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energy. Ms. Hubbuch Chapter 17-18 The Howard School. Fossil Fuels . Remains of ancient organisms that changed into coal, oil or natural gas Central to life in modern societies Two main problems: The supply is limited Using them causes environmental problems. Uses of Fuels. Cooking
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energy Ms. Hubbuch Chapter 17-18 The Howard School
Fossil Fuels • Remains of ancient organisms that changed into coal, oil or natural gas • Central to life in modern societies • Two main problems: • The supply is limited • Using them causes environmental problems
Uses of Fuels • Cooking • Transportation • Manufacturing • Heating and Cooling Buildings • Generating Electricity
Determining fuel suitability • Scientists look at • Energy content • Cost • Availability • Safety • Byproducts of use
Electricity • Energy in fuels is often converted into electrical energy in order to power machines. • An electric generator is a machine that converts mechanical energy, or motion, into electrical energy.
Energy Use • More developed countries use more energy than developing countries. • U.S. uses more energy per person than everyone but Canada and United Arab Emirates. • Why?
Fossil Fuel Formation • Coal forms from the remains of swamp plants from hundreds of millions of years ago.
Fossil Fuel Formation • Oil and Natural gas form from the decay of tiny marine organisms that gathered on the bottom of oceans millions of years ago.
Coal • Most fossil fuels are coal. • There are two advantages to coal • It is relatively inexpensive • It needs little refining after mining
Coal Underground Mining Surface Mining
Petroleum • Oil that is pumped from the ground is called petroleum. • It is found in and around major geological features. • Exploration wells are drilled to determine the size of the oil deposit. • After it is removed, it is sent to a refinery.
Nuclear Energy • Nuclear power plants get their power from nuclear energy, the energy within the nucleus of an atom. • The process of nuclear fission causes nuclei to split.
Advantages of Nuclear Energy • It is very concentrated • It does not produce greenhouse gases. • It releases less radioactivity than coal fire plants • Good for areas with few fossil fuels
Disadvantages of Nuclear Energy • Safely storing the waste is tough, it stays radioactive for thousands of years • The area must be geologically sound. • Safety is key, fission can get out of control quick.
Future of Nuclear Energy • Nuclear fusion occurs when lightweight atomic nuclei combine to form a heavier nucleus and release tremendous amounts of energy. • Fusion has a lot of potential but has yet to be perfected.
Renewable Energy • Energy from sources that are constantly being formed.
Solar Energy • Power from the sun • 2 Types • Passive – using the suns energy to heat something directly • Based on the summer sun being high and the winter sun being lower.
Solar Energy • Active- gathering the suns energy by collectors for use • Often used to heat water by pumping hot liquid through a heat exchanger
Solar Energy • Photovoltaic cells convert the suns energy into electricity
Wind Energy • Uneven sun energy warming the Earth causes air masses to flow • Wind power converts the movement of wind into electrical energy
Biomass Fuel • Plant material, manure and any other organic matter used for energy
Hydroelectricity • Energy produced from moving water • A dam holds back water which is released to turn a turbine
Hydroelectricity Benefits Disadvantages Disrupts river flow Floods one side displacing organisms Dangerous if it fails Sediment doesn’t travel below the dam Decaying plant matter in the reservoir releases greenhouse gases Interrupts fish migration • Inexpensive to operate • Does not release pollutants • Provides flood control and water to communities
Geothermal Energy • Energy from heat in the Earth’s crust • Pumps bring heated water or steam to a turbine that generates electricity • Some homes use stable underground to heat and cool
Alternative Energy • Energy sources that are still in development • Geothermal was once considered alternative and is now readily used. • To become viable, the source must be proven cost effective.
Tidal Power • Tides are the movement of water in the ocean and sea caused by gravitational attraction between the sun, moon and earth • Tides occur twice a day marked by the rising and falling of sea level • This will not become a major energy source in the future because of cost constraints.
Ocean Thermal Energy Conversion • Works in the Tropics where there’s a big difference between surface and deep temperatures • Has not been proven cost effective
Hydrogen • Most abundant element in the universe • When burned produces water vapor • Not efficient as a fuel yet • Fuel cells produce electricity chemically by combining hydrogen fuel with oxygen from the air
Energy Efficiency • The percent of energy put into a system that does useful work • It is based on the First Law of Thermodynamics
Hybrid Cars • Energy Efficient Vehicles • Consists of a small efficient gas engine and an electric motor
Cogeneration • One way to use fuel more efficiently is to produce two useful forms of energy from the same fuel source
