My underperforming Tesla Solar system (formerly SolarCity)

Solar Savings

Customer with Tesla (formerly SolarCity) since Jan 16, 2015
Job number JB-8024630-00
Solar
System size
Months of
Tesla Solar
Service
Months
BELOW
Telsa Solar
MINIMUM
Seasonal
Estimate
Tesla Solar
Lifetime of Service
MINIMUM
Estimate
Tesla Solar
Lifetime of Service
Actual
Production
Tesla Solar
Lifetime of Service
Guaranteed
Production
All-time
Production
against
Guarantee
6.615 kW DC582635813.61 kWh36509.72 kWh41112.833333333 kWh

Here is my system design, as designed by Tesla Solar (formerly SolarCity). The trees are relevant here as you see in the excerpt from ticket #375201 below the image.


ticket #375201 excerpt
FROM: SolarCity rep
Date: Feb 1, 2016 10:26AM

Yes! I just heard back from the technical support team. They have found that system is electrically and mechanically sound. So, given the weather and shading conditions in your area, the system is producing at optimal level. As to why it is underperforming, they told me that it is primarily because of the shade from trees to the west of mounting plane one and also to the southwest of the array. If these shading issues were removed, the system performance should increase.

Hmm, so trees that were there when the system was designed and installed are now causing it to underperform by over 21% and not even produce the bare minimum estimate for year? The final design specs of the solar system did change slightly from the design above, but nothing to affect the system.

FROM: SolarCity sales rep
Date: Jul 8, 2014 9:25PM

We are pleased to provide you with the attached designs for your solar system. Our engineering team has been hard at work custom designing your system based on your home’s architecture and electrical infrastructure. Please take a moment to review the placement of your modules and inverter below as well as the attached PDF for a more detailed analysis of your system.


There were some changes to your design that require your approval before we can move forward. The following changes have been made during the engineering design of your system:

Due to module inventory/an electrical stringing requirement there has been an increase of 0.27 kW to your system size, however there was no change in the cost or your production guarantee.

Here are cost and system production estimates. The biggest thing to note are the cost estimates. I should be paying $62 to SolarCity and $8 (approx) to Xcel, but since the system is underperforming so badly, I'm paying $62 to SolarCity and often an additional $70 to Xcel.