[Carry_Okie]

Your excellent analysis charitably presumes neither the cost of batteries, inverters, etc. nor the fact that the solar cells themselves have an expected life equal roughly to their payback period; i.e., once they have "paid for themselves" you have to junk them and buy replacement cells. It also neglects the cost of disposal and/or recycling as well.

[Boot Hill]

• "Your excellent analysis charitably presumes neither the cost of batteries, inverters, etc."

Correct! Nor did I include the single biggest additional cost, the interest on the capital investment. When the additional costs of installation, mechanical supports, power inverter, wiring, building permits and interest are figured in, that payback period will be on the order of three times as long, or about a century.

Batteries are unnecessary for the grid tie system that the vast majority of solar power installations use. But if you want to calculate the cost of a stand-alone, non-grid tie system, you can start by reducing the energy efficiency by an additional 1/2 to 2/3 and increasing the cost by an additional factor of 3x.

In regards to your comments about solar array life time and failure mode, most people are unaware that the multitude of cells that comprise a single solar module (typically 50-100) are wired in series, just like the old fashioned Christmas tree lights, thus if one goes out, the entire sealed module is useless.

Question:   Since you can't turn a solar panel off, if a ground level installation ever became flooded, would you electrocute yourself first or would the explosion from the electrolytic production of hydrogen and oxygen kill you first?

--Boot Hill