How Does Solar Power Work?

Date: 16/12/21

Think Hire is one of the UK’s leading generator hire companies for sites, and they help our customers take advantage of the carbon-cutting, money-saving benefits of solar power every day. Products like our hybrid power generators and our solar powered site lighting help to harness the power of the sun to produce clean energy for sites across the UK.

The Earth receives more light energy from the sun in an hour than the whole planet uses in a year. The sun gives us 1kW per square metre, or 173,000 GW across the entire surface of the planet, and solar cells help us to harness this free, clean energy and reduce fossil fuel use. But how exactly do solar cells turn light into electricity? It’s all about the clever chemistry inside each of these amazing pieces of technology. Generator hire for sites can really cut your site carbon emissions.

What are solar cells made of?

Solar cells are made of two thin wafers of a semi-conductor called silicon, the second most abundant element on the planet. You probably know it best as sand! These layers are sandwiched between metal plates, with a non-reflective layer above them so that very little light is lost. The top plate is a grid which allows the light through to the silicon layers below.

Here’s the clever bit…

Silicon atoms have four electrons, and in their natural state, these combine to form four bonds with neighbouring atoms, with no electrons to spare. To make the cell work, the top layer – called the N layer – is changed, or ‘doped’, by adding phosphorous, which has five electrons. When this bonds with silicon atoms, there is an electron to spare. The bottom layer – or P layer – is doped by adding boron, which only has three electrons. When this bonds with silicon, it is one electron short, creating a ‘hole’.

How does this create electricity?

When the two layers are brought together, some of the spare electrons from the top layer move across the P/N junction to fill the holes in the bottom layer. This leaves the top layer positively charged and the bottom layer negatively charged. When energetic photons from the sun hit the silicon in the top layer, they release more electrons and create new holes. The charge, or potential difference, between the layers, attracts these free electrons to the top metal plate, creating an electric current.

Does that mean solar panels wear out?

Once they have flowed around the circuit, the electrons return to the bottom of the silicon and fill the holes that have migrated to the bottom layer. This replenishes the silicon and means that it will never be depleted or wear out. Solar cells can last for decades because there are no moving parts and the electrons constantly return to the cell.

How much power does a solar cell create?

Each cell only creates around 0.5V, which is around a third of the output of an AA battery. However, they can easily be combined into panels, and panels combined into arrays, to produce enough power to run a construction site. Solar power contributed around 4% to our national energy supply in 2021, but capacity is expected to grow by around 21% in the next few years.

Who invented solar cells?

Albert Einstein realised that light could be seen as particles, called photons, as well as waves, and that these particles could free electrons from the atoms of semi-conductors under the right circumstances. The idea won him the Nobel Prize. However, it was a team at Bell Labs in the USA in 1954 that really made solar power possible. They came up with the idea of adding impurities to the silicon, paving the way for the photovoltaic solar cells we have today.

How can I benefit from solar power?

Think Hire have a wide range of flexible generator hire for sites, and can design a system to suit all sizes of operation, from a remote track-side rail repair to a large construction site. Talk to our team today about how generator hire for sites and solar power can help cut your costs and reduce your carbon footprint.

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