ScienceWise - Nov/Dec 2008

Ray on sunshine

Article Illustration
Ray Prowse
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The red square illustrates the area of Australia we would have to devote to solar power to supply all our energy needs including all domestic, industrial and transport consumption. If coupled with wind power and hydro the solar red square would be half that size!
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Spread these plants over 200 locations nationwide and the dots above show the land used. hard to see isn’t it!
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Not so hard to see! The regions of Australia experiencing higher mean temperatures than they did in 1970. Most scientists believe this kind of climate change is largely due to burning of fossil fuels. (Based on data from Australian Bureau of Meteorology)

A perspective on the clean energy market

In recent years scientists have been devoting an increasing amount of time to the practical aspects of alternative energy. However just as important as the technology are the economic and political factors that will ultimately make or break the green revolution. Ray Prowse from the Centre for Sustainable energy systems has spent the last ten years managing the development of a variety of new alternative energy technologies.

Ray believes that production of clean energy is just half the picture. "It's often said that the cheapest kilowatt hour is the one you don't have to produce." In other words, it's far better to save energy than to generate it by any means, clean or dirty." At the present time the average Australian household consumes 23 kWh every day. Ray believes that with relatively simple measures such as insulation, double glazing and low consumption light bulbs, this could easily be reduced to 5-8 kWh per day. "In the world of clean energy, this is very much the low hanging fruit" he explains. "If we can halve our energy consumption it would be a huge step on the road to cleaning up out act."

Of course no matter how efficient we become, a modern human lifestyle will still require a considerable amount of energy. Fortunately there are a number of new technologies coming onto the market that will enable us to generate this energy without destroying the environment. However, as Ray explains, "Ultimately it comes down to dollars. The more people who adopt clean energy, the more economies of scale come into play and the more viable it becomes."

We can see this sort of thing happening with most products. Something like a LCD computer monitor is a highly complex piece of technology requiring thousands of manufacturing steps. If you commissioned a lab to build you just one from scratch it would cost tens of millions of dollars. But when everyone in the world orders one, economies of scale bring the cost down to just a couple of hundred dollars.

Ray believes that, in time, this would happen for alternative energy too. But the thing is, we don't have time to wait. So what are needed are some incentives to make clean energy economically viable right now. One such system pioneered in Germany and now being proposed in some Australian States, is Gross Feed-in Terrif. The way this works is that if you have a solar panel on your roof and feed energy into the power grid, you get paid at a premium rate for every kWh. For example if you have a 1kW panel on your roof that might realistically generate about 5 kWh per day, you would receive a payment of perhaps 50cents to a dollar per day. If the panel and its electronics cost $10,000, it's going to take about 25 years to pay back.

"This kind of thing helps, but if we could get the price of the panel right down it would really begin to make economic sense." Ray says. "At the moment 55% of the cost of a solar cell is the high purity silicon it's made of. Reduce the silicon consumption and you reduce the cost. One way we're looking at doing that at ANU is with Sliver cell technology."

To make Sliver cells you pattern the top of a silicon wafer with pin stripes of etch barrier. If the crystal orientation of the wafer and the chemistry are right the etch eats vertically down through the wafer along each pin stripe without spreading sideways. The net result is a chemical saw that cuts the wafer into thousands for slivers. The point being that the surface area of the combined slices is now far bigger than that of the original wafer. This means you can get far more cells for a given amount of silicon.

"Now if your 1kWh solar panel costs only $3,000 and it earns you $500 a year it's starting to sound like a great retirement investment."

Even though a large part of Ray's work involves solar power, he acknowledges that this is only part of the solution. "Wind, hydro and many other clean technologies will also be needed to meet our energy demands. The nice thing about wind and solar is that a lot of the time when it's windy it's cloudy and when it's sunny there's not much wind. So wind and solar make great partner technologies."

Perhaps more than most countries, Australia is in a strong position to generate clean energy. We have lots of land, lots of sun and lots of wind. Ray hopes that we also have lots of good sense to know what's best for us in the long run.

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