How do solar PV panels work?
A solar PV system captures the sun’s energy and uses it to generate electricity. The system will continue to work even in cloudy conditions. Not only could you save money by generating your own electricity, you could also earn money from the Government's Feed-In Tariff.
Technical information made simple
Solar PV panels are made up of solar cells. Each cell is made from one or two layers of semi-conducting material, typically silicon, covered by non-reflective glass. Here’s how a typical system works:
- The light shines on the cell and this creates an electric field across the layers, causing electricity to flow.
- The electricity flows through a cable and is collected at a central point generally under the panels and located in your roof space.
- The electricity produced is Direct Current (DC) and needs to be converted to Alternate Current (AC) by an inverter which is fitted as part of the system. This is AC current is then used in your home to power your lights and appliances.
- If you don’t use all the electricity that you have generated, it will be fed into the National Grid automatically. It is estimated that you will export 50-75% of the electricity you generate. If the system can’t provide you with enough electricity, i.e. at night, the Grid will automatically supply you as it does now, for which you will be charged.
The stronger the sunshine, the more electricity you can produce, but PV cells don’t need direct sunlight to work – you can still generate some electricity on a cloudy day.
The strength of a PV cell is measured in kilowatt peak (kWp). That’s the amount of energy the cell generates in full sunlight. This rating will determine the amount of electricity that you can produce. Typical domestic units are 3 or 4 kWp.
- Can I export the electricity I generate using a solar PV system?
- Yes, one of the benefits of the Feed-In Tariff scheme is that you can earn an extra 4.5p per kWh that is generated then exported. All unused electricity will automatically be exported unless you connect batteries to your system. Your electricity company can fit an export meter or they can pay you based on estimated export rates (usually 50%) - sometimes your electricity supplier can authorise installers to fit the export meter instead. Do not confuse the export meter with the gross generation meter, which is fitted as standard on all solar PV installations.
- How does the electricity I generate with solar PV get into my wall sockets?
- Your installer will connect the solar PV system to your fuse board (consumer unit). The electricity will automatically flow from there to wherever it is needed.
- Do I need a three phase electricity supply to install solar PV?
- Systems with up to about 10kW peak power don't need more than a single phase electricity supply, however it is very unlikely that your system will exceed 4 kW peak power. Your installer will advise you exactly what is required.
- Do solar PV installation prices include the price of scaffolding?
- Some PV installers do not include the cost of installing the necessary scaffold at your property when quoting costs. Make sure that you check this when comparing quotes from various installers.
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