Power back

Just got the first quarter winter power bill - apart for a mysterious error of 600k - revised - we ended up with a "bill" of $174 - meaning we covered the cost for the whole house even in winter.
I'm pleased.
nice to be self sufficient.
Come summer and the NSW feed in tariff we will also be making a "profit".
For this last bill it woould have been $900.
Wonder what the tax implications of this are :-) ?