But how fairly are they in tabulating the real amount of energy it takes
to build them? It was a few years ago that I had a debate about this
with somebody else and none of the manufactures had published any
information that included all of the energy that it takes, and the
amounts produced were very optinistic for most of the world.
Solarex's buildings in Frederic MD, have huge banks of cells, but
even if that plant is off the grid, it is not where most of the
energy for manufacturing is used. Smelting Si and growing the
crystals takes a lot. Making glass and aluminum for the frames
takes a lot. Adding the final layers to a waffer and wiring it
up does not take much energy, and I'm willing to bet that it's the
only step they measure in the 2-3 year pay back figure.
And that's not to mention the deadly organic acids used. . . . .
==>paul
At 02:03 AM 12/18/1999 -0600, you wrote:
>The latest figure I've seen is that a PV module can generate as much
>power as it took to produce it in as little as 2-3 years for the most
>efficient modules. With a life expectancy of at least 20-25 years,
>that's not a bad payback. I'll try to find the reference if you'd like.
>
>Doug Fields
>
