renewable and non-renewable resources environmental science
TRANSCRIPT
Renewable and Non-Renewable Resources
Environmental Science
Energy Resources and Fossil Fuels
• A fossil fuel is a nonrenewable energy resource formed from the remains of organisms that lived long ago; examples include oil, coal, and natural gas.
• Most of the energy we use comes from fossil fuels.
• We use fossil fuels to run cars, ships, planes, and factories and to produce electricity.
Chapter 17
Energy Use in the United States
Energy Resources and Fossil Fuels
• Fossil fuels are central to life in modern societies, but there are two main problems with fossil fuels.
• The supply of fossil fuels is limited.
• Obtaining and using them has environmental consequences.
Chapter 17
Fossil Fuels
How Fossil-Fuel Deposits Form
• Fossil fuel deposits are not distributed evenly.
• There is an abundance of oil in Texas and Alaska, but very little in Maine.
• The eastern United States produces more coal than other areas.
• The reason for this difference lies in the geologic history of the areas.
Coal Formation• Coal forms from the remains of plants that lived
in swamps hundreds of millions of years ago.
• As ocean levels rose and fell, swamps were repeatedly covered with sediment.
• Layers of sediment compressed the plant remains, and heat and pressure within the Earth’s crust caused coal to form.
• Much of the coal in the United States formed about 300 to 250 million years ago.
Ranks of CoalRanks of Coal• Lignite: A brownish-black coal of low quality (i.e., low heat
content per unit) with high inherent moisture and volatile matter. Energy content is lower 4000 BTU/lb.
• Subbituminous: Black lignite, is dull black and generally contains 20 to 30 percent moisture Energy content is 8,300 BTU/lb.
• Bituminous: most common coal is dense and black (often with well-defined bands of bright and dull material). Its moisture content usually is less than 20 percent. Energy content about 10,500 Btu / lb.
• Anthracite :A hard, black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter. Energy content of about 14,000 Btu/lb.
www.uvawise.edu/philosophy/Hist%20295/ Powerpoint%5CCoal.ppt
How a Coal Power Plant Works?
Oil and Natural Gas Formation
• Oil and natural gas result from the decay of tiny marine organisms that accumulated on the bottom of the ocean millions of years ago.
• These remains were buried by sediments and then heated until they became complex energy-rich carbon molecules.
• Over time these molecules migrated into the porous rock formations that now contain them.
Nuclear Energy
• In the 1950s and 1960s, nuclear power plants were seen as the power source of the future because the fuel they use is clean and plentiful.
• In the 1970s and 1980s, however, many planned nuclear power plants were cancelled and others under construction were abandoned.
• Today, nuclear power accounts for 17% of the world’s electricity.
Fission: Splitting Atoms
• Nuclear power plants get their power from nuclear energy.
• Nuclear energy is the binding energy of the atomic nucleus energy released by a fission or fusion reaction
• The forces that hold together a nucleus of an atom are more than 1 million times stronger than the chemical bonds between atoms.
• In nuclear power plants, the element uranium is used as the fuel.
Fission: Splitting Atoms
• The nuclei of uranium atoms are bombarded with atomic particles called neutrons. These collisions cause the nuclei to split in a process called nuclear fission.
• Nuclear fission releases a tremendous amount of energy and more neutrons, which in turn collide with more uranium nuclei.
Nuclear Reactors in the U.S.
How a nuclear reactor works
• http://classic.hippocampus.org/course_locator?course=AP%20Environmental%20Science&lesson=65&topic=1&width=800&height=684&topicTitle=Nuclear%20Power&skinPath=http://www.hippocampus.org/hippocampus.skins/default
Why use nuclear power?Please list the pros and cons of nuclear
power on the index card.Pros Cons
Nuclear Disasters
• Chernobyl • April 28, 1986• A failure of the cooling
system caused a complete meltdown of the reactor core
• 56 died from radiation released from accident
• 4,000 est. will die of cancers from radiation
• http://video.pbs.org/video/1862529183
You decide
• Write an argument using the facts as your support as to whether or not you support the building or new nuclear power plants to provide us with clean energy.
Renewable Energy
• Renewable energy is energy from sources that are constantly being formed.
• Types of renewable energy includes:• solar energy• wind energy• the power of moving water• Earth’s heat.
• Remember, all sources of energy, including renewable sources, affect the environment.
Solar Energy—Power from the Sun
• Nearly all renewable energy comes directly or indirectly from the sun.
• Direct solar energy is used every day, like when the sun shines on a window and heats a room.
• Solar energy can also be used indirectly to generate electricity in solar cells.
Passive solar heating
• Passive solar heating is the use of sunlight to heat buildings directly.– Large windows that face the sun can be used to heat
a home• Active solar heating is the gathering of solar
energy by collectors that are used to heat water or heat a building.– A liquid is heated by the sun as it flows through solar
collectors.– The hot liquid is then pumped through heat
exchangers, which heats water for the building.
Photovoltaic Cells
• Photovoltaic cells are solar cells that convert the sun’s energy into electricity.
• Solar cells have no moving parts, and they run on nonpolluting power from the sun.
• However, they produce a very small electrical current. Meeting the electricity needs of a small city would require covering hundreds of acres with solar panels.
Wind Power
• Energy from the sun warms the Earth’s surface unevenly, which causes air masses to flow (wind)
• Wind power, which converts the movement of wind into electric energy, is the fastest growing energy source in the world.
Wind Farms
• Windmills spin a turbine, which is used to capture the energy from the wind.
• Large arrays of wind turbines are called wind farms. Large wind farms supply electricity to thousands of homes.– In windy rural areas, small wind farms with 20 or
fewer turbines are also becoming common.
• Because wind turbines take up little space, some farmers can add wind turbines to their land and still use the land for other purposes.
Biomass—Power from Living Things
• Biomass fuel consists of plant material, manure, or any other organic matter that is used as an energy source.
• Fossil fuels can be thought of as biomass energy sources, although they are nonrenewable.
• Renewable biomass fuels, such as wood and dung, are major sources of energy in developing countries.
Methane
• When bacteria decompose organic wastes, one byproduct is methane gas.
– Methane can be burned to generate heat or electricity.
• In China, more than 6 million households use biogas digesters to ferment manure and produce gas for heating and cooking.
• Some landfills in the United States generate electricity by using the methane from the decomposition of trash.
Alcohol
• Liquid fuels can also be derived from biomass.
• For example, ethanol can be made by fermenting fruit or agricultural waste.
• Cars and trucks can run on ethanol or gasohol, a blend of gasoline and ethanol. Gasohol produces less air pollution than fossil fuels.
• Some states require the use of gasohol in vehicles as a way to reduce air pollution.
Hydroelectricity—Power from Moving Water
• Hydroelectric energy is electrical energy produced by falling water.
• Hydroelectric energy accounts for 20% of the world’s electricity.
• The water in a reservoir is released to turn a turbine in a dam, which generates electricity.
Geothermal Energy—Power from the Earth
• Geothermal energy is the energy produced by heat within the Earth.
• Although geothermal energy is considered a renewable resource, the water that is used must be managed carefully so that it is not depleted.
Geothermal Energy• Geothermal power plants
generate electricity using the following steps• Steam rises through a well• Steam drives turbines, which
generate electricity• Leftover liquid is pumped back into
the hot rock• The leftover liquid, water, is
returned to Earth’s crust because it can be reheated by geothermal energy and used again.