The sun gives out more energy in a second than people have ever used.

Of course, only a fraction of that power reaches our earth... but if we can harness some of that heat and light... we can make electricity.

One way is solar cells. Their proper name is photovoltaic cells... photo meaning 'light' and voltaic meaning 'electricity'....

NATHAN BAZLEY, REPORTER: This is a solar cell... And imagine this light is the sun... When the sun shines on this cell... small particles called electrons get excited and move back and forth... That creates an electric current... which travels through these wires and turns on our fan!

When the sun is shining... we have plenty of power to power this fan... but as soon as the sun sets..... no power... and no fan.

Solar cells were originally designed to power satellites in space... Solar is great in space because there aren't any clouds to get in the way...

Cells on earth power anything from calculators to cars...

The kids at Mawson Lakes School even use them....

The solar power goes to the canteen our computers, all our electrical... through the whole school"

This computer tells the kids how the solar cells are working and how much power they're making.....

NATHAN BALEY: There's a little gas symbol... what does that mean?

MADDY: That's all the greenhouse gases we've saved and it's nearly 5000kgs

NATHAN BAZLEY: That's a fair bit... And there's a little dollar sign down here... what does that mean?

MADDY: This is how much money we've saved... which is 1500 dollars...

NATHAN BAZLEY: That's a fair bit isn't it?

MADDY: Yes.

One reason there’s not more solar cells around is because they're expensive, a set up for your house can cost around $20,000.

Another problem is they only make electricity during the day.

But solar cells are getting cheaper and more effective, and researchers are working on better ways to store their power

There's another type of solar power plant that's much simpler and cheaper... they’re called solar thermal cells, which capture heat, not light.

NATHAN BAZLEY, REPORTER: It's really easy... all they are is big mirrors... which intensify the sun's heat.. We direct the beam at pipes full of water, which turns to steam and drives the turbines.

But like photovoltaic cells they only work when the sun's shining.

This is the world's largest solar plant in the Californian desert. It uses 400,000 mirrors to concentrate the sun's energy. The same idea is used for the solar water heaters that people put on their roofs.

They heat the water for your shower in the morning... but instead of using mirrors... they use black material to absorb the sun's rays and heat the water.

Some solar power supporters say if a 50 kilometre by 50 kilometres solar thermal unit was built in the centre of Australia it could supply all the country's power in 2020.

That sounds impressive but a lot more development is needed to make it a reality.

But critics believe the money would be better used on other types of energy.

Solar scientists say if they can find solutions. Australia could have a very sunny future.

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Now it's time for a quiz.

What is the sun made of? Is it;

a. gas
b. molten rock
c. highly energised electrons

ANSWER: (a) gas. The gas that makes up most of the sun is hydrogen.