What is the meaning of PV?

PV stands for Photovoltaics. Literally translated it says: light-electricity. And that’s just what photovoltaic materials and devices do; they convert light energy to electricity.

How does a solar (Photo Voltaic) PV system work?

Solar panels generate electricity using energy from the sun.

When light shines on the cell it creates an electric field across the layers causing electricity to flow. The more intense the light is, the greater the flow of electricity.

Because the panels produce energy from light and not from solar radiation they still produce energy on cloudy days.

The inverter converts the electricity from the solar panels (DC, or Direct Current) into power that can be used by the plugs inside the house for TV, computer, and other wired products (AC, or Alternating Current).

The electricity produced is either consumed directly by appliances in the building, or if more power than required is generated it is exported to the grid. At night or when the system is not producing enough energy, power is supplied by the grid in the normal way.

Do PV modules need direct sunlight to work?

PV modules produce energy from visible light rather than from solar radiation. Therefore, solar modules still produce on cloudy days.

Nevertheless, more power is produced on a sunny day as opposed to an overcast or cloudy one.

What are the effects of shade?

Shading is critical. Minor shading can result in significant loss of energy because the cell with the lowest illumination determines the operating current of the series string in which it is connected.

What happens if there is a Power cut?

A PV systems should be entirely connected. If there is a power cut the system is automatically switched off as a safety measure to ensure power does not leak onto the grid in order to protect personnel working to restore the power supply. There will be no power to the building during the power cut.

What happens at night?

PV panels do not produce energy at night (when there is no actual light) and so electricity is drawn from the grid in the normal way.


Do I need planning permission for installing a solar system?

PV roof systems fall under permitted development rights and so do not require planning permission. However if your building is listed or in an area of outstanding natural beauty, please consult your local council for advice

Do I need to inform building control for installing a solar system?

Yes, you should inform building control about your intentions of installing a solar system. Your installer should instruct you to contact building control.

Do I need to inform my electricity supplier?

For systems less than 4kW peak power your installer should inform your electricity supplier once the system has been installed. For larger systems, permission needs to be given in advance from the network operator.

Is my roof strong enough for installing a solar system?

Most roofs are strong enough to support a PV installation without any reinforcement, though you have to perform a site survey and make an assessment before you start installing a solar system on your roof.