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.
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 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.
After decades of improvements, silicon solar panels are nearly as good as they can be. So scientists have been working on new solar technology that doesn’t have the same limitations. Next-generation ‘perovskite’ solar cells can harness 50% more energy from sunlight, and can be made for half the cost of traditional cells.
How does energy from solar panels get to your plug?
The electricity produced by solar panels is called direct current (DC). However, most appliances and power grids use a different type of electricity called alternating current (AC). Each solar installation is connected to a device called an inverter, which changes the DC electricity into AC electricity that can power devices and be used by the grid.
Most solar installations in the UK are connected to the national grid, just like a big power plant, so the electricity can be sent wherever it’s needed. But they can also directly power nearby buildings, reducing their need for mains electricity.
Can solar panels store energy?
Solar panels can be combined with batteries to store the electricity they produce. This is useful if a building needs more energy after dark. For example, you might be out at work all day when the sun is shining, then come home in the evening and want to watch TV or cook dinner. With solar panels and a battery, you could use stored energy generated by your solar panels during the day.
Some systems even let you use an electric car like a household battery that’s charged by your solar panels, and can power other appliances around the house.
Can solar panels be recycled?
Yes, solar panels can be recycled quite easily. The process involves:
Removing the metal frame, glass cover and junction box.
Shredding and processing the cells to separate the silicon and other materials.
Selling the pure materials back into the market, where they can be used to make more solar panels – or any other product.
The problem at the moment is scale. Solar manufacturing has grown much faster than solar recycling. This means there aren’t enough facilities to handle all the worn-out panels coming through the system. The quicker solar recycling can scale up, the more solar panels can be saved from going to landfill.
The world needs more solar power. Here’s how you can help.
Greenpeace has been campaigning for solar power for decades – and it’s working! But to tackle climate change, the world needs to keep plugging in more panels. Join us and let’s make it happen together.
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