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In the past few years, solar panel technology has
(economically speaking) improved by leaps and bounds. Solar companies around
the world have been able to drive down the costs of materials and products by making
manufacturing processes more efficient.
But some smaller startup solar companies are looking to
compete with the large silicon solar panel industry using other types of solar
technology.
Solar Panels for
Windows
Heliatek, a startup from Dresden, Germany, has developed
solar panels made of small, organic molecules deposited on polyester
films. The panels are flexible and are
much lighter than traditional silicon panels. Heliatek is looking to integrate
these panels into various forms and applications. A building materials company
is helping integrate these panels into concrete facades, while another
manufacturer is helping incorporate transparent versions into windows.
(Flexible, lightweight solar panel from Heliatek - Credit: Heliatek)
Organic solar cell technology has existed for decades. The
advantage is that they can be cheaply printed, allowing them to be produced at
a very low cost. But the cells, made from long polymer chains, suffer from much
lower efficiencies and lifetimes than silicon-based cells. Heliatek's cells,
which use oligomers instead of polymers, have improved efficiencies and are
predicted to be as long lasting as conventional solar cells.
These panels may be convenient for buildings looking (or
required) to be more energy efficient and sustainable; they encourage builders
to incorporate them in windows and facades. Installing these panels may be
cheaper and easier than traditional panels that require more hardware and
effort for placing on a roof.
High Efficiency Cells
A small but well-financed startup company called Alta
Devices is working on another type of solar cell technology. They are focused
on using gallium arsenide instead of silicon as the semiconductor material for
the cells. The material is a much more effective for capturing sunlight, so
much so that a thin layer of it (only micrometers thick) recently set a record
for photovoltaic efficiency at 28.3 percent.
The efficiency of gallium arsenide is not new - it has been
the primary material used in construction solar cells for spacecraft and
satellites. In addition to its high efficiencies, the material is also less
sensitive to heat than solar cells, meaning it maintains performance over a
larger temperature range than silicon.
The problem is that gallium arsenide is very expensive;
films of the material tend to be fragile and difficult to fabricate. Alta
Devices' innovation comes through techniques designed to lower manufacturing
costs, boost performance, and ultimately make these cells economical on a large
scale. One technique allows semiconductors to be grown epitaxially without
being prone to cracking. In addition, work done by Alta researchers has led to
the design of cells which take advantage of "photon recycling" to further
increase efficiencies.
Learning from
Solyndra
Both Heliatek and Alta Devices have a ways to go if they
plan to compete with established silicon-based companies in the solar cell
marketplace. The fact that prices are going down makes it all the harder for
new companies to grab a piece of the market. And of course, the "go big or go
home" startup failure that was Solyndra is still looming in the minds of
investors.
Perhaps it's no coincidence that the headquarters of Alta
Devices is in Silicon Valley in the same office of the infamous solar company.
Alta's CEO, Christopher Norris, says his company is taking a much more
methodical approach to scaling up, hoping to ensure that their inventions are
economically feasible on a pilot-scale plant before shelling out hundreds of millions of dollars in investment
capital.
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