Solar panels

First used to generate power for early spacecraft, solar panels are now found all over the world, powering communities without generating carbon emissions. How do solar panels convert sunlight into electricity? What do you need to keep in mind when designing a solar farm to make it as efficient as possible?

How does a solar panel work?

Solar panels – also known as photovoltaic (PV) panels – are made from silicon, a semiconductor material. Such a material has some electrons which are only weakly bound to their atoms. When light falls on the surface of the silicon, electrons break free and can become part of an electric current.

Illustration of buildings and character with plug and arrows pointing up and down. Image text reads cost, efficiency.

How much power do solar panels provide?

Solar panels have become much cheaper in recent years. They have also become much more efficient – they produce more electrical power from the sunlight falling on them.

Of course, solar panels work best in strong sunlight. They produce most electrical power when the Sun is at its highest – in the middle of a summer’s day – and less early and late in the day and during the winter.

Illustration of graph and building. Image text reads power output, time of day, summer, winter.

Benefits

Solar panels generate electricity without producing carbon dioxide emissions (though there are likely to be carbon emissions during their manufacture).
A PV system has no moving parts to go wrong.
PV panels can last for 20 years or more with very little maintenance so that, once the initial cost has been paid, the electricity they produce is almost free.

Links

Discover more about the physics behind the IOP’s King’s Cross home in a feature from Physics Review (PDF, 1MB). (Originally published November 2019 and reproduced with kind permission of Hodder Education)