TODAY, SOLAR ENERGY SUPPLIES just 1.5 GW — less than one per cent of the world's total energy needs. Estimates of how big solar will become, and what percentage of demand it can meet, vary enormously. "Five per cent of the renewable energy pie," predicts a cautious Mints. "Fifty per cent of the world's electricity in 2050," reckons an optimistic Blakers.
But the truth is, no one knows what will happen. Much will depend on the fast-changing politics of climate change. Even in Canberra, doors that have long remained closed to solar researchers have lately started to swing open. What can be said with certainty is that, at long last, the solar industry has momentum and the money to maintain it.
Throughout its history, the photovoltaic business has been the poor cousin, forced to feed off scraps from the semiconductor industry. But while the chip makers don't care how much they pay for silicon, for the panel makers, the price of their raw material is the key metric.
Now, flush with venture capital and profits, the photovoltaic folks can afford to develop processes and equipment specific to their needs. For example, Yerkes, the solar panel pioneer, is today chief technology officer for California-based Solaicx. The company's goal is to change the economics of silicon wafer production, attacking the biggest obstacle to the widescale adoption of solar power: cost.
The conventional method of making solar-grade silicon is to grow individual ingots, then saw them up into wafers. Solaicx has developed a continuous crystal grower that Yerkes says can crank out ingots like sausages. One machine is capable of growing five megawatts' worth of 15 cm-diameter ingots every year.
The company's first grower is about to go into continuous 24-hour operation, making Solaicx one of the few firms in Silicon Valley that actually produces silicon. More machines will enter service next year at a new facility in Oregon. Yerkes claims that the technology has the potential to reduce the cost of silicon wafers — which account for about half the price of a solar panel — by 75 per cent.
Some people wonder why it has taken solar power such a long time to reach critical mass. As he looks back on three and a half decades of hard-won progress in solar cells, Yerkes, now 72, disagrees. "I don't think it has taken very long," he says. "Compared to my genes and your genes and that sort of thing, it's happening almost instantaneously."
Bob Johnstone is a science and technology writer based in Melbourne.
