Thin-film solar sheets seek time in the sun

By Richard Dobson

TAIPEI (Reuters) - Soaring oil prices approaching $100 a barrel are fueling a sleek new kind of solar technology that could some day set skyscrapers and high-rise apartment windows quietly buzzing with renewable energy production.

The emerging technology uses thin films mounted on the glass windows of skyscrapers and other surfaces to harness the sun's power.

It's more aesthetic and cheaper than the bulkier conventional solar cells made from polycrystalline silicon whose supplies have tightened and prices have risen as solar energy has taken off.

Current thin-film surfaces generate less power per area than traditional polysilicon modules, but they also use less polysilicon then conventional cells making them attractive to some of the world's top solar panel makers.

"Silicon is in short supply. This is a very critical issue so at the moment we are focusing on thin-film investment," said Tatsuo Saga, deputy general manager of Japan's Sharp Corp solar systems, one of the world's leading solar panel makers.

Thin-film is cheaper to produce, more durable and more aesthetic than bulky solar panels, which are often accused of being eyesores. The transparent sheets can serve as facades for skyscrapers and housing roofs where they absorb the sun's rays and turn it into energy.

"One big advantage of the thin film products is that they don't have to use too many raw materials and they are much cheaper than silicon solar wafers," said Robin Cheng, an analyst at UBS Securities.

The potential has attracted major solar energy players such as German-based Q-Cells AG as well as the likes of industrial giants like Applied Materials Inc, the world's biggest maker of semiconductor manufacturing equipment, which see big growth potential in thin-film machinery.

Thin film solar cells use much less silicon -- which accounts for between 40-50 percent of a module's costs -- than traditional crystalline silicon cells which require 200 times more silicon.

Thin film's advantage comes in its low price in terms of production costs as well as its ability to serve as attractive transparent panels on large buildings.

"We are sure in the years to come we'll have the same sized (products) as architectural glass," said Winfried Hoffmann chief technology officer of Applied Materials' solar business group at an event in Taipei.

HALF-BAKED?

Despite thin film's promise, the technology still faces many challenges, said Jerry Yang, vice president of United Solar Ovonic Corp, a U.S. company.

In terms of generating efficiency rates, or the percentage amount of power made from the available sunlight, thin film modules average around 6 percent. That is less than half of the 15 percent for traditional crystalline silicon cells, according to Solarbuzz LLC, a solar energy research and consulting company.

"A lot of work needs to be done to expand the market, reduce costs and improve the efficiency," said Yang. "Our product efficiency is 8 percent. Within a short time we will reach 8.5 or even 9 percent. That's our goal."