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E-M:/ Overview of concentrator photovoltaics

Enviro-Mich message from "Lowell Prag" <lprag@mail.msen.com>


For those of you interested in photovoltaics (pv), which turns sunlight
directly into electricity, and how it can now become a common reality
every where in the USA, through new concentrator technology, below is a
repost of my email to
http://www.cichlid.com/mailman/listinfo/solar-concentrator, a technical
discussion group on concentrator pv.

This form of pv through various methods, intensifies sunlight to increase
the output of a pv cell and my repost gives a link to an excellent
overview on current concentrator pv technology.

Some facts by way of introduction to concentrator pv:

On a sunny day in Michigan, the sunlight on one square foot
has the energy of about 100 watts.

With concentrators, that can easily be increased 10 fold,
upwards to over 100 fold.

At 10 fold, a pv cell rated at x watts output in 1 sun, would now have 10x
watts output when placed in the sunlight concentrated to the equivalent of
10 suns.

There were a couple of problems with this:

Standard pv cells do not work well at the high temperatures generated by
concentrators, and standard concentrators do not work well in diffuse

Those problems have been overcome:

New pv cells developed for outer space, can operate at high temperatures
and they are multijunction pv cells which can use the energy of all areas
of the sunlight spectrum, with a new record efficiency of 34%.

New concentrator designs with special fresnel lenses, now work in diffuse
sunlight which means that they will work not only in a desert but also in

In short:

regular flat plate pv panels without concentrator technology, will soon be
displaced by concentrator pv using the new multijunction cells, and with
the very high efficiency of those cells in conjunction with the
concentrators, will produce electricity at less cost than buying it from
DTE, etc.

That is the break through that can make pv a reality everywhere in the USA
and after reading the below link, you will have a better understanding of

Also included below is a link to the best essay that I have ever read, on
the relationship of energy and economics and why the USA is currently at
the brink of catastrophe.


Lowell Prag

---------------------------- Original Message ----------------------------
Subject: [SOLAR] Time to concentrate, by Jackie Jones
From:    "Lowell Prag" <lprag@mail.msen.com>
Date:    Sat, February 25, 2006 3:13 pm
To:      solar-concentrator@cichlid.com

Excellent overview on what's happening in concentrator pv,
in last months Renewable Energy World magazine:

Time to concentrate, by Jackie Jones


Home page of: Renewable Energy World magazine

I get it free by regular mail each month, through one of their media
outlets but I can't remember which one. If you search around, you can
probably find one of them.

Excellent info on all areas of renewables. Their online version doesn't
give the entire contents for that current month but it is online the
following month.

This essay on the relationship of energy and economics,
in this months issue, is also well worth reading:

The end of an ideology:
has capitalism as we know it run out of answers?
By Jonathan Porritt


Home page for all their free magazines:


Lowell Prag

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