How solar PV actually generates electricity

You have probably heard that solar panels turn sunlight into electricity. But what actually happens between daylight reaching your roof and that electricity powering an appliance?

Here is the journey in five simple steps.

1. Daylight reaches the solar cells

A solar panel is made from many photovoltaic cells, usually containing silicon.

When daylight reaches these cells, it creates an electrical charge. This produces direct current electricity, commonly called DC electricity.

Solar panels do not need hot weather to work. They generate using daylight, although brighter conditions will normally produce more electricity.

2. The panels produce DC electricity

The electricity generated by the panels is not yet in the form normally used by your appliances.

Cables carry it from the solar panels towards an inverter.

The amount generated at any moment will vary with conditions such as daylight, weather and shading. We explain this further in our guide:

3. The inverter converts it into usable electricity

The inverter is one of the most important parts of a solar PV system.

It converts the DC electricity produced by the panels into alternating current electricity, known as AC electricity.

AC is the type of electricity used by your lights, sockets and household appliances.

4. Your home uses the available solar electricity

Once converted, the electricity enters your home’s electrical system.

When your solar panels are generating, your property can use that electricity instead of buying the same amount from the grid.

For example:

If your home is using more electricity than the panels are producing, the grid automatically supplies the difference.

You do not need to switch between solar and grid electricity manually.

5. Surplus electricity has somewhere else to go

If your panels produce more electricity than your home is using, the surplus can:

• Charge a compatible home battery
• Be exported to the electricity grid
• Potentially earn an export payment through an eligible tariff

Exactly what happens will depend on how the system has been designed and configured.

A simple example

Imagine your solar panels are generating electricity while your washing machine is running:

If the washing machine requires more power than the panels are currently producing, the grid supplies the difference.

If the panels are producing more than the washing machine and the rest of the property need, the surplus is stored or exported.

What happens at night?

Solar panels cannot generate electricity without usable daylight.

At night, your property will normally use electricity from the grid or from a battery if one has been installed and has stored energy available.

Do solar panels work on cloudy days?

Yes. Solar panels use daylight rather than heat or uninterrupted sunshine.

They will normally generate less electricity under heavy cloud than they would during bright, clear conditions, but they do not simply stop working.

Seasonal output and realistic UK generation are covered in our separate guide.

Will solar panels work during a power cut?