B a h r a m e r a d: Nanosolar’s Breakthrough

Sunday, November 25, 2007

Nanosolar’s Breakthrough - Solar Now Cheaper than Coal

November 23, 2007 : Filed under CleanTech - Solar, Energy by Jessica Hunt

Their mission: to deliver cost-efficient solar electricity. The Nanosolar company was founded in 2002 and is working to build the world’s largest solar cell factory in California and the world’s largest panel-assembly factory in Germany. They have successfully created a solar coating that is the most cost-efficient solar energy source ever. Their PowerSheet cells contrast the current solar technology systems by reducing the cost of production from $3 a watt to a mere 30 cents per watt. This makes, for the first time in history, solar power cheaper than burning coal.

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These coatings are as thin as a layer of paint and can transfer sunlight to power at amazing efficiency. Although the underlying technology has been around for years, Nanosolar has created the actual technology to manufacture and mass produce the solar sheets. The Nanosolar plant in San Jose, once in full production in 2008, will be capable of producing 430 megawatts per year. This is more than the combined total of every other solar manufacturer in the U.S.

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Nano particles
Nanosolar, Inc. prides themselves on being the “Third Wave” of solar technology. The “First Wave” began over three decades ago with the introduction of silicon wafer based solar cells. This technology bore high material and production costs with poor capital efficiency. Silicon does not absorb light very well and therefore, the silicon wafers must be very thick. Also, the wafers are extremely fragile. Their need for intricate handling complicates processing all the way up to the final panel product. The “Second Wave” came about a decade ago with the first “thin-film” solar cells. This established that a cell 100 times thinner than the solar wafers can work just as well. However, this process also has its setbacks. First, the cells semiconductor was deposited using slow and expensive high-vacuum based processes. Secondly, the thin films were deposited directly on glass as a substrate. This eliminated the possibilities of: Using a conductive substrate directly as electrode (The Nanosolar cells work on a metal foil substrate, or semiconductor, instead of the stainless steel or glass substrate. The metal foil semiconductor creates an increase in yield of 20%); Achieving a low-cost top electrode of high performance (An electrode is a conductor through which electricity flows.); Employing the yield and performance advantages of individual cell matching & sorting (The effect of electrical mismatch per cell leads to greater losses per panel as a result, and panel yield and efficiency distribution suffer: A bad cell results in a bad panel with thin-film-on-glass technology; but with a cell-sorting technology, only that cell will be a loss); Employing high-yield continuous roll-to-roll processing (Roll-to-roll processing allows large quantities of material to be processed with equipment that leaves a small footprint); Developing high-power high-current panels with lower balance-of-system cost {Nanosolar.com}. To put it simply, the production cost was still too high and the product did not yield a high enough output of energy. Nanosolar, however, brings together the entire conjunction of all seven areas of innovation which delivers a dramatic improvement in cost efficiency, yield and throughput of the production of much thinner cells than ever before.

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