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Renewable energy sources
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Advantages

  • The technology can be used almost anywhere since sunlight is available everywhere.
  • The PV modules can almost always be installed close to the place where are consumed thereby avoiding electricity losses associated with transmission and distribution.
  • The installation size can be easily adjusted according to needs and available space.
  • There is no operational pollution, no gaseous discharge, no waste, no risk of physical accidents and no safety issues.
  • There is very little maintenance or repairs as there are no moving parts.

Disadvantages

  • The roof of the building has to be correctly orientated i.e. south facing
  • The daily and seasonal variation which can be overcome by either on site storage or connection to the electricity grid

PV modules

The sun’s radiant energy is transformed into electrical energy without any moving parts or noise. Each cell generates a very small amount of electricity. To obtain a stronger electrical current and to increase the power output, the cells are connected in series to form large photovoltaic panels or modules.

As the cells are extremely thin and fragile, they are protected by a weatherproof enclosure and sheet of transparent, solid glass. Modules are generally rectangular in shape and a few centimetres thick. They can be integrated into construction materials (tiles, slate or transparent frames).

PV systems
A photovoltaic array is simply a small electrical power plant installed as close as possible to where the electricity is needed. There is no need to store the electricity since any excess can be exported to the grid to be used in other dwellings. Electricity can therefore be sold and bought by signing a contract with a grid supplier. A kWh meter records the amount of electrical current exported to the grid so that this electricity can be invoiced to the utility.

PV systems

The other option is to add a battery pack to the solar cell array so that when the supply exceeds demand this electricity can be stored for reuse when the demand exceeds the supply. Which option is chosen will depend upon the unit rate for importing and exporting electricity offered by the utility.

If a dwelling is not connected to the national grid, then electricity needs to be stored when supply exceeds demand as mentioned above. Batteries are the common form of storage as these can store electricity for long periods of time.

KITH # Activity Age range
3.7   Potential for electricity production at your home   
  Science
 9 – 15 
  Potential for electricity production at your school   
  Science
 9 – 15  


 

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