The term “photovoltaic” is derived from the Greek word “photo” which means light, and the word “volt” which was named after Alessandro Volta, who was responsible for developing the first electric cell in 1800. From these two words, you can see that photovoltaic (PV) panel technology converts light into electricity. Radiation from the sun carries ‘photons’. Photons are discrete packets of energy, and it is these that interact with electrons on a PV panel when sunlight hits them. These electrons then travel around a circuit, forming a ‘direct electrical current’ (or Direct Current, DC). Because the PV panel generates a DC, the supply will have to be converted into an Alternating Current (AC) so that it can be exported to the national grid. The diagram below shows a simple illustration of this.
Suitability
In order to maximise its performance, it is important to have your PV panel situated in the right place. Because the UK is in the northern hemisphere, a panel should be installed at an angle of 30o from the horizontal and pointed south to gain maximum sunlight intensity.
You must have an area, usually on the roof, large enough to house a PV panel. Typically, this is anywhere between 8-15m2 per kWp [kWp - kilowatt peak, is the maximum capacity that a panel can generate under perfect conditions].
The strength of you roof is also something for consideration. A site survey will ascertain whether your roof will be able to hold an installation. If you have a flat roof, then panels can be installed on an angled frame.
Cost & Payback
You should take into consideration the fact that your energy consumption will probably not be met by a PV installation. Firstly, your demand for energy may be too large for the PV panel to generate enough energy for, and secondly, your biggest demand is likely to be during the evening when there is limited or no sunlight available. For these reasons, a PV panel is only likely to generate 30-40% of your energy consumption requirements. Obviously, with more energy efficient appliances and practices, the percentage should be higher.
A 3 or 4 bedroom house would be recommended a PV array (array is a collection of panels) rated around 2kWp. For an installation, the cost is around £5,000+ per kWp. So a 2kWp system would be around £10,000.
What You Expect To Generate
An example cost and saving estimation is given below for two PV panels rated at 2kWp and 2.5kWp. Both assume that the owner uses 75% of the energy the panel generates for their own consumption, and an inflation of 3%.
These panels would be suitable for a 3 or 4 bedroom household.
The Feed-In-Tariff (F-I-T) was brought in to replace the old Low Carbons Building Program which offered a grant. The F-I-T pays you (from the tax payer) a set price per kWh for everything you generate, regardless of whether you use the electricity or not. On top of this, for all the electricity that is not used and which therefore goes to the grid, the energy company you are registered with will pay you 3p per kWh.
What’s the catch? There isn’t one really. The lifespan for the F-I-T and PV panels will run out and therefore stop paying from 2034 (so is finished by 2035). It starts with 41.3p/kWh for 2010 to 2012. After this, the tariff goes down in increments of a few pennies. This means that if you install a PV panel between 2010 and 2011, you will get 41.3p/kWh every year until 2034. If you install a PV panel in 2012 you will get 37.8p/kWh every year until 2034. The decrease in F-I-T is expected to reflect the decrease in installation cost.
How To Go About Getting It Installed
The good news on getting planning permission for a PV installation is that you don’t need any! However, for a free standing PV panel, or an installation on a registered building this will need to be checked out with the local planning authority. Unfortunately, if you live in Wales or Northern Ireland, you will need to get planning permission!
There are many installers of PV panels around the UK but before hiring one you should check that these are accredited with the Mircogeneration Certification Scheme.
Get a quote today with ESW for a solar PV project for your home.
Maintenance
PV panels have very little maintenance. To ensure the efficiency of your panel it will have to be cleaned every now and again so that it can collect as much sunlight as possible. The company that installed the panel should come round to your house every few years to do a service check (and this should be included free in the installation price, although it is best to check this before having the panels installed).
