Solar electric panels are made up from silicon cells. Like transistors, these cells have different layers which are treated or ‘doped’ with different impurities.

When daylight falls on them, the light frees up electrons to flow between the layers, creating an electric current.

The electric current created by solar panels is direct current (DC) – it flows one way. But the electricity we use in our homes is alternating current (AC) – it flows both ways switching 50 times a second.

So the DC current from the panels is fed into an inverter which turns it into AC. The inverter synchronises your solar electricity with the incoming supply from the national grid.

When the panels are creating more electricity than you need – for instance on a sunny day when you are out of the house – the surplus flows out into the national grid for other people to use.

When you get home in the evening – it is dark and your panels are not generating – electricity flows into your home from the grid in the normal way to power your TV, cooker etc.