When one requires an electricity supply outside a township i.e. for a bush block in a rural location (at least in SA), one must pay the full cost of provision of the electricity supply.
I my case, even though high voltage power lines crossed my property, I would have had to pay for an extension of the high voltage line and a step down transformer. This cost was estimated to be about $30,000.
Several of my neighbours are off-grid because their build sites were remote from suitable power lines.
Their quotes were in the range of $70,000 to $100,000. An extension to a high voltage power line could cost $100,000 per km. This may be complicated by the need to get easements across other peoples properties.
Some people may not like overhead power lines as it spoils their view. Undergrounding high voltage power lines could cost double or more.
To go off grid means making changes to your lifestyle in so far as reducing peak electrical power demand. I.E. having a solar passive house, no or little air-conditioning nor electric heating and not having an all electric kitchen. Using a clothes line instead of electric dryer etc.
Going off grid is probably best dealt with in the Eco forum.
We were in that exact situation, quoted $45k for electricity supply so went off grid for $35k, although we have been very careful with what we are putting in the house eg. Wood heater & gas oven we have found that we can use far more electricity than expected which is great.