tracking off-grid [RE-wrenches]

[Allan Sindelar]

William,
I am responding to your comment about tracking off-grid, as we seldom track
off-grid. My logic is that tracking adds about 40% to daily output in the
summer but only 15% or so in the winter. As trackers are considerably more
expensive than fixed (usually pole-top) racks, we usually elect to spend the
marginal cost of a tracker on more array. This is because the same $$$ spent
on PV buys a greater increase in average daily winter output, when it's most
needed. There are exceptions and special cases, such as larger off-grid
systems with relatively modest arrays, where the tracker meets all needs
part of the year and propane in the gennie covers more during winter.

We will track grid-tie if the customer's property allows it, they want it
and like the visibility, etc., because all power produced is credited, so
summer excess generation is used to benefit. But a tracker seems to provide
the most off-grid benefit when it's least needed. I'm interested in your
thoughts on this.

Allan at Positive Energy

-----Original Message-----
From: William Miller [mailto:wrmiller at charter.net] 
Sent: Friday, April 11, 2008 11:41 PM

Ray:
Sorry, didn't mean to offend.  Yes, the scenario is for grid-tie.  For 
off-grid, we like to track, if we can.


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------