PVWatts Sun-tracking derate factor value

The PVWatts v1 by default uses value 1.0. On help pages there stands that for value of 1.0 PVWatts calculator assumes that the PV arrays of tracking systems are always positioned at their optimum orientation and performance is not adversely affected.

But what about "Fixed Titl" array type systems? Should Sun-tracking derate factor be set to its lower value (0.95, the range is 0.95-1.0) when one uses "Fixed Titl" array type systems (as the losses due to orientation are the larges at Fixed Tilt systems, in comparison with 1 and 2 Axis Tracking ones)?

Thank you for the reply.

Hello,
In SAM 2014.1.14 and earlier versions, the PVWatts model uses a single derate factor to account for various losses in the system. The documentation for the online version of PVWatts V1 describes loss factors that you can use to estimate the derate factor for your system by multiplying them together. One of those loss factors is called "sun tracking." Here's the description from the PVWatts V1 documentation:

The derate factor for sun-tracking accounts for losses for one- and two-axis tracking systems when the tracking mechanisms do not keep the PV arrays at the optimum orientation with respect to the sun's position. For the default value of 1.00, PVWATTS assumes that the PV arrays of tracking systems are always positioned at their optimum orientation and performance is not adversely affected.

Based on that description, for the fixed tilt option, the sun-tracking factor should be one.
The current version of PVWatts  and the newer versions of SAM (currently in Beta test) use a different convention for the loss inputs, so my description here is about the old versions.
Best regards,
Paul.

Thank you for the reply Paul.