PV Solar Panel Information

How do photovoltaic (PV) cells work?

PV cells are panels you can attach to your roof or walls. Each cell is made from one or two layers of semiconducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced.

PV cells come in a variety of shapes and colours, from grey "solar tiles" that look like roof tiles to panels and transparent cells that you can use on conservatories and glass.

The strength of a PV cell is measured in kilowatt peak (kWp). That's the amount of energy the cell generates in full sunlight.

The benefits of solar electricity

• Cut your carbon footprint: solar electricity is green, renewables energy and doesn't release any harmful carbon dioxide (CO₂) or other pollutants. A typical home PV system could save around 1200 kg of CO₂ per year - that's around 30 tonnes over its lifetime.

• Cut your electricity bills: sunlight is free, so once you've paid for the initial installation your electricity costs will be greatly reduced. A typical home PV system can produce around 40% of the electricity a household uses in a year.

• Sell electricity back to the Grid: if your system is producing more electricity than you need, or when you can't use it, someone else can use it - and you could make a bit of money. Read more about feed-in tariffs and selling electricity.

• Store electricity for a cloudy day: if your home isn't connected to the national grid you can store excess electricity in batteries to use when you need it.

Is solar electricity suitable for my home?

Solar panels generate electricity when the sun shines and when it doesn't

To tell if solar electricity is right for you, there are a few key questions to consider:

• Do you have a sunny place to put it? You'll need a roof or wall that faces within 90 degrees of south, and isn't overshadowed by trees or buildings. If the surface is in shadow for parts of the day, your system will generate less energy.

• Is your roof strong enough? Solar panels are not light and the roof must be strong enough to take their weight, especially if the panel is placed on top of existing tiles. If in doubt, ask a construction expert or an installer.

• Do you need planning permission? In England and Scotland, you don't need planning permission for most home solar electricity systems, as long as they're below a certain size, if your home is a listed building, or is in a conservation area or World Heritage Site.

In Wales and Northern Ireland, you still need to get planning permission before installing a solar electricity system - though the legislation may soon change. To find out how to apply for permission, contact you local authority.

Cost, savings and maintenance

Costs for installing a solar electricity system vary a lot - an average system costs between £8,000 and £14,000, depending on its size and type.

In general:

• the more electricity the system can generate, the more it costs but the more it could save
• solar tiles cost more than conventional panels
• panels built into a roof are more expensive than those that sit on top but,
• if you need major roof repairs, PV tiles can offset the cost of roof tiles

Savings can be considerable - almost 1 tonne of CO₂ a year, and around £200 off your electricity bill*. A 2 kWp system could provide around 40% of a household's yearly electricity needs.

Maintenance is generally small - you'll need to keep the panels relatively clean and make sure trees don't begin to overshadow them.

Tariff levels, for technologies installed between 15th July 2009 and 31st March 2012 of most significance to householders