The Cayenne seems to need about 315Wh / mile. I assume a substantial number of them are sold in California, where rates are often above $0.50/kw. I think $1.50 would get you about 9 miles.
I drive a more efficient PHEV and spend much more than $1.50/day.
I drive a more efficient PHEV and spend much more than $1.50/day.