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Energy Explainers: How Does Solar Power Work?

Blog : 13 January 2017

Our upcoming energy report will identify the options for increasing renewable energy generation within the Exeter region. In this series of Energy Explainer blogs we will be breaking down the key technologies that can capture renewable energy, and how they can help us to achieve the goal of energy independence.

There are many forms of renewable energy, and many different technologies for capturing it. The most common is solar panels which capture energy from the sun, and are often seen on top of houses or in fields. But how do the sun’s rays, which we feel as heat on our skin, get turned into electricity?

 

Exeter solar panels

 

In this blog we’re going to look at how solar power works, so take a seat or a sun lounger and let us make you a silicon sandwich.

 

A Silicon Sandwich

Solar panels are made up of photovoltaic cells, and a photovoltaic cell is made up of two layers of silicon. Many electronics use components made from silicon, such as microchips in a computer. It is used in solar panels because it’s a kind of material known as a semiconductor which generates electricity when light hits it.

In order for silicon to generate useful electricity from the sun each layer is treated with a different chemical – one that gives the top layer a negative charge, and another which gives the bottom layer a positive charge.

When the sun hits the negative top layer its energy causes millions of electrons to be released. Electrons are super small particles of matter that carry a negative charge, and are attracted to the positive layer. Their movement produces a flow of electricity.

 

Solar power diagram how does solar work

 

The layers of each cell are sandwiched between metal contacts. If you look closely at a solar panel you can see these contacts. On the front there are very thin metal strips running horizontally, crossed vertically by two or three thicker metal strips.

Multiple cells are fixed together and covered with an anti-reflection coating and glass to produce a panel. The metal contacts of each cell are connected and transfer the electricity generated to wires and into our buildings.

 

Back to the Future

Many people think that solar panels are new technology, but just like electric cars they’ve been around a long time – the first solar cell was invented in 1833, about the same time as the first electric vehicles were developed.

Previously solar panels have been placed on top of roof tiles, making it very noticeable when they’ve been installed. One problem with solar panels has been that some people think they spoil the way things look. Now Tesla has launched its own solar panels to solve this problem. Tesla’s solar roof panels look just like regular roof tiles, meaning solar power can be installed on any house or building without affecting its appearance.

 

Tesla Tiles solar power

 

Solar tiles are perfect for making older and historic buildings energy efficient, as it’s often important to preserve the way they look. An example of a building that will benefit from this new technology is St Margaret’s, a Grade II listed building and sustainable development in Exeter.

 

Where is the Exeter Region’s Solar Potential?

Everywhere! Any area that is lit by sunlight can benefit from solar panels and generate electricity, and solar panels even work when it’s cloudy. Solar installations pointing South, South East, and South West, will generate the most power. Their angle is important too, so some locations will be able to capture more energy than others.

It’s possible to share excess solar energy, meaning none goes to waste and the buildings that generate more power can make up for the buildings that generate less.

Houses connected to the national grid can potentially share their surplus electricity by feeding it back into the grid, although in practice this can be frustrating – if the grid is full the additional solar energy has to be used or lost! In Australia it’s also becoming possible for people to sell surplus energy to their neighbours, but the process for doing this is still in it’s early stages.

Special batteries can store excess power during peak times, with new technologies like Tesla’s Powerwall offering enough capacity to power a two-bedroom house for a whole day.

With more sun hours than many other parts of the UK the South West is perfect for harnessing the power of solar.

 

You can find out more about the Exeter region’s solar power potential in the upcoming energy report which will be available through our Insights page. It will provide a detailed analysis of how solar power can be generated in the region, in addition to other forms of renewable energy, and offer key recommendations for becoming energy independent.