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  1. 1. Renewable Sources Of Energy Dr. Vivek Kumar
  2. 2. Renewable Energy Sources Solar Wind Hydropower Biomass Geothermal
  3. 3. Solar Power
  4. 4. How Much Solar Energy The surface receives about 47% of the total solar energy that reaches the Earth. Only this amount is usable.
  5. 5. Types of Solar Power Active Passive
  6. 6. Active Solar Power Energy from sun is stored in a “thermal mass” When needed, heat from thermal mass is then pumped throughout structure
  7. 7. Active Solar Power  This also refers to electrical generation using solar power  Two ways to do this are photovoltaic cells and huge commercial electric facilities  This shows the diagram for the house seen in the previous slide. The PV panels are on the roof
  8. 8. Large-scale Solar Electric Site
  9. 9. Large-scale Solar Electric Site These facilities use solar power to heat water to form steam. The steam goes to generate electricity just as in fossil fuel or nuclear electric plants. No release of air pollutants No electricity generated at night They do work on cloudy days, though.
  10. 10. Passive Solar Power Works on the principle that hot air rises and cool air sinks (convection) Solar heats air and it moves through convection through the structure or to thermal mass
  11. 11. Passive Solar Power Mass wall or “Trombe Wall Using back wall as “mass” To rest of house
  12. 12. Solar Power Benefits – Abundant – No greenhouse gases, few other pollutants – Simple, minimal repair needed – Cheap over the long term  Detriments – Retrofitting needed if structure is not already designed as passive solar – Has limitations, night, some locations better such as south rather than north facing slopes – Initial capital outlay can be high
  13. 13. Wind Power
  14. 14. Wind Power • Wind power is the conversion of wind of wind energy into a useful form of energy. • Most modern electrical wind power is generated by converting the rotation of turbine blades into electrical currents by means of an electrical generator. • Wind power is also used to propel ships using sails. • Windmills provide mechanical power, and were originally developed for milling grain for food production.
  15. 15. Wind power Can be used for mechanical tasks, e.g. pumping water Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms.
  16. 16. Electrical Power Windmills High speed, low torque machines Will turn themselves off if wind speed exceeds their limits. Used for generation of electricity for direct use or storage in batteries
  17. 17. Effects of windpower No greenhouse gases Few other pollutants Cheap Abundant Simple Some noise pollution Metal blades interfere with TV & radio reception Aesthetic pollution No evidence for bird death, but can kill bats Positive Negative
  18. 18. Where is wind power available? Wind power not highly suited to these areas
  19. 19. Hydro Power
  20. 20. Hydropower Electric Mechanical
  21. 21. How hydropower works
  22. 22. • The power of flowing water has been used for hundreds of years to operate machinery. This power can also be used to generate electricity. • Large scale hydroelectric schemes involve building a dam across the end of a river valley to create a reservoir. • This is done high up in a mountainous area. • Once they are built, hydroelectric schemes provide a cheap and reliable source of electricity. Hydro Power
  23. 23. Negative effects of Hydropower Flooding the land  Displacement of local inhabitants Local climatic changes Tectonic activities (Earthquakes)  Loss of species (aquatic & terrestrial) Loss of normal nutrient flow down river Changes temperature of water, too
  24. 24. Positive Effects of Hydropower Can generate electricity Can do mechanical work, e.g. grind grain No greenhouse gases Initial construction provides jobs
  25. 25. . Biomass Energy
  26. 26. What Is Biomass Energy • Biomass energy is the use of living and recently dead biological material as an energy source. • Ultimately dependent on the capture of solar energy and conversion to a chemical (carbohydrate) fuel. • Theoretically it is a carbon neutral and renewable source of energy.
  27. 27. How It Works • Traditional: forest management, using wood as fuel • Use of biodegradable waste Examples: manure, crop residue, sewage, municipal solid waste • Recent interest in agricultural production of energy crops  Should be high yield and low maintenance  Examples: corn, sugarcane, switchgrass, hemp, willow, palm oil, rapeseed, and many others  Does not have to be a food crop  Recent interest in bioengineered (GM) plants as fuel sources Production of a liquid or gaseous biofuel Biogas due to the breakdown of biomass in the absence of O2
  28. 28. Biomass Energy Advantages • Versatile • Renewable • No net CO2 emissions (ideally) • Emits less SO2 and NOx than fossil fuels
  29. 29. Biomass Energy Disadvantages • Low energy density/yield In some cases (eg, corn-derived bioethanol) may yield no net energy • Land conversion Biodiversity loss Possible decrease in agricultural food productivity • Usual problems associated with intensive agriculture Nutrient pollution Soil depletion Soil erosion Other water pollution problems
  30. 30. Biomass Pros & Cons Burning biomass gets rid of solid waste Creates energy Creates new markets for crops Burning biomass releases CO2 and other gases associated with combustion Creates solid waste from ash May cause more grasslands to be planted to corn
  31. 31. . Geothermal Energy
  32. 32. Geothermal Energy
  33. 33. How It Works – Geothermal power plants • Use earth’s heat to power steam turbines – Geothermal direct use • Use hot springs (etc) as heat source – Geothermal heat pumps
  34. 34. Advantages • Renewable • Easy to exploit in some cases • CO2 production less than with fossil fuels • High net energy yield
  35. 35. Disadvantages Disadvantages Not available everywhere H2S pollution Produces some water pollution (somewhat similar to mining
  36. 36. Conclusions  Major difficulties in attaining target of 10% of electricity generated by renewables by 2010  Main contributors to this target will be :- 1)Offshore and Onshore windfarms/clusters 2)Biomass/wood, straw, etc 3)Photovoltaic  But policies like Climate Change Levy and the Renewables Obligation will help establish renewables.