Solar power is one of the great success stories in the fight against climate change. The first proper solar panel was invented back in 1881, but in the last 15 years the technology has really taken off. These days they’re a common sight on rooftops and in fields all over the country.
But how do solar panels actually work? In short, solar panels absorb tiny particles of light called photons.
- When the photons hit the panel, they dump their energy into it.
- This energy finds its way to particles in the panel called electrons.
- The added energy ‘excites’ the electrons and allows them to move around.
- They move towards a metal strip called an electrode and this causes an electric current.
- The current then flows out of the solar panel and into whatever it’s connected to.
That’s the basic summary. Read on to learn more about how solar panels work, or keep exploring the amazing world of renewable energy.
The basic building block of a solar panel is the solar cell. A normal solar cell is made from two thin slices of silicon Silicon is the same stuff that's used to make computer chips. It's made from a mixture of glass and sand sandwiched together. The two layers have been chemically treated to give them different electrical properties, and it’s this difference that makes the magic happen. You can read more about this process here.
If you look at a solar cell up close, you’ll see thin white lines running across the surface. These are the electrodes – metal strips that collect the electricity produced in the cell. On the back of the cell there’s a thin sheet of metal that does the same job, but this one can be solid because it doesn’t need to let light through.
If you see a detailed blue crystal pattern on the surface of the cell, you’re looking at a ‘polycrystalline’ cell, which is made by melting multiple silicon crystals together. Monocrystalline cells are plain black, and made from a single silicon crystal. These are more efficient, but more expensive.
A technician inspects new solar panel components in a factory. © Paul Langrock / Zenit / Greenpeace
A standard solar panel that might go on your roof is made up of around 60 solar cells wired together under an anti-reflective glass cover, with a metal frame around the outside. Panels used in larger installations normally use more cells.
Each panel also has a device called a junction box mounted on the back, which serves as a kind of electrical gateway, ensuring that electricity can’t flow back into the panel when it’s not producing power.
Do solar panels still work when it’s cloudy?
Yes. Solar panels work best in bright sunlight, but they can still produce plenty of electricity in cloudy weather. That’s because they’re capturing energy from light, not heat.
Do solar panels work well in hot weather?
Yes – in fact solar power production normally peaks on hot days because it’s so sunny!
It’s true that in really high temperatures, solar panels convert sunlight to electricity slightly less efficiently. But all the extra sunshine hitting the panels on hot days more than makes up for the loss of efficiency.
You can tell that heat isn’t a real problem for solar panels by looking at where they’re used. For example, Australia is much warmer than the UK, but the solar panels you’ll find in Sydney are the same ones we use in Southampton.
