We had the largest array of panels that were legal along with 4 Tesla battery banks installed in our home. This system cost approximately 60k before tax incentives. In the summer we make %200+ the amount of electricity needed. These end up being tax credits later when you don't make enough. In December, January, February and even March there are days where we are only making %10 of what is needed. Having a tank in the ground that feeds a generator is the only way that we found that makes it capable of being completely off grid if we wished. To answer your question with everything available now, there isn't a viable option to be completely self sustaining and live a modern electric hungry life.