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Silicon for solar cells at low costs on an intermediate scale

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Crystallising Europe's silicon supply for solar power

Crystalline silicon is the dominant material for producing photovoltaic (PV) solar cells, although, as demand grows, supplies of this scarce material will become strained. One solution developed by an EU-funded project is to extract crystalline silicon from quartz.


Solar technology has taken off across Europe in a big way in recent years – and this trend is set to rise. Crystalline silicon is among the main materials used to produce PV cells, and will remain the dominant material for the foreseeable future. In fact, demand is estimated to grow at 30 % per year. The costs of crystalline PVs have dropped massively since the 1970s – they are now about 100th of the price per watt generated. Nevertheless, 17 % of module costs relate to feedstock, and even though cells will become more efficient and thinner, demand is bound to burgeon. It was projected that demand would grow from 7 000 metric tonnes to some 20 000 metric tonnes annually by 2010. A dedicated solar-grade silicon source is needed or growth will stagnate and feedstock prices will increase significantly, which could jeopardise compliance with EU objectives. The 'Silicon for solar cells at low costs on an intermediate scale' (SISI) project aimed to alleviate the PV industry's dependence on the conventional supply of silicon. With EU funding, the consortium explored the promising option of securing high-purity silicon through the direct carbo-thermic reduction of quartz. With partners from major European industry and institutes with expertise in ultra-high–purity quartz, SISI demonstrated an integral direct carbo-thermic route for extracting solar-grade silicon. This was achieved at an intermediate scale but could be scaled up to full industrialisation. To exploit and commercialise the knowledge developed, the SISI partners established a firm called SOLSILC Development Company (SDC). They also hammered out an intellectual property rights agreement to map out how this exploitation was to occur. After evaluating various potential partners, SDC granted a licence to an investment company and signed a long-term research and development contract to scale up the SOLSILC concept. Moreover, plans were drawn up for the development and realisation of a pilot facility. Numerous companies requested quotations for the supply of the novel solar-grade silicon. Other market players expressed their interest in being supplied with intermediate products. In addition, the partners have been conscientious about advancing the scientific case by making relevant scientific information publicly available. The technology and concept developed by SISI will help ensure the future sustainability and competitiveness of the European PV sector.

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