Hawaii
Energy Policy Forum > 2002
Articles
Thin-Film Photovoltaics
Mother Earth News
Feb/Mar 2002
Most people know solar photovoltaic
(PV) panels as large, heavy, rectangular panels mounted onto
a roof or sometimes
on a special rack with a tracking system that turns the
panels to keep them facing the sun. These older style panels
are made of crystalline or polycrystalline silicon modules.
In contrast, a new kind of PV panel is now available, called
thin-film amorphous silicon. Here's how the new thin-film
panels compare to the crystalline modules:
-
The older crystalline
and polycrystalline modules are fragile and need to be
mounted in an aluminum frame between
a layer
of glass and a stiff-bottom material. In contrast, the
newer thin-film amorphous PV panels use a thin stainless
steel
foil and a weatherproof plastic "elastomer polymer" coating.
As a result, thin-film panels are unbreakable, much lighter
and less expensive than the crystalline products, since
they don't require glass covers and metal framing.
-
The crystalline
panels lose efficiency and produce less electricity
when termperatures rise, while thin-film panels
are not bothered by hot, sunny conditions.
-
Crystalline panels
stop producing electricity when even one portion of
a panel is shaded, while thin-film panels
still produce energy when partially shaded. Thin-film
panels are also more efficient than crystalline in indirect
or
diffuse light, making expensive tracking systems
unnecessary.
-
The
production process for the thin-film panels requires
much less energy (and thus cost less) than crystalline
panels.
-
When used as roofing shingles, thin-film panels
actually are the roof, so you can save the otherwise
additional cost of regular roofing. New quick-connect features
and large
panels are making thin-film roofing faster, and
thus
less costly, to install.
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