A solar PV system consists of an array - a number panels - normally mounted on the roof. The panels are made up of photovoltaic cells,
wafer-thin layers of silicon. The interraction of daylight with the cells produces an electric field - the more sunlight, the more electricity is produced.
This direct current electricity then passes through an inverter, which converts it into alternating-current (AC) electricity for you to use.
A solar PV system will automatically feed the power you’ve generated to your appliances, so much of the electricity you consume during the day becomes free. During the night, or if you need more electricity than you have produced, your power supply will automatically switch back to the national grid, without any disruption.
To make the most of this free electricity, it’s a good idea to use appliances like dishwashers and washing machines during the day. Solar PV systems cannot store electricity - if you produce more than you can use during the day, the excess goes back into the the national grid.
A large portion of the energy your solar panels produce will be exported back to the grid.
In standby mode 90% of the electricity you generate could be exported.
It is assumed that you export 50% of what you generate and this is what you are paid for by your energy supplier at around 5 pence per unit regardless of how much energy is actually exported.
Your energy supplier will then sell it back to you at a much higher rate (typically 12 pence per unit) when you require more energy than you are generating.
It makes sense therefore to harness this energy, prevent it from going back to the grid and use it yourself.
Battery storage enables you store your excess generation for you to use later when your consumption is higher than your generation.