| Silicon Technology |
Si TechnologyA major bottleneck in the value chain of quartzite to silicon-based PV cells is the purification of Si from metallurgic grade (MG), typically 99.6% pure, to solar grade (SG) feedstock, which is 99.9999% pure. Globally, the six major players in the Si feedstock market are producers of electronic grade (EG) silicon, which requires even higher standards of purity and morphology. Historically, the semiconductor industry has been the major market for the Si feedstock suppliers and the photovoltaic industry was a niche market whose needs were met with surplus or “off-spec” EG-Si. With the explosive growth of the photovoltaic industry in recent years, the scrap EG-Si supply of Si feedstock is no longer sufficient to meet demand, and spot market prices for EG-Si have shot up to over $100/kg. The Si feedstock industry has responded by running Si refining plants at full capacity and securing long term contracts with the largest ingot/wafer manufacturers. Due to the nature of the purification process, however, major plant expansion requires long lead times and intensive capital investment, both lacking in a risk-adverse industry suffering from past downturns in the electronics business.
As a result, PV manufacturers are scrambling to secure Si feedstock supply, anticipated to remain tight for the next 3-5 years, and to reduce the amount of Si used in PV cells, thereby keeping a lid on manufacturing costs. The ARISE approach is to address both of these critical needs by building an integrated PV silicon wafer pilot plant which will incorporate key innovations in two initial steps of the PV value chain: a process for producing SG-Si feedstock and silicon recovery technology that reduces waste in the ingot/wafer slicing process. The main reasons ARISE is investigating silicon feedstock are to: 1. Remove a potential barrier to growth2. Develop an approach that could generate significant patentable technology 3. Take advantage of Canada’s low cost electricity rates in certain jurisdictions 4. Leverage a component of the value chain that has high margins 5. Capitalize on interest from the government Silicon Feedstock Pilot PlantARISE has investigated various existing silicon feedstock approaches and plans to commercialize a process that was successfully demonstrated at the lab prototype stage but never taken into production. This process is much simpler and potentially much less capital intensive than those typically used in the Si feedstock industry. Plans to commercialize the Si feedstock technology began in earnest in September 2005, with an ARISE application to the Sustainable Development Technology Corporation (SDTC) for a $6.5 million grant to build a silicon feedstock pilot plant on the north campus of the University of Waterloo. This proposal was ultimately successful in gaining SDTC approval, as announced on July 6, 2006. In order to fulfill our obligations under the SDTC agreement, ARISE provided seed funding to demonstrate the scalability of the process at the University of Toronto starting in January 2006. Preliminary results have proven successful, and ARISE is continuing to build out the project plan, gathering a consortium of partners to raise the $10 - $15 million of cash and in-kind support needed over the three year pilot plant program. More details will become available once the consortium partnership is in place and a formal contribution agreement with SDTC is signed, expected in late 2006. |
