Since modules are getting so inexpensive, the big questions is what is
the best way to get 33% more power? Is it better to use 33% more modules
on a fixed array, or use a tracker? Which one costs less? It costs
$1.50 to $2.00 per watt for a tracker. If modules cost $3 per watt and
a fixed mount costs $.040 per watt , 33% of $3.40 per watt is $1.12 per
watt. And trackers don't come with a 25 year power output warranty. I
see tackers making sense when the array is powering a centrifugal pump
in the summer or possible a time-of-use grid tie that pays more in the
summer. You are definitely better off with more modules on a fixed
array in an off grid situation because you always need more power in the
winter when the tracker is least effective.
David
David Katz
Chief Technical Officer
AEE Solar
1155 Redway Drive
P.O. Box 339
Redway, CA 95560
Tel (707) 825-1200
Fax (707) 825-1202
dk...@aeesolar.com <mailto:da...@aeesolar.com>
www.aeesolar.com <http://www.aeesolar.com/>
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Dana wrote:
You got it!
It boggles my mind to watch the two OB FM60s and see the difference
each day and then to go back and see the data over time. It is a very
good argument for tracking. We have a Durango client that we installed
12 KW GIT tracked and it is outperforming the expectations of our
client too.
Dana Orzel
Great Solar Works, Inc
www.solarwork.com
E - d...@solarwork.com
V - 970.626.5253
F - 970.626.4140
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I will be the shift in how the world uses power! - Dana Orzel
*From:* re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of
*Allan Sindelar
*Sent:* Thursday, December 31, 2009 8:13 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Evergreen
Dana,
Thank you for this information. I would like to clarify what you
wrote. We have long accepted that trackers may be expected to increase
daily output by about 35-40% in the summer and 10-15% in the winter,
due to the differences in the sun's seasonal elevation and the
resultant length of the solar day. It sounds as if you measured the
effective increase from approximately summer solstice - winter
solstice and got a 32% gain. You previously got the same gain (33%)
measuring from last winter solstice to summer solstice. This makes
sense, as it averages winter and summer gains over two roughly equal
periods, with variations (summer monsoons, etc.) being within
acceptable error.
And whether grid-tied, grid-tied with backup, or off-grid is
irrelevant as long as you can compare and record the outputs of the
two otherwise identical arrays, one tracked and one fixed.
Do I understand this right? If so, it's good real-world data for
design purposes.
Allan
*Allan** Sindelar*
al...@positiveenergysolar.com <mailto:al...@positiveenergysolar.com>
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
*Positive Energy, Inc.*
3201 Calle Marie
Santa Fe, New Mexico 87507
*505 424-1112*
www.positiveenergysolar.com <http://www.positiveenergysolar.com/>
Dana Orzel wrote:
This is for a grid tied with battery backup Outback system.
The 32% increased gain for the tracker VS. fixed mount production is
an average of the last 180 days and I checked it in the spring for the
last 180 days [over the winter] and it was 33%. The 12 -- Evergreen
180 watt modules produce about 65 -70% of our home and office's
electrical requirements.
Thanks,
Dana Orzel
Dana,
That 32% is a very useful number, and it matches with our
experience as well. But I need to verify a couple of assumptions,
please:
Does this represent average annual production, rather than peak
seasonal? And is it a grid-tied system?
Thanks,
Allan
Allan Sindelar
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