Solar PV (Photovoltaic)

How it works?

Solar PV panels use the sun to generate electricity. This is DC (direct current) electricity which needs to be converted to AC ( alternating current) by an inverter which is usually placed within the loft of the house.

The AC electricity is then connected to the consumer unit of the house. During the night the house will take electricity from the National Grid and during the day the house will use a combination of the generated "solar PV" electricity and from the National Grid. This operation is done automatically. Electricity Bills are reduced due to offsetting the electricity which is use from the Grid

If the house does not use this Solar PV or "green" electricity then it is fed back to the National Grid automatically. In Europe, these "feed in tariffs" have been introduced for a number of years especially in Germany where the number of Solar PV systems has increased dramatically in the domestic market with subsequent reduction in cost.

What is the typical Energy usage?

The average electricity consumption of a UK household is around 4,700 kWh (kilowatts hours) per year. To understand what a kWh is, a good way is to look at kilowatts hours in a different way, like everyday human activities. A kWh of electricity means:

• 1200 electric shaves
• Drying your hair 15 times
• Listening to 15 CD's
• Using a small refrigerator for 24 hours
• Microwaving 20 meals
• 4 evenings of light with 60W incandescent lamps

In the UK for every kWp of solar PV installed, it generates on average 850 kWh or units of electricity per annum.

There are five main factors that will impact how much energy a solar PV system will generate:

• The total size of the PV array.
• The latitude of the location.
• Which direction the PV panels face; ideal position is a southerly direction.
• What slope the panels are mounted on.
• Anything which shades the panels.

Do I need Planning permission?

Planning permission is not usually required as its falls under "permitted development". However if you live in a conservation area or in a listed building it be worth checking with your local authority.

What is the Installation Process?

The installation of a solar PV system is straight forward with the right supplier/installer who understands the project management process of a solar PV installation.

Feed In Tariffs

The Government announced on 1 February the final details of the proposed new feed-in tariff from April 2010 for microgeneration from systems like small wind turbines and solar photovoltaics. The proposed new tariff will pay for all energy generated by your system, irrespective of if you use it yourself or sell it back to the grid. The amounts paid are in addition to any saving you will make by purchasing less electricity from your supplier and any income you earn from selling your surplus power to your electricity supplier.

The rates that have been announced are significantly higher than previously proposed:

The feed-in tariff will be set at 41.3p/kWh for a typical domestic scale solar PV installation and 26.7p/kWh for both of the small wind turbines that Segen sells. These rates will be index linked to inflation over the life of the scheme.

It was confirmed that there will be no income tax for home owners on revenue from the feed-in tariff, providing the energy generated is used mainly by your own property.

The feed-in tariff will be effective as of the 1st April 2010, but all systems commissioned from July 2009 onwards will qualify for the additional income from the 1st April 2010.