Like all industrial processes, nuclear power generation produces wastes: radioactive waste and hot water. Radioactive wastes are the principal environmental concern for nuclear power. Most nuclear waste is low-level nuclear waste. It is ordinary trash, tools, protective clothing, wiping cloths and disposable items that have been contaminated with small amounts of radioactive dust or particles. These materials are subject to special regulation that govern their storage so they will not come in contact with the outside environment.

On the other hand the irradiated fuel assemblies are highly radioactive and must be stored in specially designed pools resembling large swimming pools (water cools the fuel and acts as a radiation shield) or in specially designed dry storage containers. The older and less radioactive fuel is kept in the dry storage facility. It is sealed in special concrete reinforced containers. The United States Department of Energy's long range plan is for this spent fuel to be stored deep in the earth in a geologic repository, at Yucca Mountain, Nevada. Currently, all spent (used) fuel is stored at the power plant at which it was used.


Other - Carbide

Calcium carbide is a grayish-black crystalline compound, CaC2, obtained by heating pulverized limestone or quicklime with carbon (coal tar). When water is added to the carbide, acetylene gas (C2H2) is generated and bubbles off.
CaC2 + 2H2O --> C2H2 + Ca(OH)2

The production of carbide to produce acetylene gas was discovered in 1892. The acetylene burns, producing light, which was used in household lighting in the U.S. before electricity became readily available in rural areas in the 1950's. Carbide lamps were also used for bicycle and carriage lights before electric lamps and batteries became widely available. Carbide lamps are still used by spelunkers (cavers) and miners, and the acetylene gas is also used in welding. Could be purchased in bag of small chunks. Add a few drops of water, light a match.


How is electricity generated in Georgia?

Of the total energy used in the U.S. in 2000, most came from petroleum (39%), followed by natural gas (24%) and coal (23%).

For a map of Georgia Power electricity-generating plants in Georgia, indicating whether using fossil fuels, hydropower, or nuclear, click here. From Georgia Power..


How can we conserve energy?

Visit this website for energy saving tips.


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Page created by Pamela J.W. Gore
Georgia Perimeter College,
Clarkston, GA

Page created March 23, 2005
Modified February 18, 2009