Prius Plug-in Versus Volt: Which Costs Less to Drive?

Why do you still show the Volt using $0.20 of electricity for the first 5 miles but the PiP only using $0.13?

If the chart shows the PiP has 10 miles (9.75) of range for a 3.6 kWh charge and the Volt has 35 miles of range for a 12.9 kWh charge then both cars should have the same battery charge operating cost (around 2.7 miles per kWh).

 

You're not far off, mostly just the problem with your first two data point for the PiP, which you underestimate by about half. I figured 68 cents for the first 15 miles in the Pip (3 kwh at 33 cents and 0.1 gallons at 35 cents) or 4.5 cents per mile.

The Volt beats is at about 3.7 cents per mile (12 kwh over 35 miles at 11 cents per kwh).

 

Good work, I agree with your conclusions and your graphs as updated (until we get EPA numbers for the PiP).

Important to note that this is a dollar to dollar comparison where there is no difference between 1 gallon of gas at $3.50 or about 32 kwh of electricity.

I personally am not as concerned with low cost per mile as I am in using less petroleum. Even at equal cost, the Volt will use less oil until trip distances over 100 miles.

I am at 10,450 miles traveled and just over 82 gallons of liquid fuel consumed. For the same distance in a conventional prius at 50 mpg I would have consumed 209 gallons of liquid fuel. I charge for free about half the time so I did save a bunch of money, but the important part to me is that 127 gallons of gas (more than 6.5 barrels of crude).

My understanding is that even with the PiP the Volt will still use less gas (about 80% of the PiP) for most drivers (regardless of electric costs).

 

I should have clarified a bit. Mine is a 2006 with a Hymotion conversion. It doesn't display the kwh used, I am calculating it with a Kill-A-Watt meter and miles driven on purely electric. This is about a 5 mile round trip at low speeds of 31 mph or less. Yes, 31 mph, or else the engine will start up.

 

I still think the PiP will come out ahead in the long run compared to the Volt.. I just wanted to be able to do my daily drive/errands without using gasoline. I can say personally that if I travel more than 70 miles taking the Volt is NOT an option as its fuel economy dips below what we can attain in our regular 11' Prius. So 50 miles for the PiP to break even seems about right to me. I hope the PiP is like the Volt in which the 15 mile estimate is a "low ball" figure.. GM says the Volt is only supposed to go 35, but 40 is easily attainable. Hopefully the PiP will get somwhere around 20 in EV mode.

Personally I think my kwh/mile usage is high. On the myvolt.com site it says I use 32kwh/100 mile. I really do not pay much attention to overall consumption on it though unless I am driving from one side of Jacksonville to the other, but compared to other people going 50+ miles per charge I am kind of on the low end of the spectrum. I am going to Lowes to pick up that kwh meter today so I can install it on the line and see exactly what the car is drawing after my daily drives to work and back.

 

Agree with gwmort, good numbers with less gas. Cost difference based on trip lengths aside, get at least a 1/3 of the population to either buy a Volt, leaf or PIP or any hybrids, these numbers would add up big.

 

For me I am really big into hydrogen vehicles.. Especially since you can convert any conventional vehicle to use it without having to build an entire new car (like the electrics). Unfortunately to me I think the infrastructure will never come, and they will villify the volatility of hydrogen so people won't want it. I am unsure what the emissions side comes out to be for a kwh of electricity vs gasoline equivelent. No such thing as free energy though, so we are kind of between a rock and a hard place as far as that goes. People charging with solar at least have made a good trade off as they truly have next to no emissions on EV.

 

Doesn't this assume you can get the same number of gallons of premium from a barrel of oil as regular unleaded?

 

I suppose so, I guess I'm off by 6% or so (87 to 93 octane). The exact numbers not really the point its the reduced net consumption.

My home PV system just got all the permits approved and we're scheduling the install. Once done I'll have no emissions for 70% of my driving. I think its a good trade off from the imported oil.

John asked above about how much gas I'd have saved with the PiP. I'd say more would be saved than in a conventional prius but less saved than the Volt. My commute is about 20 miles each way with 16 of it at 70 mph or above, even with a full charge at home and work I'd be burning gas everyday in a PiP, where I normally don't in a Volt.

 

Since premium gas does have slightly less energy content than regular, and non petroleum sourced additives, such as ethanol, might be use to increase the octane rating. It's a safe assumption. Burning premium in an engine that can take advantage of the octane rating will likely lead less total petroleum use over regular.

 

Which costs less in Carbon footprint I wonder?

 

3.6 kWh is taken from the prototype vehicle but it had 5.2 kWh battery. This leads me to believe that the 10-15 miles of the PiP will use less than 3.6 kWh.
We should wait to the full specs and EPA official numbers before jumping to conclusions.

 

The mercury output from coal burning is pretty horrendous so a big thumbs up for you plugin and EV owners who are running your own solar or using a better mix of energy.

 

I could be churlish and ask why you hadn't already installed PV.

I know that PV economics can be significantly improved by running an EV as it can increase the value of a larger array. Do you have a TOU tariff?

 

I don't think its called a tariff but we are going to a TOU plan with the smart meter going in as part of the system. It'll allow me to sell power to the grid at peak rates during the day (when the extra generation is most needed) and then charge on lower rates at night for a net gain.

 

I must admit, I am quite amazed that you can do that! Very cool!

 

Everything I've seen points to the PIP as being less expensive in the long run than the Volt. However, the PIP still looks like a Jetson's car and the Volt has a more traditional look. I prefer the traditional car look.

I'm also not pleased that the energy drive display is such a terrible screen with a lower resolution than the NAV display. At least on the 2nd generation Prius it was much crisper with the LCD display. And this is where the Volt really pulls ahead with its displays.