[stevehull]

Memphis,

You are correct in terms of understanding power balance. If you are using 6000 watts (5 kW) and the PV panels are putting out 1 kW, then you are only billed for the difference (5 kW).

Here is where you need to do some homework. Explore your utility bills and plot your monthly kWhrs used in each month. Your electricity use will likely be lower in the winter (in your location in the south) as you are not using AC at that time.

Then build a PV system that is just under the maximum you need for any month in the summer. You need to use PVwatts to do this as it will calculate your historical sunshine hours for your specific location. Not every day is 100% sunny . . .

In this way, you don't use the grid for anything, but you do use the 240 and 120 V wiring in your home.

I suspect that a 6 kW array (24 250 watt panels) would put a huge dent in your bill. The great thing about being in the south is the summer, when AC use is high, is also when the PV panels put out the most power.

Does this make sense?

Steve