Assuming my townhouse has a roof that is optimal to get full coverage from an optimally angled 100% efficient photovoltaic cell that is 16 square meters in size, on a clear day my solar array would produce on December 21st a bit over 10.6 kWh on average. So 254.4 kW per day on the worst day of the year.
The Tesla S uses 85 kW/h. I could drive 3 hours a day, assuming no household use and perfect transference/storage.
Or more realistically, 1 hour a day, and that leaves 269.4 kW for household use. Since the average household in the US of 1500 sq.ft. uses 864 kWh per month, I'd have an excess part way through the third day to "sell" to others.
So even at 50% efficiency, I'd have plenty of power, assuming clear skies, and the worst day of the year to gather every day.