Thanks to high electricity prices and low gas prices it now costs less
per mile to run our Prius Plug-In on gasoline than on electricity.

Miles per Gallon: 45
Price per Gallon: $3.00
Cost Per Gasoline Mile: 6.67¢

Miles per KWH: 4
Price per KWH: $0.324 (no joke!)
Cost Per Electric Mile: 8.10¢

A Tesla is about 0.5 KWH/mile so at the same electricity cost it's far
more expensive than a gasoline powered vehicle.

The problem is the high electricity cost in my area. In areas of the
country where the electricity cost is half the price then it'd be
break-even for the Tesla, and a savings on the Prius. We are not big
electricity users since A/C is rarely needed here, and the water heater,
furnace, and clothes dryer are natural gas. But we always end up in the
top tier for electricity usage ($0.32445/KWH) which starts at 201% over
baseline.

The tremendous advantage of a plug-in hybrid, or all-electric, in
California, is the carpool lane access with a single person. And due to
state and federal tax credits, and factory to buyer incentives, the
Prius Plug-In was the same price as the gasoline-only model, and Plug-In
came with navigation and several other features. The carpool lane access
is really nice even though I don't really agree with the idea that
single occupancy vehicles should ever get to use the carpool lane; OTOH,
every additional vehicle in the carpool lane means less vehicles in the
other lanes so there is some benefit to everyone.