More than ever before, people are aware of the need to ditch petroleum and coal as our main energy sources and turn to renewable sources.  Solar is often the first thing people think of as a solution, with the Sun and it's practically infinite energy as the savior of our energy woes.  Of all the proposed alternative energy options (solar, wind, tide, geothermal, biofuel, hydro), solar is the only one we the consumers can actually use to produce energy ourselves.  It is a great way to make a quantifiable difference for the environment, and the installation of solar panels in homes has taken off in recent years.  However, there is one huge problem holding solar back, and I'm sure it comes as no surprise: cost.  Residential systems range from $10k-$100k, which means a lot of us who would love to install solar, knowing it is a great long term investment that lowers energy bills and increases home value, simply cannot afford to.  

In this market-driven world, the future of all alternative energies depends on reducing their costs to the point where they can compete against fossil fuels.  Now, thanks to a solar energy start-up from Silicon Valley, the epicenter of American technological development and advancements, solar is about to become much cheaper, with the future possibility of prices that match petroleum and coal.  

Nanosolar was founded in 2002 by two Stanford grads with the goal of reducing the cost of solar by an entire order of magnitude.  In 2007, they sent out their first shipment of panels to a power plant in Germany.  In between, they received lots of hype and expectations along with over $300 million in investments.  The reason for all the attention is  Nanosolar's technique of printing onto thin-film,  a departure from the conventional thick, silicon-based photovoltaics that drastically cuts costs.
 
The panels are basically thin sheets of metal sprayed with a nanoparticle ink made up of copper indium gallium diselenide (CIGD).  The ink replaces the much more expensive silicon as the photovoltaic material, with the thin metal sheet acting as the conducting substrate.  The resulting panel can be printed on long sheets, much like a newspaper, in a process that is fast, simple and cheap.  It all adds up to a solar panel that costs much less than typical photovoltaics.  See a video of the process here.

The result is energy that costs just less than $1 per watt, compared to an average cost for solar energy of $4.83 per watt.  The panels are also much lighter and can be rolled up, making transport easier and cheaper, and they can be bent, curved, and cut to fit whatever shape is necessary.  

In 2007, the world's largest factory for producing solar cells was put into operation by Nanosolar in San Jose, CA.  They have since sold out all orders through the end of 2008.  

The technology is already in the marketplace and can be considered a resounding success.  The emphasis for Nanosolar in the future will be on expanding production capacities, which their new plant in Germany will help them with, and to increase the efficiency of their cells. Nanosolar CEO Martin Roscheisen says that his company's cells operate in the "9 to 10 percent range and that the company expects it can reach 15 percent efficiency ultimately.  The best silicon cells reach 20% by comparison.  

Nanosolar also must strive to keep ahead of the competition, as other companies are beginning to manufacture thin-film solar panels with the hopes of improving on Nanosolar's costs and efficiency.  Competitors include Global Solar, HelioVolt Corp., and Solyndra.    

The production of photovoltaics has been doubling every two years since 2002, according to the Earth Policy Institute.  That data, combined with the Prometheus Institute for Sustainable Development's prediction that in 2010 between 20-30% of solar will be thin-film, bodes well for the future of the industry.  

For now though, thin-film solar panels are only available for use in power plants and wholesale to commercial partners.  But with its low-cost, light weight, and flexibility, it is not hard to imagine that in a few years thin-film solar panels will be an affordable option anyone can install in their home.