Alternative sources of energy


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Alternative sources of energy

  2. 2.  Energy  The ability or capacity to do work  While energy surrounds us in all aspects of life, the ability to harness it and use it for constructive ends as economically as possible is the challenge before mankind  Alternative energy  Refers to energy sources which are not based on burning of fossil fuels or the splitting of atoms.  The renewed interest in this field of study comes from the undesirable effects of pollution both from burning fossil fuels and from nuclear waste byproducts.
  3. 3.  There are many reasons why the world is looking toward alternative energy sources in an effort to reduce pollutants and greenhouse gases.  Alternative, or renewable energy sources show significant promise in helping to reduce the amount of toxins that are byproducts of energy use and help preserve many of the natural resources that we currently use as sources of energy.
  4. 4.  Solar energy is used commonly for heating, cooking, the production of electricity, and even in the desalination of seawater.  Solar power works by trapping the sun’s rays into solar cells where this sunlight is then converted into electricity.
  5. 5.  Additionally, solar power uses sunlight that hits solar thermal panels to convert sunlight to heat water or air.  Other methods include using sunlight that hits parabolic mirrors to heat water or simply opening a room blinds or window shades to allow entering sunlight to passively heat a room.
  6. 6. PROS  Solar power is a renewable resource. As long as the sun exists, its energy will reach Earth.  Solar power generation releases no water or air pollution, because there is no chemical reaction from the combustion of fuels.  Solar energy can be used very efficiently for practical uses such as heating and lighting.
  7. 7. The benefits of solar power are seen frequently to heat pools, spas, and water tanks all over.
  8. 8. CONS  Solar power does not produce energy if the sun is not shining. Nighttime and cloudy days seriously limit the amount of energy produced.  Solar power stations can be very expensive to build.
  9. 9.  Wind energy harnesses the power of the wind to propel the blades of wind turbines.  The rotation of turbine blades is converted into electrical current by means of an electrical generator.  In the older wind mills, wind energy was used to turn mechanical machinery to do physical work, like crushing grain or pumping water.  Wind towers are usually built together on wind farms.
  10. 10.  Now, electrical currents are harnessed by large scale wind farms that are used by national electrical grids as well as small individual turbines used for providing electricity to isolated locations or individual homes.
  11. 11. PROS  Wind power produces no pollution that can contaminate the environment since no chemical processes take place, as in the burning of fossil fuels. There are no harmful byproducts left over.  Since wind generation is a renewable source of energy, we will never run out of it.
  12. 12. CONS  Wind power is intermittent. Consistent wind is needed for continuous power generation. If wind speed decreases, the turbine lingers as less electricity is generated.  Large wind farms can have a negative effect on the scenery.
  13. 13.  Geothermal  Literally means “earth heat”  Geothermal energy  It harnesses the heat energy present underneath the earth.  Hot rocks under the ground heat water to produce steam. When holes are drilled in the region, the steam that shoots up is purified and is used to drive turbines, which power electric generators.
  14. 14. PROS  If done correctly, geothermal energy produces no harmful byproducts.  Once a geothermal plant is built, it is generally self-sufficient energy.  Geothermal power plants are usually small and have little effect on the natural landscape.
  15. 15. CONS  If done incorrectly, geothermal energy can produce pollutants.  Improper drilling into the earth can release hazardous minerals and gases.  Geothermal sites are prone to running out of steam.
  16. 16.  Hydroelectric power  Comes from the potential energy of dammed water driving a water turbine or generator.  Another variation is to make use of water’s kinetic energy or undammed sources such as tidal power.  Hydropower works by harnessing the gravitational descent of a river that is compressed from a long run to a single location with a dam or a flume.
  17. 17.  This creates a location where concentrated pressure and flow of water can be used to turn turbines or water wheels to drive an electric generator.  Electric generators powered by hydro power can be run backwards as a motor to pump water back up for later use.
  18. 18. PROS  Water can be accumulated above the dam and released to coincide with peaks in demand. So, unlike other types of power stations, hydroelectric power stations can promptly increase to full capacity.  Electricity can be generated constantly, because there are no outside forces, unlike other forms of alternative energy, which affect the availability of water.
  19. 19.  Hydroelectric power produces no pollution or waste since there is no chemical reaction to produce power.  Water used for hydro power can be reused.
  20. 20. CONS  Dams can be very expensive to build.  There needs to be a sufficient and powerful enough supply of water in the area to produce energy.
  21. 21.  Tidal energy  Produced through the use of tidal energy generators  Produced by the surge of ocean waters during the rise and fall of tides  Converts the energy of tides into useful forms of power mainly electricity.  These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity.
  22. 22.  Tidal power has great potential for future power and electricity generation because of the massive size of the oceans. However, the amount of water produced so far has been small.  There are currently two commercial-sized tidal power plats operating in the world. One is located in La Rance, France; the other is in Annapolis Royal, Nova Scotia, Canada. There is a third experimental plant operating in Kislaya Giba, Russia.
  23. 23. Tidal Energy generators There are currently three different ways to get tidal energy: tidal streams, barrages and tidal lagoons. For most tidal energy generators, turbines are placed in tidal streams.
  24. 24. A tidal stream is a fast-flowing body of water created by tides. A turbine is a machine that takes energy from a flow of fluid. That fluid can be air (wind or liquid(water). Because water is much more dense than air, tidal energy is more powerful than wind energy.
  25. 25. Unlike win, tides are predictable and stable. Where tidal generators are used, they produce a steady, reliable stream of electricity. Placing turbines in tidal streams is complex because the machines are large and disrupt the tide they are trying to harness.
  26. 26. Barrage  A low dam  Can be constructed across tidal rivers, bays, and estuaries. With a barrage, water can spill over the top or through turbines in the dam because the dam is low.
  27. 27. Turbines inside the barrage harness the power of tides the same way a river dam harnesses the power of a river. The barrage gates are open as the tide rises. At high tide, the barrage gates close, creating a pool, or tide lagoon. The water is then released through the barrage’s turbines, creating energy at a rate that can be controlled by engineers.
  28. 28. Tidal Lagoon  A body of ocean water that is partly enclosed by a natural or manmade barrier  Might also be estuaries and have freshwater emptying into them. A tidal energy generator using tidal lagoons would function much like a barrage. However, these can be constructed along the natural coastline.
  29. 29. A tidal lagoon power plant could also generate continuous power. The turbines work as the lagoon is filling and emptying. Energy output from generators using tidal lagoons is likely to be low. There are no functioning examples yet.