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• The Sun is the primary source of energy
• Heat energy radiated by the Sun can be focused over a small area by means of reflectors
• This heat can be used to raise steam and produce electrical energy with a turbine-alternator combination
• Limitations of using solar power:

  • Requires a large area for even a small amount of electric power
  • Cannot be used in cloudy days or at night
  • Considered an uneconomical method
• Solar Power is the energy from the sun that can be converted into thermal or electrical energy
• Solar Energy is the light and radiant heat from the sun that influences Earth climate and weather, and sustains life
• Photovoltaic (PV) is the conversion of light into electricity using semiconducting materials (Silicon) that exhibits the photo-voltaic effect
• Photo-voltaic cells are composed of two different types of semiconductors, a p-type and n-type joined to create a p-n junction
• Light is composed of photons, which can be absorbed by photo-voltaic cells
• Solar panels produce direct current electricity, which can be stored in batteries
• An inverter is required to convert DC electricity into AC electricity
• Wind energy can be used where wind flows for a considerable length of time
• Wind energy is used to run a wind mill which drives a small generator
• Generator is arranged to charge batteries to supply energy when the wind stops
• Advantages of wind power:

  • Negligible maintenance and generation costs
• Drawbacks of wind power:

  • Variable output
  • Unreliable due to uncertainty about wind pressure
  • Power generated is quite small
• Wind Power is the use of air flow through wind turbines to provide mechanical power to generators
• Wind Energy is the energy received from the wind movement across the Earth
• Hydro-power or Water Power is the energy derived from the force of flowing water
• Water energy can be converted into mechanical energy with water turbines
• Water turbines drive the alternator which converts mechanical energy into electrical energy
• Hydro-power is considered a renewable source replenished by rainfall
• Nuclear energy is produced by the fission of uranium and other fissionable materials
• Heat produced by nuclear fission can be utilized to raise steam and produce electrical energy
• Fuel is any substance, natural or artificial, which upon combustion releases heat energy
• Fuels are classified as:

  • Solid Fuels
  • Liquid Fuels
  • Gaseous Fuels
• Fuels are the main sources of energy
• Difficulties in using nuclear energy:

  • High cost of nuclear plant
  • Problems of disposal of radioactive waste
  • Dearth of trained personnel to handle the plant
• Prime movers such as steam engines, steam turbines, internal combustion engines convert the heat energy of fuels into mechanical energy
• The mechanical energy is converted into electrical energy by the alternator
• Reserves of fuels are diminishing day by day (depletion)