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Solar power

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Solar power

Factors affecting output

There are six main factors that will affect the output from a solar PV system:

  • Total size of the PV array
    Each kWp requires approximately 8m2 of area. A certain area should ideally be left around the perimeter of the array to minimize wind loading and extra turbulence. We aim to leave a border of approximately 1m.

  • Type of module used. These include:

    Shaded chalet, PenzanceAmorphous

    These modules are not too susceptible to shading and are suited to low light levels. We use Unisolar modules. There are even flexible modules of this type available which can be attached to a metal seamed roof.


    Flat roof solution, St IvesPolycrystalline

    These modules are made from multiple silicon crystals and are extremely good value for money. We use the extremely high quality Kyocera modules made in Japan. We often use these modules on LCBP PHASE 2 installations.

    Davey House, PenwithMonocrystalline

    These modules are made from pure silicon crystals and have a higher efficiency than Polycrystalline cells. We often use Sharp modules - these have the added advantage of being manufactured in the UK in Wrexham.

    Penzance YMCAHybrid
    Hybrid modules combine monocrystalline technology along with amorphous. These are top of the range and have an efficiency of 20%! However they are also the most expensive option. We often use either Sunpowered modules or Sanyo modules.


  • The orientation from due south
    The array should ideally face due south. Any deviation from due south will reduce the potential yearly output.

  • The latitude of the installation
    The further south, the better. Click on the map below to see the solar electricity potential for different areas of the UK. As you've probably guessed, Devon and Cornwall are some of the best places in the UK to install solar panels!

    Map of solar output for different latitudes of the UK

  • The angle from horizontal
    The ideal angle from horizontal is between 30-45 degrees. Other angles are also suitable but slightly less efficient.

  • Anything which shades the panels
    Shading of a module can dramatically reduce the output from the whole array. Shading should therefore always be avoided, especially from any trees or buildings to the south of the array.

For full details of the factors affecting output, download our information sheet.