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The alternatives

Silicon cells, which have dominated the market since its commercial launch in the 1950s, may still represent viable competition to Thin Film technology. Silicon cells have an average cell conversion efficiency of around 16-20% while Thin Film CdTe panels are only 10.6% efficient. Due to the enormous growth experienced by the Solar industry in recent years, the price of raw silicon peaked in 2008 at $1000/kg which has kept the manufacturing cost of silicon based cells fluctuating between $3 and $4 per watt. Now that increased silicon production capacity has caught up with demand from the solar cell industry and the Global financial downturn has reduced demand from the computer chip industry, the price of silicon has dropped to under $40/kg. The result - we can expect to see substantial deductions in the cost of silicon solar cells in the near future.

There are also other technologies on the horizon including cells based on copper indium gallium ­diselenide (CIGS), silicon on glass, and the combination of ­germanium, gallium arsenide, and gallium ­indium phosphide all of which are competing to lower the cost of solar cells.

Leading the way in this space is Nanosolar Inc., a private Palo Alto company founded in 2001.

In the course of their work, Nanosolar engineers developed a way to imbed a compound called CIGS into thin polymer films. This metallic compound is the key to the entire process. It contains copper, indium, gallium and selenium. Without these metals the production of these films is impossible.

Last June Nanosolar announced that they were going to build the world’s largest factory for making solar power cells.

Once started, the Nanosolar plant will produce a new type of material that will blow away the existing silicon based panels at 1/10 of the cost. And in doing so, this new technology promises to make solar competitive with fossil based fuels- even if those fuels drop drastically in prices.

Even more stunning was the capacity of the plant itself. According to Nanosolar’s CEO, Martin Roschesien, the plant will turn out enough solar cells each year to generate 430 megawatts. That’s enough electricity to power about 325,000 homes.

With these two companies and others like them making such advances, it is easy to see why “green” writers are calling them “the solar equivalent of the Holy Grail.”