In 2008 the Washington Post ran a report about serious pollution caused by silicon tetrachloride (SiCl4) discharged from a polysilicon (poly-Si) plant in Henan Province, China. Since then, China's authorities have raised the threshold for the establishment of poly-Si plants. By contrast, poly-Si plants are still highly regarded by the Taiwan government, as evidenced by the attendance of ranking government officials in ground-breaking ceremonies for poly-Si projects. One cannot help but wonder whether government officials are fully aware of the threat of poly-Si projects on the environment.
The China government considers poly-Si manufacturing an industry of high pollution and high energy consumption. Therefore, it has erected ever higher entry thresholds for industry players, including minimum annual output of 3,000 tons and denial of loans for those with process technology not conforming to environmental standards. In 2011, it has suspended the issuance of licenses for new projects, until a new strategy has been formed.
The major concern about poly-Si production is the emission of massive amounts of SiCl4, a highly toxic substance which is hazardous to eyes, the respiratory system and skin. Heated or dissolved in water, it will discharge toxic and corrosive smoke.
With the rapid emergence of the PV industry, China has invested massively in the manufacturing of poly-Si, leading to the outbreak of a litany of SiCl4 pollution incidents. The magnitude of the problem may be much larger than the appearance, as many cases have not made headlines.
Poly-Si byproducts and materials pose environmental hazard not only in China but also in established markets in Europe and the US. The Washington Post report uncovered the dumping of SiCl4 in the neighborhood by Henan's Luoyang Zhonggui, rendering the farmland inarable. In 2010, Chinese media reported that in the neighborhood of a poly-Si plant in Shizuishan, Ningxia Province, land became barren due to pollution by SiCl4 and hydrogen chloride. In October 2010, neighboring residents protested the emission of gaseous pollution by a poly-Si plant of Yingli Group. There have also been reports from the China media about toxic emissions from LDK Solar of Jiangxi Province, with its employees among casualties of the pollution.
Taiwan's solar cells and silicon wafers have a solid presence in the global PV industry. Its players are major contract manufacturers for solar cell vendors worldwide. But Taiwan manufacturers have often suffered shortages of materials.
Aware of the importance of self-sufficiency, Taiwan PV makers have been aggressively investing in poly-Si production: Taiwan Polysilicon, a joint venture of LCY Chemical and Everlight; Powertec Energy, a joint venture of Top Green Energy, Walsin Lihwa, Sino American Silicon Products (SAS), and United Microelectronics Corporation (UMC); and Shihlien, a joint venture between Taiwan Glass and Green Energy Technology. AU Optronics (AUO) also has plans to set up a ploy-Si plant in a coastal industrial zone in Changhwa, central Taiwan, and the Formosa Plastics Group reportedly is also mulling to build one in Taiwan. All these poly-Si projects would translate into 1.43 plants every 10,000 square kilometers, making Taiwan a country boasting the highest density of poly-Si plants in the world.
According to the Chinese media, China now has 41 poly-Si plants or 0.04 per 10,000 square kilometers, South Korea has six poly-Si plants or 0.61 per 10,000 square kilometers, and Japan has four, or 0.11 per 10,000 square kilometers. In view of its dense population and limited land, Taiwan will be especially vulnerable to public hazards and pollution problems caused by poly-Si manufacturing.
New poly-Si plants boast cutting-edge technologies that are claimed to be able to recycle SiCl4 and thereby minimize pollution. Such claims do not seem all that convincing, judging from the aforementioned pollution cases.