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<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">Thanks
so much, Gary, for your study of power line shading over photovoltaic.<SPAN
style="mso-spacerun: yes"> </SPAN><?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><A
href="http://www.builditsolar.com/Experimental/PVShading/PVShading.htm"><FONT
color=#800080>http://www.builditsolar.com/Experimental/PVShading/PVShading.htm</FONT></A><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">It
seems from your study that the thin shadows do not have a significant
impact.<SPAN style="mso-spacerun: yes"> </SPAN>Also, it seems you are
right that distance softens the shadow as shown on Nick Pyner’s
picture.<o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><A
href="http://homepages.ihug.com.au/~npyner/wireshad.JPG"><FONT
color=#800080>http://homepages.ihug.com.au/~npyner/wireshad.JPG</FONT></A><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">I
will see if other feedback supports your main theory.<SPAN
style="mso-spacerun: yes"> </SPAN>I am still a novice. Based on Gary’s
study, it seems the site looking thru the power line is the better
location.<SPAN style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">However,
I went back to proposed site and considered locating the collectors under the
power line so there are no shadows from power line.<SPAN
style="mso-spacerun: yes"> </SPAN>I am not sure if this would be allowed
in easement of power line.<SPAN style="mso-spacerun: yes"> </SPAN>I also
checked sun exposure 15’ from centerline on South side of power line to get out
of easement.<SPAN style="mso-spacerun: yes"> </SPAN>These changes bring me
closer to the solid objects shading the collectors in the mornings of November,
December, and January.<SPAN style="mso-spacerun: yes"> </SPAN>The
recommendation I read is to if possible have full sun between 9am – 3pm (6
hours).<SPAN style="mso-spacerun: yes"> </SPAN>Sunrise in October,
January, and February is delayed until 10:15am or 10:30am.<SPAN
style="mso-spacerun: yes"> </SPAN>The location south of power line gets
shadowed 1:30pm in December.<SPAN style="mso-spacerun: yes">
</SPAN>Therefore, during the low production part of the year, more power
production is lost.<SPAN style="mso-spacerun: yes"> </SPAN>However, by
February until October, the collectors are in full sunshine.<SPAN
style="mso-spacerun: yes"> </SPAN>Late fall and early December have low
daily insolation.<SPAN style="mso-spacerun: yes"> </SPAN>Since the months
that the collector is full sun have higher insolation, perhaps on an annual
basis, that shading would not be a significant reduction. Does any have a sense
of what percentage of reduction might be?</SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">I
do not know if any recall our discussion of intermittent heating of high mass
building about a year ago.<SPAN style="mso-spacerun: yes"> </SPAN>However,
this installation is being considered to produce the power to run electric heat
element in an un-insulated solid masonry Quaker meeting house. I have always
considered insulation and tightness to be more cost affective than
production.<SPAN style="mso-spacerun: yes"> </SPAN>However, I am
reconsidering that in this case.<SPAN style="mso-spacerun: yes"> </SPAN>If
photovoltaic’s can be continually producing power all year including the peak
late spring early summer months, we can lower the conventional electricity that
has to be produced to serve the grid.<SPAN style="mso-spacerun: yes">
</SPAN>Therefore, when we consume it inefficiently intermittently in the winter
months, we can achieve net zero in electric consumption.<SPAN
style="mso-spacerun: yes"> </SPAN><SPAN
style="mso-spacerun: yes"> </SPAN>The combination of continual steady
production with intermittent seasonal high consumption seems to balance
out.<SPAN style="mso-spacerun: yes"> </SPAN><SPAN
style="mso-spacerun: yes"> </SPAN><SPAN
style="mso-spacerun: yes"> </SPAN><SPAN
style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">Of
course the conflict to being efficient is servicing a building for only 4 or 5
hours of use a week.<SPAN style="mso-spacerun: yes">
</SPAN><o:p></o:p></SPAN></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN
style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">Eli
<o:p></o:p></SPAN></P></FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=gary@builditsolar.com href="mailto:gary@builditsolar.com">Gary
BIs</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=greenbuilding@lists.bioenergylists.org
href="mailto:greenbuilding@lists.bioenergylists.org">Green Building</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, April 12, 2011 1:49
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Greenbuilding] Electrical
line shading of solar PV modules</DIV>
<DIV><BR></DIV>Hi Eli, Keith, ...<BR>Finally got some descent sun and a little
time to do the further testing on the effect of power line shadows on PV array
output.<BR><BR>The new results are here:<BR><A class=moz-txt-link-freetext
href="http://www.builditsolar.com/Experimental/PVShading/PVShading.htm">http://www.builditsolar.com/Experimental/PVShading/PVShading.htm</A><BR><BR>It
looks to me like for real world wire shadows from wires 20+ ft away that the
effect might be small to none.<BR><BR>Would appreciate any comments on this,
or things that might be wrong in the test.<BR><BR>Gary<BR><BR><BR>On 12:59 PM,
gdreysa wrote:
<BLOCKQUOTE cite=mid:%3C4D9C6F4C.6010607@gmail.com%3E type="cite">Hi
Eli,<BR>I'd agree with Keith that some caution is in order here.<BR><BR>This
is a picture of my Enphase PV array with some modest shading:<BR><A
class=moz-txt-link-freetext
href="http://www.builditsolar.com/Projects/PV/EnphasePV/Shading.htm"
moz-do-not-send="true">http://www.builditsolar.com/Projects/PV/EnphasePV/Shading.htm</A><BR><BR>You
can see from the real time output plot that even the panel with just a line
across it is very much effected.<BR>The shadow is wider than a power line
would cast, and maybe the effect would diminish as the shadow gets narrower,
but I'd be careful.<BR><BR>If I think about it later today and the weather
cooperates, I'll set up narrower shadow and let you know how that comes
out.<BR><BR>The micro inverters are good in that a shadow across one module
only effects the output of that one module and not the whole string, but a
wire shadow that goes across several modules could still have a serious
effect.<BR><BR>Gary<BR><BR><BR>On 12:59 PM, Keith Winston wrote:
<BLOCKQUOTE
cite=mid:%3CBANLkTikWHTbcWvMu9ZoG2i53g00zenTYfQ@mail.gmail.com%3E
type="cite">I'm not quite sure what you mean by "smaller than the sun's
disc"... larger power lines can cast distinct shadows. If those align with
an axis of the modules, then they may shade an entire row of cells in a
module, overcoming the ability of the bypass diodes to "bypass" the shaded
cells (most modules are, I believe, still bypassed on a cell-by-cell
basis, and are wired in series along one of their axis). So I'll stand by
my earlier comment that a power line could very well create significant
shading. But I agree with the microinverter
suggestion.<BR><BR>Keith<BR><BR><BR>
<DIV class=gmail_quote>On Mon, Apr 4, 2011 at 11:22 AM, Gordon Howell --
Howell Mayhew Engineering <SPAN dir=ltr><<A
href="mailto:ghowell@hme.ca"
moz-do-not-send="true">ghowell@hme.ca</A>></SPAN> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0pt 0pt 0pt 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>Thanks for your question Eli:<BR><BR>It doesn't appear
that the electrical lines would be a significant issue. They are
likely smaller than the sun's disc.<BR><BR>If you use Enphase
module-inverters (one inverter for each PV module) then any shaded
module wouldn't affect the PV array's performance, because each PV
string is a PV module.<BR><BR>To clarify: the industry term that
is an internationally-recognised standard for PV modules is "module",
not collector, not panel. See attached file for pictoral
description.<BR></BLOCKQUOTE></DIV><BR></BLOCKQUOTE><BR></BLOCKQUOTE><BR>
<P>
<HR>
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