Letter Re: Handy Photovolatic Calculators

I’m a retired U.S. Navy Chief Petty Officer who has taken restoration carpentry as my second career.  I’ve been following you for a couple years now and very much appreciate what you’re doing. To those ends, I received a link to this article from Fine Homebuilding and thought it might be interesting and perhaps useful to fellow preppers.  Of particular interest to me was the interactive maps from NREL.  One can point their mouse to a particular point on the U.S. map (or to pre-selected points on the global map) and then load the location data into NREL’s PVWatts Calculator.  The calculator then shows the user location-specific data regarding positioning of arrays, available sunlight by month for the location selected, DC to AC inversion de-rates, et cetera.  

It occurs to me that calculating the value of the energy produced by a notional PV array would be useful so long as we remain grid-up as it provides the user the ability to calculate an amortization schedule for the investment.  Going the other way, as I’m currently noodling, it provides the ability to develop an electrical load scheme for a home factoring location, budget, and power requirements.  For example, wiring a completely separate DC bus not tied to the grid with a lead-acid battery backup versus using the standard residential AC bus with DC-AC inverter and grid-tied.  Or, a dozen other permutations to arrive at the best bang for the buck.  

Cheers, – Joe B.