AT AROUND NOON on 26 July 2006, a watershed event occurred in Germany. For the first time ever, the cost of electricity generated from conventional sources such as nuclear exceeded that for energy generated from the Sun during a period of peak demand.
Now, as policy makers wake up to the implications of global warming, other European countries — Spain, Italy, Portugal and Greece as well as the United States, in particular California — are emulating the German example. As manufacturing volumes increase, so the price of solar panels will drop, by 20 per cent for each doubling in production.
Meanwhile, the introduction of taxes on emissions and expensive palliative measures such as 'clean coal' technologies and carbon sequestration means that the cost of fossil fuels will inevitably rise.
Today, the solar power industry is basking in the prospect of double-digit growth for years to come. In fact, demand is so high that supplies of silicon feedstock are drying up. Crystalline silicon is the material of choice for more than 90 per cent of photovoltaic panels. The solar boom is sucking up production, and the price of the raw material has jumped from US$65 a kilogram to as high as US$400.
Boosting production of purified silicon to meet demand is not trivial, as it involves massive capital outlays. Such investments are underway, but it may take silicon producers several years to catch up with demand.
The unhappy result of the silicon shortage is that, instead of falling, prices of solar panels have actually been rising. This has opened a window of opportunity for innovative photovoltaic technologies that use less silicon — or none at all. As it happens, Australian researchers and firms are pioneering both approaches.
IT HAS TAKEN SOLAR POWER over 30 years to work its way toward the mainstream. The photovoltaic cell was invented at Bell Laboratories in the U.S. in 1954, and solar's first applications were extraterrestial, powering the likes of communications satellites and lunar modules. Space panels were hand-crafted like jewellery; price was no object.
The origin of the modern photovoltaic industry dates back to 1975, when Bill Yerkes founded Solar Technology International (which became Arco Solar) to address terrestrial markets, such as charging batteries. Yerkes was responsible for two major innovations: he stuck silicon wafers on the back of glass, protecting the cells and making his panels almost indestructible. Second, he developed an inexpensive screen-printing technique for depositing metal contacts.
Since then, developments in good old flatplate solar technology have mostly been a matter of eking out incremental improvements in efficiency. Today's best panels are capable of converting around 22 per cent of sunlight into energy.
Over the years, it has been repeatedly demonstrated that, in solar cells, there are no magic bullets. "It's very hard to make this stuff work," Mints says. "It has to sit out in the Sun for 20, 25 years. I mean, how many other products do you know that can do that?" The fact of the matter is that commercialising solar products takes money and time. As one long-suffering solar industry survivor puts it, "Reality is a bitch."
In 2000, Andrew Blakers and Klaus Weber of the Centre for Sustainable Energy at the Australian National University in Canberra came up with an ingenious new idea for reducing the amount of silicon used, and hence the cost of solar cells.
Instead of using silicon wafers sawn from the ingot, they took the process a step further — into the third dimension — and used micromachining to slice up wafers into a thousand narrow rectangular slivers, each just 0.05 mm thick. Lifting the slivers out to form a cell is, Blakers insists, a simple matter. A single 15 cm wafer yields enough slivers to cover a square metre.
The university licensed the technology to Australia's Origin Energy, which invested over A$30 million in the construction of a pilot plant in South Australia to manufacture sliver cell panels. In August 2006, amid much hoopla, the then Australian Prime Minister John Howard announced the launch of a A$75 million initiative to build 'solar cities'. In the first of these, in North Adelaide, 1,700 homes will be equipped with solar panels made in Australia by BP and Origin Energy.
