Solar Electricity
Would you like to generate cheap, green electricity from sunlight? Then installing photovoltaic (PV) cells could be for you.
Photovoltaic cells are used in solar electricity systems to capture the sun's energy.
The cells, which can be attached to your roof and walls, convert the sunlight into electricity, which can be used to run household appliances and lighting.
You may think that there are not enough sunny days to warrant investing in a solar electricity system, but PV cells don't need direct sunlight to work - you can still generate some electricity on a cloudy day.
How do photovoltaic (PV) cells work?
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.
So what are the benefits of harnessing this abundant energy source?
Cut your carbon footprint: solar electricity is green, renewable energy and doesn't release any harmful carbon dioxide (CO2) or other pollutants. A typical home PV system could save around 1 tonne of CO2 per year - that's around 25 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 - and thanks to the Feed-In Tariff scheme, you could make a bit of money.
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?
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, Wales Scotland and Northern Ireland, you don't need planning permission for most home solar electricity systems, as long as they're below a certain size - but you should check with your local planning officer, especially if your home is a listed building, or is in a conservation area or World Heritage Site.
Cost, savings and maintenance:
Costs for installing a solar electricity system vary a lot - an average system (2.2kW) costs around £12,000 (including VAT at 5%).
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 - around 1 tonne of CO2 a year. A 2.2 kWp system can generate around 40% of a household's yearly electricity needs. If the system is eligible to receive the Feed-In Tariff it could generate savings and income of around £900 per year.
Maintenance is generally minimal - you'll need to keep the panels relatively clean and make sure trees don't begin to overshadow them.
Selling your own electricity:
You can make money on excess electricity by selling it back to the Grid through a scheme called Feed-In Tariffs (FITs).
Feed-In Tariffs became available in Great Britain on 1st April 2010 and the scheme guarantees a minimum payment for all electricity generated by the system, as well as a separate payment for the electricity exported to grid. These payments are in addition to the bill savings made by using the electricity generated on-site.
Once you have a microgeneration technology installed you should experience a monthly reduction in your electricity bill and then receive an income from your Feed-In Tariff provider. However, if you have taken out a loan to pay for the installation you will have to make monthly repayments to your loan company.
Feed-In Tariffs are designed so that the average monthly income from your installation will be significantly greater than your monthly loan repayment (with a 25 year loan).
For more information on home energy generation technologies, contact your local Energy Saving Trust Advice Centre free on 0800 512 012, or visit www.energysavingtrust.org.uk.