SOURCE: Enpower Management Corp.

November 14, 2012 08:00 ET

Cost Breakthrough in Production of Ultra-Pure Polysilicon

Renewable Alternative Offers a Sustainable Replacement for Energy and Chemically Intensive Methods

SAN RAMON, CA--(Marketwire - November 14, 2012) -  A research collaboration between Mayaterials, Inc. and Wadham Energy LP, processing agricultural waste, has developed an environmentally friendly and more cost effective route to producing ultra-pure polysilicon feedstock for use in photovoltaic (PV) and electronics applications than any other approach to date.

This development comes as a result of years of research funded by the U.S. Department of Energy (DOE) and Wadham Energy LP. The project has recently produced polysilicon feedstock of approximately 6N purity (99.9999%) using rice hull ash. Dr. Richard Laine, CEO of Mayaterials, says, "We have made great progress at the pre-pilot level achieving ultra-pure silicon, and look forward to proving out the technology at an industrial scale." A recent production run with rice hull ash, targeting the semiconductor industry SEMI III standard for PV grade silicon, produced 600 g of silicon with impurity levels of:

    Al   B   Ca   Cr   Cu   Fe   Mg   Mn   K   Na   P   Purity
ppm*   ND   0.1   0.2   0.05   ND   2.0   ND   0.2   0.2   ND   ND   99.9997%
 *by weight

An independent engineering evaluation of the Mayaterials process estimates that a commercial plant producing more than 40 tonnes/day would have a capital cost of approximately $24/kg and a variable cost of $5/kg. Ed Tomeo, President and CEO of the general partner for Wadham Energy LP, says, "Our understanding is that this represents a 70% reduction in capital and a 60% reduction in operating costs compared to conventional methods for producing ultra-pure polysilicon. This could be a game-changing technology for the industry, helping to drive down the costs of PV modules to well below $1.00/watt." 

Low production costs are attributable to several factors. First, rice plants do not absorb heavy metals from the soil that would normally be found in mined quartz, thus the ash requires much less purification. Second, rice hull ash is predominantly amorphous silica, providing a feedstock from which impurities can be more easily removed. Third, combustion of the rice hulls to produce electricity produces an ash containing valuable residual carbon, a necessary feedstock when producing silicon in an electric arc furnace. Fourth, the Mayaterials process does not require the costly and toxic chemicals currently used by major conventional polysilicon manufacturers. Consequently, the costs of raw material, purification, managing dangerous chemicals and protecting the environment are significantly reduced.

Mayaterials, Inc. and Wadham Energy LP are presently seeking financial or strategic partners to fund additional research and a $5M bio-sourced polysilicon production pilot plant. Interested parties are invited to contact us about this opportunity. Extensive research information, including applicability to other bio-sourced materials, an independent engineer's report, DOE filings, economic modeling and intellectual property status are available for review. Questions from the press are also welcomed.

Mayaterials, Inc., founded in 2003, develops process solutions for the production of silicon containing materials and chemicals. In addition to the novel silicon process, Mayaterials also produces low-cost silicas for many diverse commercial applications including high quality insulation, food additives (toothpaste), polymer additives (rubber tires), optical grade lenses (cameras), and many more. Opportunities exist with these products as well. 

Wadham Energy LP, is an independent energy company whose sole operating asset is a 26.5 MW rice hull fired steam-electric biomass generating plant located in Colusa County, California. The facility consumes more than 190,000 tonnes of rice hulls per year. The facility is a highly successful turnaround by Enpower Management Corp. of San Ramon, California, has been in continuous commercial operation since 1988 and is deemed a "renewable resource" under California law. Wadham Energy LP produces approximately 40,000 tonnes per year of highly reactive, 90% amorphous silica, rice hull ash.

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