With complete details of Toyota’s Prius Plug-in Hybrid being revealed, Pike Research has found that the Volt is slightly cheaper to drive than the Prius plug-in, as long as you are going less than 70 miles between charges. The calculations were based on gas prices set $3.50 and electricity at 11 cents per kilowatt-hour. At distances greater than 70 miles, however, the Prius PHEV was the more cost efficient option.
The Prius can go about 14 miles in pure electric mode before its gas tank kicks in, while the Volt has an electric range of about 35 miles (per the EPA). On the other hand, the Prius PHEV will get 49 MPG in hybrid mode, while the Volt gets 37 MPG. This difference eventually is what causes the price shift.
Of course, neither car is a gas guzzler and the question for customers eventually becomes whether they need more electric driving range, or total vehicle fuel efficiency, as Plug-in cars mentioned.
There are some other differences as well. The Prius PHEV will be able to drive in HOV lanes in California because of its low total emissions, while Volt owners will not. The Volt's large battery pack though, will allow its owners to get the full federal tax credit ($7,500), while Prius PHEV owners will only get $2,500.
It is important to note, though, that for distances less than 15 miles though, both cars will cost exactly the same to run, because you will be driving in electric-only mode.