How Do Solar Panels Work?

If you want to generate your own renewable energy at home, then you’re likely to start with solar power. 

But to make the most of this abundant, green energy source, it’s helpful to know the basics of how solar energy systems work. They’re surprisingly simple. 

Capture the Sun

Solar panels convert solar energy from the sun into electricity, even on cloudy days. 

They have no moving parts. Instead, photovoltaic, or PV, cells are grouped together in panels which are usually mounted on your roof. You don’t need planning permission to have them fitted, unless you live in a listed building.

The technology is changing all the time, and panels can now be fitted flush with your roof, or you can eschew panels altogether and opt for solar tiles, although these are more expensive. 

Turn Solar Energy Into Electricity

Each photovoltaic cell fits between two thin layers of semi-conducting materials, usually silicone. When light energy from the sun strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. These electrons can be captured in the form of an electric current.

The power of a PV cell is measured in kilowatts peak (kWp), which is the rate at which it generates energy at peak performance in full direct sunlight during the summer. This might range from 714kWh per annum in the Shetlands to 1132kWh in the South East per kW(p), according to the Solar Trade Association. A kW(p) of solar PV corresponds to around 7m2 of roof space. 

Convert Power Into AC

Solar panels generate a direct current (DC) of electricity. They’re wired into your home and attached to an inverter, which will probably be in your loft, which turns the power into an alternating current (AC), the type of electricity we use day-to-day.

Use, Store or Export the Energy

Your system will automatically use the free electricity you’ve generated, then switch back to using electricity from the grid as needed.

The stronger the sunshine, the more electricity is produced. But if it’s light enough to see, that means solar panels will be able to generate electricity, just at a reduced rate compared with a blazing summer day.

Depending on your location in the UK, a home solar PV system could save around 1.6 tonnes of carbon annually and significantly reduce your energy bills. Plus, with the Smart Export Guarantee, you can earn money by exporting any surplus electricity you don't use.

By adding a home battery to your setup, you can store even more solar energy to use later in the day, maximising the solar energy you generate.

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