Electricity generation in the UK today is still largely sourced from fossil fuels, which causes the release of harmful gases into the atmosphere – including CO2. The use of solar electricity generation will help to reduce the emission of these gases thereby helping government to meet their binding 2020 emission reduction targets.
We use a system called Photovoltaic (or PV for short), which generates electricity by converting daylight into electricity. The solar panels which are normally located on your roof are comprised of solar cells. 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.The strength of a PV cell is measured in kilowatt peak (kWp). That’s the amount of energy the cell generates in full sunlight.These cells produce direct current (DC) which is then converted to alternating current (AC) by an inverter, so the electricity generated by the solar panels can then be used to power appliances in your home or workplace.
Typically domestic PV Systems come in a range of sizes from 1KW to 4KW.
When the electricity which is generated by the silicon solar cells is not being used, it is sold back into the national grid at a premium rate. It is a popular misconception that solar panels only work when the sun is shining, this is not the case. The panels we install work on natural daylight, so in essence they are producing electricity for you from dawn until dusk. At night when you have demand for electricity you simply draw your power from the national grid again, as you do now.
Crystalline silicon technology is the most commonly used in the UK and the most efficient at converting sunlight into electricity. It consists of thin slices of silicon cut from a single crystal (monocrystalline) or from a block of crystals (polycrystalline).
Monocrystalline cells are cut from a single crystal of silicon- they are effectively a slice from a crystal. Monocrystalline performs most efficiently with modules typically converting 15% or more of solar radiation into electrical energy, and with the best products reaching 21.5%. The higher price reflects this. In appearance, it will have a smooth texture and you will be able to see the thickness of the slice. These are the most efficient and the most expensive to produce. They are also rigid and must be mounted in a rigid frame to protect them.
Polycrystalline (or Multicrystalline) cells are effectively a slice cut from a block of silicon, consisting of a large number of crystals. They have a speckled reflective appearance and again you can you see the thickness of the slice. Polycrystalline silicon converts between 8 and 12% of solar radiation into electricity. These cells are slightly less efficient and slightly less expensive than monocrystalline cells and again need to be mounted in a rigid frame.
As a rule of thumb, we use monocrystalline panels for our solar installations. We are normally able to do so very cost effectively and usually our prices are on a par with our competitors who use the less efficient polycrystalline solar panels.
The inverter is an important part a PV system. It ensures that the output voltage from the PV modules is slightly higher than the voltage coming from the grid. This means that appliances will use the electricity from the PV system before drawing from the grid – thus reducing consumption of more expensive electricity. Surplus electricity from the PV system will be automatically exported back to the grid.
Our Government has recognised the potential for Photovoltaic systems for both domestic and commercial buildings and has introduced the Feed-in-Tariffs as an incentive to encourage take-up with the aim of giving an 8 to 12% return of investment.