Key Points

  • Every roof could be a mini power station Generates electricity directly from the sun
  • No Greenhouse gas emissions when in operation
  • No air pollution when in operation
  • Could be as cheap as fossil fuel electricity in 10 years
  • Good for off-grid sites and electrical appliances

How does it work?

Electricity can be generated directly from sunlight using Photovoltaic (PV) systems. The output of a PV system depends on the size and efficiency of the panels. There are a number of different types of PV panels which are suited to different uses. The efficiency and cost of these panels varies.

In the UK PV panels are usually incorporated into the structure of buildings or appliances rather than set out as a central power station. This means that power is generated close to where it is needed and the PV panel can replace roofing or cladding materials.

The energy captured by PV panels can be used directly or stored in batteries. If a PV system is grid connected, electricity can be “imported” from the grid when there is little sunlight and excess electricity “exported” to the grid in bright sunlight . This means that batteries are not needed.

 

How much energy can it generate?

In the UK there are a small number of houses which supply all or most of their own electricity needs from roof mounted solar panels. This is achieved by combining the PV system with energy efficiency measures to reduce electricity demand.

Most new buildings could be designed to incorporate PV into either roofing or cladding materials making them at least partly self sufficient in electricity. Limiting factors are normally the area available for the PV system and the cost of the system.

Why is it important?

Photovoltaic (PV) panels harness energy from the sun to produce electricity. PV panels can produce electricity without releasing carbon dioxide (CO2), which contributes to climate change.

They do not produce air pollution or contaminate the sea or land during operation. Manufacture of PV panels does not cause any major environmental impacts when compared to other industrial processes.

The components typically required in a grid-connected PV system.

What does it look like?

The most typical form of PV is a rectangular black or dark blue panel. There is increasing variation in the appearance of PV units (see overleaf) as PV coatings can now be added to many different materials such as:

  • PV roof slates which mimic Welsh slate
  • PV shingles
  • PV cladding materials
  • PV incorporated into glazing (providing shading and electricity)

The area required by a system varies, typically a 1kW system can take up between 8-16 square metres.

PV coatings can even be added to some fabrics. Flexible panels are available and PV clothing may be introduced over the next few years.