Solar Panels Not on Appraisal

[Nick Michaels]

So let me preface this with saying that it is about my primary residence, which we don't plan on moving out of in the next 15-20 years, and view more of a place to live than an investment. 

When we initially did the mortgage for our house, we put down 5% because...  reasons I don't quite remember. Anyways, since purchasing 2 years ago we added a 2 BR addition and a 6.3 kW solar panel system on the roof. 

We were looking to get rid of our PMI and the lender gave us the option of ordering an appraisal ($500) or a BPO ($200). We went with the BPO and the guy came out and did it and it came back with it resulting in us being at 80.2% LTV, just .2% shy of what we needed, which left me a little skeptical, but what are you gonna do? We aren't planning on selling, so the BPO was strictly for the PMI removal, and a check for a few hundred of principal took us down to where we needed to be.

Now I'm not naive enough to think that "Well I bought at X, and added Y, so it should be Z" , we did what we did to the home to make it work for us. However, when I read the BPO I was surprised to find no mention of the solar panels at all. And the broker must have seen them, he looked at the electrical box as well and the inverter was right there.

Are solar panels viewed negatively in appraising a house? Or is the technology just too new that some just don't know how to value it?