Photovoltaic systems – a brief guide
Solar photovoltaic (PV) systems, often known as solar panels, directly convert the sun’s light into electricity using solar cells. PV systems only require daylight, rather than direct sunlight to generate electricity so they can work even on a cloudy day.
How does a photovoltaic system work?
In simple terms, when light shines on a solar panel it creates an electric field across layers of silicone in the cell. The stronger the light, the greater the flow of electricity - PV cells produce electricity in the form of direct current (DC). An inverter is needed to covert this electricity to Alternating Current (AC) which can then be used directly in your building or exported to the national grid.
What you need to know
PV systems now come in a range of shapes and colours, from grey 'solar tiles' that look like roof tiles, to panels and transparent cells. Solar panels are not light and the roof must be strong enough to take their weight, especially if the panel is mounted on top of existing tiles.
PV systems can be used on buildings with a roof or wall that faces within 90 degrees of south. The system should not be overshadowed by other buildings or large trees.
While Installing a PV system can lead to lower energy bills and reduce your carbon emissions it does carry some potential risks and issues which you need to consider before installing:
Always use Microgeneration Certification Scheme (MCS) certificated installers. This should cover all stages of the operation - design, installation and maintenance. The quality of installer and equipment is critical. Poorly installed PV systems as well as the obvious risks with electricity, can lead to roof leaks.
PV systems are not in themselves a fire risk however they can cause problems if the building they are installed on catches fire. High direct current levels, in the panels, can pose problems with fire fighting because the modules cannot easily be switched off and can continue to operate even when damaged. This means that it can take longer to make the premises safe for fire fighters causing more fire damage and increasing the extent of the loss.
Fire can melt the roof anchors that secure PV system modules. They can cause damage to the roof as they fall and a burning PV system can release significant amounts of toxic gas.
Roof anchors must be strong enough to withstand a fire and to minimise the risks posed by large arrays of panels these should be subdivided into smaller sections.
Always ensure a DC Isolating switch is installed.
Cables and power lines to the AC side must be protected by over current devices such as circuit breakers.
PV installations must be separate from existing lightning conductors, and also from likely future positions such as main roof ridges where conductors may need to be placed in the event of an upgrade of the lightning protection system. Surge protection may be required where bonding to the lightning protection system is necessary. Specialist lightning protection advice should be sought regarding separation and installation of surge protection.
Consider security and third party risks - particularly for ground sited systems.
If your building is not connected to the national grid, Solar PV systems can provide alternative energy that may be far more flexible as excess electricity can be stored in special batteries. You will need to consider where you can safely and securely store this extra kit.
If you would like a photovoltaic system to be covered as part of your Parishguard or Hallguard insurance policy, please talk to us before you are due to have the product installed. In order to consider a request, you will need to let us have full details about the installation. It is likely that you will need to increase your buildings sum insured so that you are adequately insured.
Photovoltaic should not be confused with Solar Thermal which is indirect energy generation where the modules (panels) collect the heat from the sun, capture it and transfer it, for example for heating water. Solar Thermal does not present the same issues as there is no DC electricity involved.
For more information, please call us our customer services team on 0345 777 3322.