GerryAZ wrote: I have a demand controller that sheds the ... ...
That is *outstanding*
Is that your own concoction ? Does it just shut down a sub-panel or are you controlling each load ?
I've thought for a long time that the key to solving demand charges was to improve the home envelope so that time shifting consumption worked but somehow you have done it, and in hot, hot AZ to boot. It sounds like PV will let you shave another couple kW off your demand charges while being less strict in your power rationing. I'll guess that someone in your home thinks that alone is worth the price of admission.
It is no wonder the PV salesperson was flummoxed. I'm surprised you even tried. Dump 12 months of consumption and demand charge data into a spreadsheet and compare to anticipated generation by the hour with PV.
Are you allowed to keep your plan with the PV addition ? I glanced at the APS rate schedules and thought I read that APS credits you about 12.5 cents a kWh for unused generation the first year, likely reduced by 10% yearly and done after 10 years.
Perhaps you can arbitrage APS
Quick math (and a peek at an example bill on your schedule) says you save 5.6 cents on a kWh self generated and self consumed during off-peak, 28 cents a kWh self-generated and consumed on-peak, and 12.5 cents a kWh self-generated and sent to the grid, and you reduce demand charges to one kW. You will pay about 10 cents a kWh for 10 years until the system is paid off (excluding financing.) Cash flow neutral or positive from day #1 and paid off in 10 years. In your shoes I would over-build my consumption as much as APS allows.
The deal is that good.