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How Do We Capture Solar Energy?

Solar panels (photovoltaic cells) or PV's, convert the suns rays into energy which is stored in batteries or put into use.

How good a solar cell is at converting the Sun's rays to electricity mostly depends on the size of the crystals used in the cell. There are three main types of solar panels;

Polycrystalline Solar Cells
1. Poly Crystalline Made up of thousands of tiny crystals .These are quicker to produce and therefore cheaper because it is easier to grow lots of small crystals as oppose to one big one.

Mono-crystalline Solar Cells
2. Mono Crystalline Made of one large crystal (can sometimes have a diameter exceeding 12cm). A large problem which has recently been reduced is reflection from the crystals instead of absorbing the energy, they large crystals were just reflecting it back into the sky.

Amorphous Solar Cells
3.Amorphous Made of condensed silicon which are placed as a film on a sheet of glass or plastic. However, with no crystals this is the most inefficient panel, it is also the cheapest to produce. They are found in garden lights and calculators.

Now, there is even a type of paint being developed that can convert solar energy into electricity. Can you imagine the possibilities of that? Every roof could be painted with it and produce all the solar energy we could ever need. The 'paint' is actually a plastic that uses nanotechnology (science that changes atoms and molecules around). Other uses could be to spray it on a jumper to power a mobile phone or a car to power the battery.

Types of collectors:

Rooftop PV - every home should have one!
ROOFTOP PV's:
Can be put on the roofs of factories, offices or homes or set-up in gardens. Are limited by having to face in the direction of the sun.

Parabolic Trough
PARABOLIC TROUGH:
Because of its shape, it can condence the strength of the rays at 30 to 100 times normal strength. Is made up of a large field of collectors to produce larger amounts of power.

Solar Centre Tower
SOLAR CENTRE TOWER:
This consists of banks of flat reflectors which concentrate and shine the sun's rays at a high collector tower. The reflectors can be angled to follow the path of the sun to make the most of its rays which can be concentrated 1200 times!

Solar Power Tower
SOLAR POWER TOWER:
An area of reflectors surrounds a tower. The panels cause heated air to move beneath them up the tower (hot air rises) where it will turn turbines to produce electricity. A company called EnviroMission is about to build one in Australia near Mildura. It will be 400 metres high.

In less than three days, more energy from the sun hits the earth than the total amount of fossil fuels on Earth could ever provide!

Ted Sargent from the University of Toronto says "The sun that reaches the Earth's surface delivers 10,000 times more energy than we consume," and that if we could cover just 0.1 % of the Earth's surface with solar cells we could be self-sufficient on renewable energy.

Don't believe anyone who tells you that solar power could never replace coal. Advances are being made in solar technology all the time. We need to invest in this energy if our planet is to survive.

What can you do? Sign-up for 'Green Power' with your electricity provider. This means that the amount of electricity that you use must come from an alternative energy source such as wind turbines or solar.

By Alastair Wadlow

Info sourced from:
www.solaronline.com.au/page/technical_notes.html
www.solarexpert.com/pvbasics2.html
news.nationalgeographic.com/news/2005/01/0114_050114_solarplastic.html

Images sourced from:
Solar panels on roof: localecology.org/localecologist
parabolic trough: www.eia.doe.gov/kids/energyfacts
solar power tower:www.enviromission.com.au
solar centre tower: www.global-greenhouse-warming.com