My friend Eric is considering the purchase of a plug-n Prius. And on a thread on his forum, riceme asked about what it costs to drive one.
I ran the numbers and posted this...
To calculate the cost of driving on electric, you need to know two things. The vehicles energy consumption rate, and the cost per kWh of electricity where you're located.
The Prius PHEV consumes 32.2 kWh per 100 miles.
And the Gulf Power rate is about 10 cents per kWh (although they just announced an upcoming increase).
To get the cost of driving 100 miles on electric, you multiply one by the other. And that tells
you it costs $3.22 per hundred miles or 3.2 cents per mile.
To compare that to the cost of driving on gasoline, the Prius PHEV gets about 50 mpg in gas mode.
With gas at $3.40 per gallon, it will cost $6.80 to go 100 miles or 6.8 cents per mile.
So with the current cost of gas and grid electricity in our area, it costs about twice as much per mile when driving on gas than when driving on electric.
The electric range of the Prius PHEV is 11 miles. But that's with the A/C switched off. By googling, I just discovered that, on average, an electric vehicle will lose about 16% of it's range with the A/C switched on. So that 11 miles then becomes closer to 9 miles. But since we don't use the A/C year round, we can probably estimate the year round range to be about 10 miles.
So it all comes down to the particular motorist's driving routine. What portion of driving will you be doing in electric mode?
I am probably the best candidate for buying this car. Why? Because most of my daily trips are all under 10 miles round trip. And if I spring for a 240 volt charger, which will charge the car in 1.5 hours (compared to 3-4 hrs at 115 volts), then I will be able to recharge at home between several driving trips per day.
I drive about 10,000 miles per year. If 5000 of those miles are driving on electric, then it will cost me $160. And the 5000 mile I'm driving on gas, will cost me $340.
For a total annual energy cost of $500.
The same annual cost of driving a conventional Prius (getting 50 mpg) would be $680.
So, even though my driving routine is ideal for owning this car, even I would only save $180 per year compared to driving a conventional Prius. A driver with a typical driving routine would save less, and many would save a lot less.
And I would have to pay about $5000 more for the PHEV version of the car than for the conventional version. It would take me 31 years to recoup that difference in initial purchase price.
Of course that's assuming the gas continues to cost $3.40/gal. If the price of gas increases then I would see a little more savings. But it's still far from being a cost-effective choice.
But money is not the ONLY consideration for owning this car. Some (including me) have a weird obsession with wanting to drive a car on electricity. I like the idea of giving less money to the oil companies and Saudis (especially since I own electric utility stock LOL). And then there is the geek factor (which also includes me) which is the fun of owning the cutting edge of driving technology.
But there is one last thing to consider. The traction battery in the PHEV version is a lot more expensive to replace than the battery in the conventional Prius. So if you're planning to drive the car enough miles to need a battery replacement, that battery replacement is going to cost you a lot more.