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• The red lines in this image show the actual energy generated during a cloudless day in late summer. The area under this curve corresponds to 17.2 kWh.
• The dashed yellow lines (from left to right) indicate 9am (when the shadow of the dormer left the panels on the west side), 1pm (when the sun was due south), and 4:30pm (when the tree's shadow reached the roof).
• The black curve represents my theoretical estimate of the energy that could have been generated under ideal, unshaded conditions. The area under this curve corresponds to 20.2 kWh.

The area to the left of the 9am line corresponds to 0.7 kWh, which is the amount of additional energy that would have been generated if the morning sun wasn't partially blocked by the dormer. The area under the peak of the black curve corresponds to 1.2 kWh, which is the amount of additional energy that would have been generated if the inverter wasn't limiting the power (a problem that was apparently corrected in November). The area to the right of the 4:30pm line corresponds to 1.2 kWh, which is the amount of additional energy that would have been generated if the afternoon sun wasn't partially blocked by the dormer and maple tree. The shading effects will lessen when the sun rises and sets farther south.

Summary:

Condition	Energy	Percent of Theoretical
Theoretical	20.2 kWh	100%
Actual	17.2 kWh	84.8%
Dormer Shading (morn + eve)	1.3 kWh	6.5%
Maple Tree Shading	0.5 kWh	2.6%
Flat-top Effect	1.2 kWh	6.0%