Solar Cells Info

By Richard Dobson /Additional reporting by Baker Li
Taipei, Dec 6, 2007
Source: Reuters UK
http://uk.reuters.com/article/environmentNews/idUKTP33777420071206

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.” The pay-off is in the lower cost.

Thin film module prices were being sold in Europe in November for $3.69 per watt compared to $4.29 per watt for the lowest priced traditional multicrystalline module of similar power sold in the United States, according to a Solarbuzz survey.   “The lower retail prices are making companies interested in the technology as an alternative. However, there is a large capital expenditure to build a thin-film plant and the solar power conversion rates are low,” according to KGI Securities researchers in Taipei. “It’s still too early to know if it can be a profitable technology in the future, as we’ll have to see if the conversion rate can be boosted and also how many players enter the market, which will affect competitiveness,” said KGI.

Obstacles aside, many believe that thin-film efficiency will steadily rise, possibly reaching 15 percent, with improving technology to take a bigger share of the solar energy market. Thin-film solar cells could account for up to 30 percent of the global solar cell market by 2010, from around 7 percent in 2006, according to estimates compiled by Taiwan’s E-Ton Solar.

Japanese electronics maker Sharp Corp plans to boost its thin-film solar cell production capacity from 15 megawatts per year to 1,000 megawatts (MW) by 2010 with the construction of a massive plant in Sakai City. No investment figure was available from Sharp, but rising costs of silicon are making the new technology more attractive.

The lure of thin film is spreading, with firms across the industry getting involved with the technology, including Taiwan’s Motech Industries, China’s Suntech Power Holdings and Germany’s SCHOTT Solar. Chi Mei Optoelectronics, Taiwan’s No. 2 maker of LCD panels, also recently said it was entering the thin-film business. Germany’s Q-Cells has invested aggressively in companies producing or planning to produce thin-film technologies, buying as Calyxo GMBH and Brilliant 234 GMBH, with annual capacity of 25 MW and 24 MW, respectively, by the first quarter of 2008.