Nonrenewable Energy Resources and Fossil Fuels Fossil Fuels

Nonrenewable Energy Resources and Fossil Fuels

Fossil Fuels Most of the energy we use comes from a group of natural resources called fossil fuels. � The remains of ancient organisms that changed into coal, oil, or natural gas. �

Fossil Fuels � Two problems 1. Supply is limited. 2. Obtaining them and using them cause environmental issues.

Fuel for Different Uses � Five main purposes for using fuels: 1. Cooking 2. Transportation 3. Manufacturing 4. Heating and cooling 5. Generate Electricity

Factors that Influence Fuel’s Value. � � � Energy content Cost Availability Safety Byproducts associated with its’ usage.

Electricity – Power on Demand Advantages � It is more convenient to power machinery with electricity. � Can be transported great distances easily. �

Electricity – Power on Demand � Disadvantages: � Difficult to store � Other energy sources needed to generate it.

How is it Generated? � By an electric generator, that converts mechanical energy into electric energy. � Generators produce electric energy by moving a conductive material within a magnetic field.

Coal – Fired Power Plant 1. 2. 3. 4. Burning fuel releases energy to heat H 2 O Steam directed against turbine blades causing them to move. Turbine is connected to electric generator and starts generating electricity. Steam from turbine cooled and recycled.

Energy Use United States: � Uses more energy person than any other country in the world except Canada and the United Arab Emirates. � World Patterns: � People in developed countries use more than those in developing countries. �

How Energy is used in the U. S

Why we Use More Energy Person then Most Countries. The U. S uses more than 25% of its energy resources to transport goods and people, mainly by trucks and personal vehicles. � The U. S enjoys some of the lowest gasoline taxes in the world. �

Coal Formation in U. S Oil and Natural Gas Formation: How deposits Form • From the decay of plants that lived in swamps millions of years ago. • From the decay of tiny marine organisms that accumulated on the bottom of the ocean millions of years ago.

Coal � Most of the world’s fossil- fuel reserves are made of coal, Asia and the U. S are particularly rich in coal deposits. Two major benefits of coal: • relatively inexpensive. • Needs little refining after it has been mined. �

Coal mining and its Effect on the Environment. Underground mininglittle effect. � Surface coal-mining- at times, removes an entire mountain top to reach deposits. • Waste rock could leach toxic chemicals into nearby streams. �

Coal and Air Pollution � The quality of coal varies. � Bituminous coal produces more heat and less pollution. � When high- sulfur, low grade coal is burned, it releases a lot of pollution and the end result is acid precipitation.

PETROLEUM Oil that is pumped from the ground. Accounts for 45% of the world’s commercial energy use. � Petroleum products include: • Fuels • Chemicals • Plastics

Locating Oil Deposits Oil is found around major geological features; in folds, faults and salt domes. � These features are bound in impermeable rock, preventing oil from escaping. � � Most of the world’s oil reserves are in the Middle East.

Environmental Effects of Using Oil Release pollutants when burned in internal combustion engines. � Pollutants contribute to smog. � Contribute to global warming. �

Environmental Effects of Using Oil Spills. � Measures taken to prevent them, such as, double hulled tankers. � � Everyday contamination of our waterways- leaking oil from vehicles.

Methane Hydrates Looks like ice. � Contains methane- a natural gas. � Natural gas is increasing in demand for use in new electric power plants. � Could be the fossil fuel of the future? �

Natural Gas 20% of the worlds nonrenewable energy comes from natural gas. � Or Methane CH 4 � In the past was burned off during oil drilling. � Now considered a cleaner alternative to fossil fuels. �

Oil and Natural Gas Reserves in the U. S � Much of the oil and natural gas in the United States is located in : • Alaska • Texas • California • Gulf of Mexico

Predicting Oil Production Oil production is still increasing, but it is increasing much slower than in the past. � Oil reserves are oil deposits that can be extracted profitably at current prices using current technology. �

The Future Fossil fuels supply 90% of the energy used in developed countries today. � As demand increases in the future, prices will increase. � Alternative energy will become attractive. �

Nonrenewable energy Nuclear Energy

Nuclear Energy In the 50’s and 60’s nuclear energy was the future. � In the 70’s and 80’s over 120 planned nuclear power plants were canceled , and about 40 partially built plants canceled. Why? � Today 17% of the world’s electricity comes from nuclear power. �

Nuclear energy is the energy inside the nucleus of the atom. � The force required to hold the nucleus together is 1 million times stronger then the energy stored in chemical bonds of molecular compounds. �

Fission: Splitting Atoms � When Uranium- 235 atoms are bombarded with atomic particles called neutrons, they collide with one another. � These collisions cause the nuclei of the uranium 235 to split , in a process called Nuclear Fission.

Chain Reaction � Nuclear fission releases a tremendous amount of energy and more neutrons , which in turn collide with more uranium 235 nuclei.

Fission Reaction � If the reaction is allowed to continue uncontrolled, the end result is a nuclear explosion. (Atomic bomb).

Nuclear Power Plants Nuclear power plants get their power from nuclear energy. � Uranium is used as the fuel � They are designed so that the chain reaction is controlled. �

How Nuclear Energy Works Within the nuclear reactor is surrounded by a thick pressure vessel filled with cooling fluid. � The pressure vessel is designed to contain the fission product in case of an accident. � Outside the reactor has thick concrete walls surrounding the reactor. �

INSIDE THE REACTOR Metal fuel rods that contain solid uranium pellets are bombarded with neutrons. Control rods control the rate of fission, by absorbing neutrons. Energy released from the reaction goes into the heat exchanger.

