Solar cells price cut in half, cheaper than the grid

	June 18, 2008
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While solar power is clean and green, the great drawback for it has always been cost: it is more expensive than coal or gas-generated electricity. But could that finally be about to change? Researchers at ANU certainly think so. They’ve invented a new kind of solar cell that will slash the cost of solar panels. People will chose to put solar on their rooves, they say, because the panels will provide cheaper electricity than power from the grid.

The new kind of solar cells are called sliver cells, and the reason they are so cheap to manufacture is because they use 90% less silicon than standard solar panels. One of Australia’s largest utility companies is so convinced of the technology’s potential they have bought the rights to it and have already built a pilot factory to produce the new solar panels.

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Transcript

Dr Graham Phillips: We all know that solar is clean and green and could solve so many of our energy problems. But there’s always been that one little snag: it’s more expensive to produce power that way than from fossil fuels. But is that all about to change thanks to an Australian innovation? Well the scientists here at ANU certainly think so and they’ve got industrial backers considering spending 100 million dollars developing their technology. It’s a new kind of solar cell.

Dr Vernie Everett: Yes it is. And we’re that close we can smell it.

Professor Andrew Blakers: We can clearly see a path to producing solar electricity for less than the cost of daytime retail electricityit’s going to be cheaper for a householder to install solar panels on their roof rather than buying more electricity from the grid.

Dr Vernie Everett: The world’s our oyster.

Narration: These are what the scientists are excited about – sliver solar cells. Each of these slivers is a complete solar cell – the smallest commercial cells in the world.

To see why they’ll make solar power cheaper, look at today’s solar panels. Each of those squares is a single solar cell, made from a whole wafer of 99.99999% pure silicon.

These are the pure wafers – and they’re expensive – about half the total cost of a complete solar panel.

But there’s actually a lot of wasted silicon in here, solar cells don’t need wafers this thick. The ANU researchers came up with a clever way of spreading the silicon further, and so dramatically reducing the cost of solar panels.

Slicing silicon wafers like this and turning them into individual solar cells was a challenging task. It involves many steps, laying down thin deposits of chemicals and selectively etching them away.

Dr Vernie Everett: I think in retrospect, if I had have known how much effort and time was involved I think I may not have been so enthusiastic.

Narration: Here are the wafers at various stages of the process. To cut them into slivers required inventing a special etching process.

Professor Andrew Blakers: This allows us to etch all the way through the silicon wafer selectively, only in those areas where we want the etching to take place in.

Narration: Chemically etching all the way through, along lines put on by a laser, was a brilliant way of making 1000s of extremely fine cuts, creating 1000s of sliver solar cells.

Dr Graham Phillips: So that’s the end of the process. So look at the slivers in that!

Professor Andrew Blakers: Yes you can see straight through the wafer.

Dr Graham Phillips: You can, I can see you through them!
They are incredibly fine. How many slivers would be in there?

Professor Andrew Blakers: There are 7 or 800 in there. And in a larger wafer with a finer pitch you might have a several thousand.

Dr Graham Phillips: Really! So you’ve essentially got 800 solar cells in here.

Professor Andrew Blakers: That’s right.

Dr Graham Phillips: Compared to one of these is normally a solar cell. That’s remarkable.

Narration: But how do you assemble all those fiddly slivers into a solar panel? In the lab it’s by hand, but the excitement of the project seems to get Vernie through the tedious work.

Dr Vernie Everett: I get into trouble because I don’t regard it as work. You know I come in here to have fun. And it’s been very rewarding.

Narration: Each sliver not only has to be glued in place, but has to be electrically connected to its neighbour, and then wires added to extract the electricity.

This solar bank has a 25 cells. It will produce the same power as standard solar, but using only a fraction of expensive pure silicon.

Dr Graham Phillips: Now sliver cells not only promise cheaper power, they’ll also allow new applications. For example, here is your conventional solar cell. Now if you try to bend that in any way it breaks. It’s extremely fragile. Where as the sliver cells, as you can see are highly flexible. Now that means you could build these into fabric for example. So put an array together like this nice and flexible that could be built into your shirt and you could charge your ipod, or mobile phone. It’d be permanently charged, no need to use the mains any more.

Another application is the slivers can be spaced apart and mounted on glass, creating a transparent solar cell.
Now these can be put into a building’s windows for example, to generate power.

Narration: Now, in case you’re thinking this is all pie in the sky, one of Australia’s largest utility companies has already built a pilot factory.

Tony Wood: Clearly were very excited by the potential of the technology. We’re now coming to the order of 40 million dollars Australian in the total infrastructure here. And we wouldn’t be doing that if we weren’t seeing that this technology really did have significant long-term potential.

Narration: The mass manufacture requires a very high tech facility, parts of the clean rooms are 100 million times cleaner than a normal lab.

And no hand assembly here. Instead a roomful of robots do the work.

And this is what completed sliver solar panels look like.

Another advantage they have is, if they’re partially shaded they still produce power. Unlike conventional panels which shut down with even with a little shade covering them.

The cost of solar is measured is the number of years of free electricity you need to pay off the installation. Today it’s about 20. With mass-produced sliver cells it could be just 5 to 7 years.

Tony Wood: We would expect to see commercial panels of the size that would be used in a domestic situation over the next 12 months or so. Now initially we’ll be putting them into the market in very carefully selected trials, to make sure the things work properly, that there’s no problems, but in the next few years you’ll certainly see these deployed in Australia and overseas.

Dr Vernie Everett: There is no single solution to energy supply problems of the world or greenhouse. But solar based on sliver technology can play a really important part.

Via: ABC.net.au