Solar Energy

What is Solar Energy?
Without us maybe realising it, the energy from the Sun is being used all the time in our everyday lives and without it, there wouldn’t be a lot happening on Earth! Without the sun there would be no warmth, no light or no growth on earth, which would mean no life. The solar energy from the Sun can be collected in a number of ways to give us very valuable energy for our homes, schools and communities:

1. Passive solar energy is nothing new – if you have ever been in a car on a sunny day you will have noticed how hot it can get, this is an example of passive solar energy. Buildings can be designed to let heat in during the winter months and block out the Sun during hot summer days. We already make a lot of use of passive solar energy but we often take if for granted.

2. Active solar energy uses the energy from the Sun to give us hot water using a solar collector which is fitted onto the roof of a building. The solar collector is made in such a way that it absorbs heat from the Sun and then heats the water which is stored in a special cylinder for you to use when you need it. Solar water heating collectors are made of dark metal plates and are covered with glass which absorbs heat and let’s the Sun’s rays through.

These pictures show a solar water heating panel and the coil that is inside the hot water tank

3. Solar photovoltaic cells (or PV for short!) use the Sun’s light to produce electricity – ‘photo’ means light and ‘voltaic’ means electric current so although it is a tricky word to say, photovoltaic just means electricity from light.

A single PV cell produces a very small amount of electricity so they are grouped together and connected to form rectangular modules. So that you can get even more power, modules are fitted side by side to form arrays which you can see below:

These show some PV panels up close and also what they look like on the roof of a house

Solar PV roof tiles are now available and they simply replace ordinary roof tiles that you would have on your roof at home with tiles that can produce electricity.

The Switched on Schools programme is helping schools right across Northern Ireland to capture the energy from the Sun to produce electricity so lots of schools will have PV arrays fitted on their school roof. To find out more about the schools taking part and to keep an eye on how much electricity they are generating please click here...

To make best use of the Sun’s energy both solar water heating panels and solar photovoltaic cells need to be positioned so that they are south facing…do you know if you have a south facing roof at home? A south facing roof is one which is facing the Sun at midday.

Solar Energy in use

• Although solar panels work best on sunny days when there are no clouds in the sky and the Sun is shining brightly, they still work on cloudy days because the panels are made in such a way that they can use energy from daylight. There are lots of examples of where solar panels are used on a much smaller scale than the large solar panels which go on the roof.
• One example that you may know of is a solar-powered calculator, which uses light to make it work. Have you seen the large road signs which are powered using solar panels to let people know about road works? What other examples can you find?

Why use solar energy?

• It’s free as the Sun gives out lots of light and heat!
• Energy from the Sun is renewable - it keeps going!
• Solar panels do not cause pollution or harm to wildlife
• Solar panels are safe to use and have no moving parts so they are quiet

Possible disadvantages of solar energy:

• Solar panels can’t produce electricity at night
• PV cells are still quite expensive to buy but there are grants available to help bring down the cost.