WIND/HYDRO

Sarah Larsen, reporter
SARAH LARSEN, REPORTER: Wind and water. There seems to be a lot of it around at this time of year, and it can be pretty powerful

Fossil fuels. That's where most of the electricity in Australia comes from - coal, oil and gas. They're cheap and effective, but there's only a certain amount on earth and one day they'll run out. They also create greenhouse gases. So countries around the world are turning to renewable energy sources. One of those is the wind

REPORTER: This is a windfarm. Each of those turbines when it's spinning fast enough can power up to 1000 homes.

Turbines can be as tall as a 20 story building so they're anchored into the ground with big foundations. On top is something called the nacelle, which is connected to the rotors. When the wind blows the rotors they turn a shaft connected to a generator to make the electricity. That's then fed down the tower to be used.  When they're running wind farms don't create any air pollution and because the wind is always going to be around, they're never going to run out of power.

Critics say wind power isn't reliable - when the wind stops so does the power generation. Power companies are trying to fix that. A lot of research is done to make sure wind farms are in just the right spot and the weather is closely monitored so they can predict supply. They're also working on better turbine designs and ways to store power. But at the moment windfarms work alongside other power sources so when the wind stops the lights don't go out. Less than one percent of Australia's power supply comes from the wind but in some countries it's much higher - as much as 20 percent.

One natural resource that's already creating a lot of power in Australia is water... with a little help from gravity, that is.

REPORTER: While still water might not look very powerful, when it falls there's a lot of energy to be harnessed. That's what hydroelectric power stations do.

They capture the energy in falling water by running it past turbines. They spin, generating electricity. Australia's biggest hydro power station is the Snowy River Scheme, which generates 10 per cent of New South Wales' electricity. There are also hydroelectric plants in Tasmania, which generate most of that state's electricity. Supporters of hydro power stations say they're great because they don't create any emissions and water isn't used up so it's renewable.. but they do have their critics. They say a lot of greenhouse gases are created when huge and expensive hydroelectric schemes are built and the dams can damage the environment... drowning valleys and choking rivers. Critics' also say rotting plants at the bottom of dams can create greenhouse gases.

All together, renewable energies make up around 9 per cent of Australia's power supply and almost all of that is hydroelectricity. The government says it's trying to increase the amount of renewable energy that's used but some people say it should be doing much more. One problem is that Australia is using more and more power so even though more renewable energy is made, even more fossil fueled electricity has to be made to keep pace.

 

GEO THERMAL

Sarah Larsen, reporter

While wind and water are currently being used to produce some of our electricity, there's a new possibility being explored.  This time we sent Sarah deep underground to check it out....

The earth itself is a 5 billion year old boiler and it's full of power. The earth's own energy is called geothermal power... geo for rock and thermal for heat.

REPORTER: Now up on top the earth is pretty cool. But if I could dig down far enough things would get hotter.  In fact for every kilometre the earth heats up by about 30 degrees. I'd better get started

The centre of the earth is super hot and it's surrounded by molten rock! So all we need to do is get some of that awesome power up to the surface.

In some places that happens naturally. Here in New Zealand there are pools of water boiling just under the surface.

On the other side of the world, in Iceland, there are hot springs, boiling mud and geyers everywhere - half of the country's electricity comes from geothermal energy.

Out in the Australian desert there are no volcanoes, boiling mud or water shooting up out of the ground... but not too far down there are some hot rocks which could be just as useful.

REPORTER: This is the cooper basin in South Australia, and about four and a half km under the ground there's 1000 square kilometres of hot granite. At about 300 degrees Celsius it's more than hot enough to boil water.

This company  - Geodynamics - is planning to use the hot rocks as a big underground kettle.

They're drilling holes into the rock and making cracks in the hard granite below.

Water is sent down the hole and through the cracks where it heats up. The water turns to steam and pours out of another hole where it spins turbines to create electricity.

The water then cools and is sent back down the hole to make more steam so if it works properly nothing should be wasted.

So far Geodynamics has produced some pretty impressive steam.

GEODYNAMICS WORKER: The pressure is actually high enough to force the water 3.5km into the air.

The company says enough hot rock down there to power the whole of Australia for 100 years.

There are hot rocks under a lot of Australia (they're the red bits). Other companies are trying to set up geothermal power in some of those places.

So why aren't we already using them?

Well for starters they've only just drilled holes and haven't connected them to turbines yet.

Setting that up will cost many millions of dollars.

And there's also the cost of getting all the power from out here to here. Critics say that's just too expensive.

But other companies are trying to make geothermal power closer to towns.

And hot rock supporters say the government paid for power lines from fossil fuel plants when they were built so it should help geothermal companies.

The government says it's already giving a lot of money to geothermal development and it's waiting to see some results.

 

SOLAR POWER

Nathan Bazley, reporter

There's a lot of heat under the ground - but there's even more in the sky - do you know where I'm going with this?  That's right- I'm talking about solar energy from the sun.. here's how it works..

NATHAN BAZLEY, REPORTER: 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 jump up and down ... 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.....

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 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 solar 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.

 

Carbon Trading

Nathan Bazley, reporter

Many alternative energy sources are still in the developmental stage... so what else can be done to reduce greenhouse gases? Well one idea being put forward is Carbon Trading - here's how it works...

NATHAN BAZLEY, REPORTER: Imagine the carbon dioxide polluting our atmosphere is the rubbish in this bin...

Right now I can put out as much rubbish as I like and the council will collect it.

But what would happen if the council said I could only put out one bin worth of rubbish?

NATHAN: Hey! I just noticed that you're putting your bin out only half full, whereas I can't fit all my rubbish in mine!

NEIGHBOUR: Well I make sure that I make as little rubbish as possible.

NATHAN: If I give you twenty bucks, would you let me put my rubbish in your bin?

NEIGHBOUR: Sounds good!

Welcome to the new and exciting world of Carbon Trading: A plan that would see us buying and selling... greenhouse gases!

It's a pretty crazy idea, but it could be the solution to a very tricky problem.

The government would impose a cap on how much carbon dioxide big companies can release into the atmosphere.

If a company releases more than their cap, they have to buy (or trade) 'carbon credits' off another company who has reduced their emissions.

So companies can actually make money by being environmentally responsible!

Trees can also be used as 'Carbon Credits'.  Companies can buy big areas of land to plant trees, the trees absorb extra CO2 and keep their business under their cap.

So what does this all mean?

Well for a start, people are predicting that electricity generated using fossil fuels will be more expensive as companies have to pay for every tonne of CO2 they make.

It will also make it worthwhile for those companies to find ways to cut back on their emissions.

Average households could pay an extra 200 bucks a year on their power bill.

On the other hand renewable fuels will become more competitive in comparison, so we could see a lot more investment in green energy!

Both the Government and Opposition want Carbon Trading; but what hasn't been decided is when the plan will be in place, or how tough the emissions cap will be.

NATHAN BAZLEY, REPORTER: I went on the Internet a few weeks ago to buy tickets to a music festival. I noticed that tickets were 194 dollars each, but if I paid extra, they say my carbon emissions to travel to the festival would be offset.

So in this case, the business will plant two trees for me and they say those trees, over 30 years, will absorb the carbon dioxide that I made travelling to the music festival.

Now the tree planting does have critics. They say it just encourages people to keep polluting and one day we'll run out of places to plant trees.

People are also worried carbon trading will take too long to have an effect on the environment.

But if it happens too quickly, they're worried it could wreck the economy.

It's all about getting the balance right and that'll be worked out in the next few years.

And I hope you enjoyed our look at Global Warming - see you next time...