Solar Silicon Shortage

Power from the sun may help with the world’s energy crisis, but at the moment, the demand for solar power is resulting in a shortage of silicon.

Global government mandates to reduce dependence on fossil fuels have resulted in an expanding solar market. This growth, according to the presentation “Understanding Photovoltaics — from Raw Materials to Systems,” presented at the iSuppli European briefing in April 2008, is straining current supplies of polysilicon. Henning Wicht, senior director and principal analyst of microelectromechanical systems and photovoltaics for iSuppli, delivered the report.

The summary forecasts that, in 2010, the photovoltaic industry will have the potential to manufacture cells and modules with a production capacity of up to 14 GW of photovoltaic systems, whereas there will be enough silicon to produce only 8 to 10 GW (Figure 1).

Figure 1. Cells and modules can produce up to 14 GW of photovoltaic power; however, the polysilicon supply currently is only 8 to 10 GW of power because of capacity limits.

As sources for solar silicon have been depleted, prices have gone up, according to Wicht. Polysilicon suppliers are demanding 10 to 20 per cent of their total contract costs up-front, which puts more pressure on photovoltaic manufacturers.

As a result, companies such as SolarWorld AG of Bonn are partnering with chemical manufacturers such as Evonik Industries AG of Essen, also of Germany, to produce silicon expressly for solar use. Solar-grade silicon does not fulfil the requirements of electronic-grade silicon in terms of purity. The advantage, however, is that solar-grade silicon is produced at lower cost.

One response of photovoltaic cell producers is to turn to thin films, which can be deposited on glass, steel or polymer foils without any — or with only a small percentage of — silicon. Silicon cell manufacturers increasingly are investing in thin-film technologies in parallel with polysilicon. Thin-film solar cells are less efficient than crystalline silicon, yet they are less expensive to produce.

Despite the increased energy production from solar technologies, prices still are high for the end user. Wicht recommends that industries focus on reducing costs and on turning out high-quality products with the promise of long-term use, motivating investors as well as national governments to support energy production from this most unfailing source.