The grid sizing videos were very informative.
I like that your videos are very current - you mentioned Solar City leaving NV when the net-metering agreement was changed. The Chinese company ENN (Reid's son is involved) bailed on their $5B dollar solar plant back in 2013 because they couldn't sell the energy generated from their solar plant to utilities in Nevada. If ENN return's now, it would provide some credence that the net-metering change was political.
There is a slight difference in the annual average between the NREL and NASA websites for a given GPS location. What would be the cause?
The Optimum Angle on the NASA site would make using the Wattsun Seasonal Adjustable Rack easy to set. Per the Wattsun website, the east-west axis would have a solar yield gain of 20%
For another course I have used rooforders.com to get a detailed presentation of a roof ($20-$25). I was able to import the dxf file into Sketchup. You weren't joking that there is a learning curve with Sketchup!!!!!
I heard some talk on a GTM Podcast about some kind of Senator Reid, Cliven Bundy, China/BLM/Tortoise/Solar/Cattle conspiracy and meant to look it up.
It sounds like you already know what is going on and here is what I figure is a fact based source (Politifact):
I found another source that was obviously political that had communist China photos of Reid merged with solar modules, proving that solar is a communist plot to take over America. Hahaha. I am glad those people keep me entertained. I like a good conspiracy theory, and probably some of them are true.
To get to your question about data from NREL and NASA, NREL gets a lot of its data from land and NASA extrapolates from space. Whatever data you use, it is going to be off somewhat, so best is to compare data to real results on a completed job and them use those figures to further detail your figures. Remember, we are working with a lot of inexact variables, weather, atmosphere, temperature, dust, pollen, bird droppings, shadows, morning dew, clouds, wind, degradation, resistance, etc., so the best we can do is a good guess and the more experienced we are, the better we are at guessing. NREL is really experienced with solar, so I would pick NREL data first, but NREL data is not everywhere, but NASA has data for all of Earth and even Mars. I am trying to model Oman right now and it is not as easy as NREL country.
I like that RoofOrders.com report! I just downloaded the sample solar report and might just have to use them sometimes. I just signed up to do financing through a company I have been teaching for for years and they have their own way of doing reports that I am learning with a range finder. Amazing how fast the industry has adapted after the Solmetric Suneye was taken off the market.
I can tell you are a good study!