Solar energy


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grp 4 ppt on solar energy

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Solar energy

  1. 1.  yellow dwarf star in the center of the solar system diameter = 1,392,000 km, 109 times of earth’s mass = 2×1030kg, 330,000 times of earth’s 99.86% of the solar system’s total mass ¾ hydrogen, the rest is mostly helium primary source of energy in the earth
  2. 2.  the earth receives 174 petawatts [1015 watts] from the sun 30% is reflected into space and the rest is absorbed by land, oceans, clouds etc. the total energy absorbed by earth’s atmosphere, oceans, land mass is 3,850,000 exajoules [1018 joules] per year energy entering the earth from the sun is twice the energy harnessed from all non- renewable sources of energy combined
  3. 3.  generating electrical power by converting solar radiation into dc electricity using semiconductors that exhibit the photovoltaic effect The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light first observed by Alexandre-Edmond Becquerel in 1839
  4. 4.  also called solar cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect made of monocrystalline silicon or polycrystalline silicon or amorphous silicon or cadmium telluride, or copper indium selenide/sulfide first built by Charles Fritts in1883 by coating the semiconductor selenium with an extremely thin layer of gold
  5. 5.  photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon electrons are knocked loose from their atoms, and current starts flowing through the material and this electricity is captured an array of solar cells converts solar energy into a usable amount of direct current [DC] electricity
  6. 6. “nellis solar power plant” contains 70,000 solarpanels that will generate 25 million kilowatt-hours
  7. 7.  “solar one”, california 1,800 sun-tracking mirrors reflect heat to a central collector
  8. 8.  a solar farm in the philippines…
  9. 9.  pisay
  10. 10.  solar energy is a renewable source of energy in the presence of solar power, use of non- renewable sources of energy like petroleum can be lessened which also lessens pollution unlike others, solar energy can be harnessed and used in remote locations like mountains even though solar panels are expensive, the total amount that would be saved makes the price of the panels will seem small
  11. 11.  solar panels are expensive solar power is inefficient in cloudy areas batteries and solar panels occupy more space solar power maintenance is a problem especially to those who doesn’t know the proper technician disposal is difficult for the batteries and solar panels when they have broken down because they contain toxic chemicals like
  12. 12.  [wikipedia] [google images] the world of science, vol 10, technology of change