For this research, I called several solar companies. However, the only three that would provide quotes over the phone were Tesla (formerly Solar City), SunRun, and Elevation Solar. All three were more than $.11/kWh. This is still $.03/kWh more than what I'm currently paying on average. Here's the monthly data from my house. On average, my actual cost for the last 12 months was $.09/kWh which is not far off from the $.086/kWh in my electricity provider contract.
According to PowerToChoose.org, It looks like the price for my usage is dropping to $.076/kWh for the next 12 months.
The good news is that the average solar power price since 2015 has dropped from $.13/kWh to $.11/kWh. If the rate reduction of $.01/kWh per 2 years continues the projected breakeven rate of $.09/kWh would arrive in 2023. It is worth noting that my electricity rate has been under $.10/kWh for more than the last 15 years where I live in DFW.
Unfortunately, my prognostication regarding lowering the cost of solar by 10x with the transition to graphene-based solar cells has yet to be realized. I'm still hopeful as the scientific community still believes that graphene will dramatically increase the energy capture percentage and improve energy transfer efficiency. As a bonus, graphene's transparency lends itself to a much larger array of applications including windshields, car wraps, phone screens, home and business window films, ... etc.
The following video provides a great primer on the rationale for graphene efficiency improvements.
Other innovations in solid-state batteries and super-capacitor storage will also greatly improve energy transfer efficiency and reduce the cost of electricity storage over the next 5 to 10 years as well.
Once these three technologies are fully realized and applied solar power solutions, the price for electricity will likely drop to less than a penny per kWh. Hopefully, we will see that power revolution in my lifetime.
Two very important notes regarding investing in a solar system in Texas:
1. The technology employed at the time of installation cannot be upgraded until you pay off the loan. Therefore, if solar efficiencies double next year, you can't take advantage of that benefit for 20 years or until you pay off the loan.
2. If your roof gets damaged by hail, the installer has to remove the solar system and then re-install it after the roof is replaced. The costs for removal and re-install depends on the number of panels installed. One company's estimate was $7,000.
Let's consider an example. Using current technology, the Tesla solution using standard tiles (not the cool roof tiles) including Power Walls would take 35 years to break even on a 20-year loan. Once the loan was paid, I would still have to pay for electricity because my house is not big enough for enough panels to exceed electricity usage.
If the solar capture and efficiency improve by 5x next year, it would only take 5.5 years to pay back the loan and then I would be accruing over $9,000/year of net-metered credit through excess load generation.
As for our house, we will wait until technology advances to the point that the break-even is less than 5 years.