Wednesday, December 18, 2013

Back to basic: How solar cells make electricity

As recently announced, we will soon be part of the national drive to encourage use of renewable energy  - in particular solar PV - to generate electricity. Starting Jan 1 next year, consumers in Sabah will join their counterparts in Peninsula Malaysia to invest in RE.

Solar energy is of particular interest as under the FiT mechanism, solar photovoltaic is one of the four renewable sources of energy in Malaysia that falls under the special tariff where everyone can take part. The others are biogas, biomass and mini hydro.

The following diagram shows how solar cells produce electricity:

Note: Diagram shows one type of panel, other panel may use different type of material.

Type of solar panel construction

Efficiency of a panel is the ability to convert sunlight to electricity. Here are example of different panels. Ratings are for comparison purposes, not a specific panel's rating.

  • Mono-crystalline panels use silicon produced in a continuous sheet, then cut to fit the panel. Typically the most efficient type, but the high silicon levels make them expensive.
    Efficiency: 18%
  • Poly-crystalline panels use groups of small cells instead of one large sheet. Due to lower silicon levels, they are a little less expensive to produce, but slightly less efficient.
    Efficiency: 16%
  • Thin-film panels use very thin layers of material, such as amorphous silicon. Versatile, heat-tolerant and the least expensive type, their lack of efficiency requires more panels. Not as long lasting.
    Efficiency: 9%

Sources: Solar Energy Industries Association, National Renewable Energy Lab., US Dept. of Energy, Mother Earth News, California Solar Energy Industries Association. Diagram/graphics via US Solar Institute.

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