what are photovoltaics (PV)?

photovoltaics convert light into electricity, without getting too technical the process utilises semi-conducting materials like silicon. when exposed to light, these semi-conductors release electrons, creating an electric field across 2 or more layers of semi-conductor thereby creating an electric current.

there are different types of photovoltaic cell, which range in efficiency - of course this is a technology in continuous development and as such, more efficient cells will be launched – these are currently the most common:

• the most efficient at around 15% are monocrystalline cells. these are very fine slices cut from a single silicon crystal.

• polycrystalline cells have an efficiency of around 13% and are fine slices cut from a block of silicone crystals. 

• least efficient at around 7% and the amprphus cells – these are constructed of a fine layer of silicon atoms which are then bonded to a glass or metal base. they tend to be used for smaller scale application (calculators for example).

modern PV cells do not require direct sunlight and will work in normal daylight conditions. however, because photovoltaic cells have poor conversion efficiencies at the moment it will generally require a panel array of around 10m2 to make up approximately 30% of the average household electricity requirements over the course of a year. in terms of commercial projects, we generally look at the annual demand and aim to meet a solar fraction of this demand.

panels can be roof mounted or integrated into the structure of the roof, and it is even possible to use PV cells which look like slates, this is important since if is generally a large amount of roof space which needs to be utilised.

if you have any questions about this technology or would like us to carry out a comprehensive analysis of your requirements, please contact us. 

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