It's my understanding that these
gridtie systems sample the grid's AC line and generates AC voltage that exactly matches the frequency, phase and voltage amplitude. (Maybe a tad higher on the voltage).?.
This newly generated PV power is converted into an almost exact clone of
what's in the grid on your street. So, the new juice can be mixed right
into the grid (and used by your next door neighbor) without making a ripple.
BUT, If you have a regular old LCD type electric meter, and you connected a "gridtie system" to your power mains, what would happen?
Your meter explodes? Or, it runs backwards?
Or perhaps the meter slows down? as you use your own local PV power??