No problem with a different circuit, but more so if you want to
connect to the supply. In fact people with wind etc. generators can
get permission to sell "green" electricity back to the grid
(automatic metering). It would be somehow satisfying buying night
time electricity from the suppliers and sell it back to them at a
profit.

How is that arranged? I presume the windmills produce DC?

Or if AC how do they arrange synchronisation with the
mains?
===============================
Domestic wind energy systems in the 1-10 kW range often involve an AC
generator ,its output being rectified with the DC fed into an inverter
which is synchronised with the grid.

In the UK a company 'Windsave' sells and (obligatory) installs 1 kW wind
generators which are connected to the domestic 230V-50 Hz system .
The location of the windgen and its nearby inverter cannot be too far
away from the switchboard (up to 15 metres). Apparently the output
voltage of the inverter is slightly higher than the grid supply , such
there is a preferential pick-off from the wind gen system.
However when no power is consumed wind generated energy is fed into the
grid.
I have 'heard' that in some countries (but not in the UK)
electro-mechanical kiloWattHour meters can rotate reversed when fed
with power from the consumer's side, with the counter counting down .
This would be very beneficial for people with the above described system
.. Perhaps someone on this NG can confirm that these meters really exist
and in which countries.

For my AR operations + desk lighting and peripherals I use 12 V
batteries charged by an up to 170 Watts windgen and 2 solar panels with
a total capacity of 128 Watts(peak)............just for the h*ll of it.
The wind gen. has a 3 phase generator and integral rectifying diodes( in
fact 2 bridge rectifiers of which 1 is fully utilised and the other one
only half )

Frank GM0CSZ / KN6WH The future is 'renewable'