Michael Foster
Sat, 03 May 2008 18:56:45 -0700
It's so much fun to hear all you folks speculate on what's happening in this
particular field. First, no one or no company has "beat me to the punch" in
using fresnel lenses to concentrate sunlight for a photovoltaic system. This is
an old and obvious idea, newly revived because of the run up in world energy
prices and the soon to be dead issue of global warming. The development of new
photovoltaics of different types specifically designed for high concentration
is another factor.
The company I own has simply and inadvertantly become the largest and most cost
effective manufacturer of fresnel lenses in the world. My manufacturing
capacity for such lenses dwarfs that of the rest of the world combined.
Virtually every company involved in concentrator photovoltaic schemes has
contacted me about this. The conventional method of manufacturing fresnels,
compression molding of polymethyl methacrylate (PMMA) is slow and far more
expensive that the continuous roll method I use. Furthermore PMMA lenses have a
limited life in the sun and are sensitive to humidity changes. They craze and
go milky in short order. They buckle and warp and are difficult to keep at
optimum focus. Other thermoplastics can be used, but the cost is even higher,
the cycle times even slower, and the optical transmission not as good.
Just last week, I was contacted by a consulting firm hired by a company who
wants to set up large photovoltaic "farms" with the idea of generating
commercial quantities of electricity. They gave broad hints about the company
being financed by the recent round of venture capital (nearly $700 million)
floated by Algore and his new friends. Who knows what's going on here, but
their main concern was could somebody produce 20,000 square meters per month.
When I told the guy who called I could do that in a few hours, he damn near had
an orgasm.
This idea really pencils out for the photovoltaic production of electricity on
a number of counts. Primarily, the amount of expensive photovoltaic material is
greatly reduced, down to about 0.1% of non-concentrated flat panels.
Photovoltaics designed for high concentration are approaching 50% in conversion
efficiency, a figure flat panels will probably never reach. The main feature of
such systems normally pointed out as disadvantage, tracking the sun, more or
less pays for itself in having more hours per day of optimum output. Even flat
panels would have a higher daily output if they tracked.
I have no idea if someone will step up the plate and start giving me large
orders for my concentrator fresnel arrays, but I'm proud of what I've done and
I hope it has some practical use.
Meanwhile these things find broader application for making pretty cosmetic
packages. Oh, well.
M.
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