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Renewable sources of energy. Solar Energy. The sun constantly gives off energy in the form of light and heat . Earth receives enough solar energy to meet the energy needs of the entire world for 40 years. Advantages : It does not cause pollution Abundant availability, It will not.
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Solar Energy • The sun constantly gives off energy in the form of light and heat. • Earth receives enough solar energy to meet the energy needs of the entire world for 40 years. • Advantages: • It does not cause pollution • Abundant availability, It will not. Disadvantages: • Its only available when the sun is out and it is very spread out.
Solar Technologies • Solar Plants: Rows of giant mirrors focus the sun’s rays to heat a tank of water. The water boils, making steam that is used to generate electricity. • Solar Cells: consists of a “sandwich” of very thin layers of the element silicon and other materials.
Solar Heating Systems • Passive: converts sunlight into thermal energy without using pumps of fans. • Active: captures the sun’s energy, then uses fans and pumps to distribute the heat.
Wind • Wind energy is an indirect form of solar energy. • The differences in pressure cause winds as air moves from one area to another. • Wind can be used to turn a turbine and generate electricity.
Hydroelectric power • Hydroelectric power is electricity produced by flowing water. • It is the most widely used source of renewable energy in the world today. • Advantages: • It is inexpensive. • No pollutions • Provides a steady supply of energy.
Tidal Energy • Tides are another source of moving water. • The gravity of the moon and sun causes the water on Earth’s surface to rise and fall on its shores. • A few tidal power plants have been built to take advantage of this regular motion.
Biomass Fuels • The oldest fuel used for heat and light is wood. • Other biomass fuels are leaves, food, wastes and manure. • Biomass materials can be converted into other fuels; • Gasohol-corn makes alcohol, add alcohol to gasoline produces fuel for cars. • Bacteria decomposes turns into methane gas is used to heat buildings.
Geothermal energy • Intense heat from Earth’s interior. • Geothermal energy is an unlimited source of cheap energy. • Disadvantages: • Only a few places where magma comes close to Earths surface. (Iceland) • Need to drill deeper wells (expensive)
Hydrogen Power • Energy of the future: • Burns cleanly • Water is its only by-product • It creates no smog, smoke or acid rain. • Can be handled and transported through pipelines. • Exists on Earth in large supply. Disadvantage: Almost all of Hydrogen is combined to Oxygen