Care to provide at least one link for one of these studies? I have read many. I am not in the habit of opening my mouth unless I have done enough research to confirm my hypothesis. I can still be wrong, yet, based on what I have seen in the domain, most of these studies have an element of "then a miracle occurs" in them. This can take the form of highly theoretical --when in real life things are never linear-- or a bunch of hand-wavy stuff that can't support the conclusions reached.

I made some adjustments to my models and was able to get the cost of solar with batteries down. However, to be fair, I now need to factor in the actual solar generation efficiency (meaning, panel rating vs. what you actually get at the peak) as well as to account for the fact that the actual output power curve is roughly an inverted parabola. The energy produced by the system, then, would be the integral of the power curve over the period of solar production (roughly 7:00 AM until 5:00 PM).

One must then take into account that system efficiency (DC to AC conversion, battery charging, battery discharging) must consider a range of variables. For example, the Tesla Powerwall 2 is rated at something like 90% efficiency while only drawing 3.3 kW at what I would all laboratory-type environmental conditions: 25 degrees C. I am having trouble finding data on actual efficiency under real environmental conditions, hot and cold.

Beyond that, the efficiency of the cells (for any battery, not just Tesla's) degrades over time. In Tesla's case, they guarantee 70% over 10 years.

This means also modeling the replacement of millions of battery packs per year at or around the ten year lifespan range. Losing 30% of energy production would be a problem. So, you either overbuild or replace everything as soon as it drops below a certain threshold.

Over the 20 year deployment model I created, 5% of the battery packs would have to be replaced every year starting somewhere around 7 to 10 years after installation.

Then there's the lifespan and behavior of solar panels. I'll make the assumption that at the 20 year warranty expiration point, most solar panels will be at about 80% production. This assumes no other environmental factors are in play (dirt, scuffing of the glass, etc.). To finish the model one would have to include the negative temperature coefficient of panels: As the operating temperature increases, output decreases. A typical panel might have a coefficient of about -0.35% measured from a baseline of 25 degrees C. At 35 C, the panel produces 3.5% less energy. Panels can run very hot (60 C) because, well, the sun will heat them...they are not white reflectors. At 60 C the loss can be as high as 12%.

This, BTW, is why I installed three large (~6 ft diameter) fans under my solar array. I haven't done the math yet but I suspect they pay pay off in efficiency during the hottest periods of operation.

The model would have to allow for both failures and replacement due to degradation. I have friends with arrays consisting of around 15 panels who have already had to replace two or three panels after ten years. Once again, reality is far more stochastic than data sheet specifications.

Anyhow, the point is that the real-world model of solar energy systems is far from the simple idea of a solar array delivering power consistently and at peak performance.