" wrote:

We can forget about generators and distributions systems.
Just take two 12V batteries and connect them in parallel

There's your problem right there.

It's usually not a good idea to connect batteries together in parallel,
unless they are exactly of the same type, age, condition, etc. If you
get a weak cell in one of the batteries it will turn into a load.

And what happens when they are not exactly at the same voltage before
being connected together? How do you insure that you always get current
flowing out of both of them?

But clearly he thinks if we put a second AC power source on
a distributions system, it has to be at a higher voltage to
"push" current out.

The IEEE paper I posted earlier today shows exactly that - that PV
systems raise local grid voltage and the utility company must compensate
by reducing primary supply voltage to down-regulate the secondary
voltage coming from the distribution transformer.

So, what happens with the two batteries? Under the
laws of physics the rest of us use the voltage would
remain at 12 volts and BOTH batteries would be supplying
part of the 1 AMP flowing through the resistors.

Take a 12 V car battery and wire it up in parallel with 8 AAA batteries
connected in series. Then connect a load and tell me how much current
the AAA batteries will supply vs their what their potential current
supply could be if they were connected to their own isolated load.

Not on Homeguy's and Vaughn's planet. One of the batteries
will be charging the other.

If they are unequal in capacity, then yes that will eventually happen.