Inside The Reactor � Steam is directed against a turbine, setting it in motion.

Inside The Reactor � The turbine is set in motion generating electricity from the electric generator that it is connected to.

Cooling Towers � A circuit of pipes takes the steam from the turbines into the cooling towers, and the waste heat is released from the cooling towers as steam.

Advantages of Nuclear Power Very concentrated energy source. � Does not release greenhouse gases. � Release less radioactivity then coal burning plants. �

Disadvantages of Nuclear Energy �Cost � Building and maintaining a nuclear power plant is very expensive. � Cost more than $3, 000 per kilowatt of electrical capacity. Wind power s $1, 000 per kilowatt. � Natural gas power plants only cost $600 per kilowatt to build.

Disadvantages of Nuclear Energy � Storing Nuclear Waste Very difficult to do. � Uranium mining and fuel development produces dangerously radioactive waste. � Storage site must be geologically stable for thousands of years. � Yucca Mountain site. �

Disadvantages cont…. Safety Concerns � Poorly designed plants could spell disaster. � Chernobyl in the Ukraine in 1986 was the worst nuclear reactor accident in the world. �

Nuclear Reactor Accident � The U. S also had a nuclear reactor accident at Three Mile Island in 1976.

The Future of Nuclear Energy Nuclear fusion- is a possible energy source. � It occurs when lightweight atomic nuclei of two forms of hydrogen(Deuterium and Tritium) join to form Helium which releases an enormous amount of energy. �

Nuclear Fusion Powers the stars and our sun. Advantages: � Safer energy source � Less radioactive byproducts. �

Why We Don’t Use it � Difficult to achieve. Atomic nuclei must be heated to 180, 000°F. � Nuclei must be contained in high concentration and properly confined. � Technical problems are very complex that building a fusion plant is many years away. �

Renewable Energy Today

Renewable Energy � � � Energy from sources that are constantly being formed. Wind Solar Water Geothermal

Solar Energy Nearly all renewable energy comes directly or indirectly from the sun. � Directly- shines on a window, and heats the room. � Indirectly – generates electricity in solar cells. �

Passive Solar Heating Simplest form of solar heating. � Uses the sun’s energy to heat something directly. � Uses large windows facing the sun. �

Active Solar Heating Energy from the sun is captured by collectors. � Over 1 million homes use active solar heating to heat water. � About 8% of the energy used in the U. S is used to heat water. � Active solar heating could save a lot of energy. �

Active Solar Heating Collectors mounted on the roof contain liquid that is heated as it flows through them. � The liquid is pumped through a heat exchanger, which heat the water for the building. �

Photovolatic Cells These cells convert the sun’s energy into electricity. � Sunlight falls on semiconductor, releasing electrons. The electrons flow through a circuit to the next conductor and so on to generate electricity. �

� Positives � � � Non polluting No moving parts powered by the sun Becoming more efficient, and less expensive Use has doubled every 4 years since 1985 Produces very little electricity � Requires a large area � Need long periods of sun � Negatives Photovolatic Cells �

Wind Power Fastest growing energy source. � Converts the movement of wind into electricity. � Wind turbines are cost effective and can be up and operational in 3 months. �

Wind Farms Large arrays of wind turbines can supply electricity to thousands of homes. � Farmers can sell the electricity to local utility companies. � One drawback- hard to transport from rural to urban area. �

Bio-mass- Power from Living Things Includes plant material, and manure. � Wood and dung are major sources of fuel in developing countries. � Half the wood cut in the world is used for fuel. � If we cut down more than we grow we lose habitat, deforestation, and severe soil erosion. �

Bacteria decomposes organic waste and produces methane. � Burned to generate heat or electricity. � Bio-gas digesters ferment manure and produce methane gas. � Dung- fired power plants use methane given off by cow manure as fuel. Methane Bio-mass- Power from Living Things �

Alcohol Liquid fuels can also originate from biomass. � Fermenting fruit or agricultural waste produces ethanol and alcohol. � Corn is a major source of ethanol. � Cars and trucks run on ethanol. �

Hydroelectricity Hydroelectric energy is produced from moving water. � Accounts for 20% of the world’s electricity. � Water is held back by a dam in a reservoir. � Water is released to turn a turbine, which generates electricity. �

Inexpensive to operate. � Do not release pollutants. � Power plants last longer. � Used for flood control, drinking water, agriculture, industry and recreation. Changes river flow. � Floods large areas of habitat above the dam. � Below the dam -disrupts ecosystems. � Sediments full of nutrients builds up behind the dam. Advantages � Disadvantages Hydroelectricity �

Geothermal Energy- Power from the Earth In some areas, deposits of water in the Earth’s crust are heated by energy within the Earth. � Power plants pump heated water from rock formations and use the steam to turn turbines to generate electricity. � Water is then returned to be heated and used again. �

Geothermal Heat Pumps Used to supply energy for homes. � Heat pumps use stable underground temperatures to warm and cool homes. � A simple loop system of piping that circulates a fluid underground. �

Renewable Energy Summary � Energy from sources that are constantly being formed. � Wind -Converts the movement of wind into electricity. � Solar- Energy harnessed directly and indirectly from the sun. � Water -energy is produced from moving water. � Geothermal- energy from heat in Earth’s interior.