@jerry33 is in Texas. Energy is outrageously cheap there. In some cases, it's free.$1800 in electricity for 78,000 miles???
78000 * .31 = 24,180 kwh. 1800/24180 = 7.4 cents per kWh. Is that all you pay?
The ROI on my solar array when I lived in Austin was 18 years. This, despite the 30% federal tax credit and an aggressive utility credit ($3.75/watt at the time). Mostly that was due to the very low cost of energy.
PG&E makes the PV investment a much clearer financial decision.