The Photovoltaic process is when radiation from the sun is converted directly into electricity.

Semi-conductor materials such as Silicon are used to convert radiation into electricity.

PV panels work even when the sky is overcast, at this time the system will operate by way of indirect sunlight or diffuse light.

PV systems can provide electricity for any household utility and can also be used to sell surplus power produced, back to your power provider.

PV panels provide clean renewable energy.

PV panels produce energy where it is used so energy is not lost during transportation.

PV panels have no working parts and are extremely durable, they will be guaranteed to last over 20 years and should last more than 40. Because they have no working parts the panels require no maintenance.

In just two years the panels will have produced as much energy as it will have taken to manufacture them and after that they are completely beneficial, lowering carbon emissions and saving energy.

PV panels are unobtrusive and take up little space. They only require planning permission in the case of listed buildings and within conservation areas.

PV panels will protect you against rising fuel prices and future fuel shortages.

According to the EST, a PV system will increase the value of your property.

PV systems will give you independence from the grid.

Using renewable forms of energy will make the world a safer less polluted place for your children.

Mono crystalline
Converts 15% of solar energy in to electrical power. Each module is formed from a single silicon crystal which has been sawn into wafers. The process used to make mono crystalline panels is energy and materially intensive and therefore these panels are expensive. Typically they produce the most efficient commercial cells.

Multi crystalline
As multi implies the wafers are not drawn from a single crystal but from a cast block of silicon, which results in aesthetically pleasing random formation of crystals.
Because of the random direction of the crystals the efficiency of conversion of solar radiation is lower, between 8-12%. Sheets of silicon can be drawn rather than sawn making production cheaper than mono crystalline.

Amorphous silicon-(thin film)
It has no long range crystal structure and therefore is quite inefficient.
It can be produced as thin as 1/1000mm.
It is easy to mass produce at low temperatures and with low material input and therefore is cheap to produce.
Because the layers are so thin it is possible to use this type of material on curved surfaces.

Cadmium telluride and copper indium diselenide
This is another form of ‘thin film’ technology which uses a different semi conductor material to silicon.

Building Integrated PV (BIPV)
BIPV integrates the above PV materials into building materials.
For instance: PV roof tiles, PV windows, PV shadings, PV ventilator covers

The smallest functioning PV component is called a cell.

Cells are connected together to form modules or panels.

The panels are attached to the roof by roof mounts or frames.

A collection of modules attached together is called a string of modules, strings of modules attached together form an array.

To convert the power from DC to AC power for the mains and to feed into household appliances, the array is wired through an inverter or several inverters.

Various other wiring and support structures are needed:-it is very important to be able to monitor the output of the system

Costs of systems can vary considerably depending the property and type of installation, but typically for a non integrated 1Kw roof mounted system, using mono-crystalline silicon you will be looking at between £3500-5500 (inc. of tax and subsidy).

It should be noted that the larger the array the cheaper the installation will become per Kw.

Amorphous silicon is cheaper than crystalline silicon but less durable and it requires a large surface area.

Multi crystalline is cheaper that mono crystalline but less efficient.

BIPV systems tend to be more expensive per m2 than modules, but this cost can be offset against the cost of building materials being replaced. An is often perceived and more aesthetically appealing.