Passat TDI vs Chevrolet Volt

During a conversation, an interesting comparison between a Volkswagen Passat diesel and a Chevy Volt hybrid ensued. Here's why the Passat wins.

Spurred by commentary here on Torque News in comments left on an article by Keith Griffin (see it here), I had a conversation with a Volt owner in California about her car. At the time of this writing, I have a 2012 VW Passat TDI SE Premium in my driveway as a loaned test vehicle from the manufacturer. Together, we compared notes and furthered the conversation that started in Torque News comments.

The Passat TDI SE is similar to the Volt in fittings and extras, though it does have some things that are of higher quality than the Volt such as the premium Fender sound system and powered seating. Downgrading some of those options to equalize the cars in that regard puts the MSRP for the Passat TDI at about $29,000. MSRP for the Volt is about $42,000 in comparable trim. Doing a sticker-to-sticker comparison, the Passat is obviously cheaper, but after taking in the federal tax rebate of $7,500, the Volt's price tag gets closer at $35,000. Some states have further incentives for purchasing a car like the Volt, but for this comparison, we're assuming a national average which means no state-level rebates or incentives.

Assuming a road trip, the range per vehicle on the highway is 796 miles in the VW and 379 miles for the Volt. For daily driving, numbers are more variable, but most Volt owners claim around 900 miles per tank of gasoline while my use of the Passat and a survey of Volkswagen forums shows that most TDI drivers are getting 820 miles per tank of fuel. Diesel fuel and the premium grade gasoline required for the Volt cost about the same, but tank capacities are different. So in today's fuel costs (roughly $4/gallon for diesel or premium gasoline), including a national average of $0.12 per kWh for electricity, the $60 fill up on the Passat is compared to a $42 fill-up on the Volt. For reference, I'm assuming two recharges per week from empty (80%) on the Volt's batteries, which seems fair even if it is not being depleted completely, but is being plugged in nightly.

Finally, we look at the cars themselves in terms of practicality and everyday use. The Passat is a larger car physically, with seating for five (comfortably) inside (compared to the Volt's 4), more trunk volume, etc. In safety, both cars rank about the same in IIHS tests. The VW has better handling and performance, however, with a slightly faster 0-60mph rating and a higher top speed. Riding in either car shows the Passat to have a more comfortable drive.

Warranties are the same at 36k/3 years basic. Where the Chevy Volt wins out is efficiency. It's miles per gallon combined is over 90 while the Passat TDI gets 31mpg in the city and 43mpg on the highway.

A dollar-for-dollar comparison, however, gives the Passat TDI the edge. At $6,000 cheaper off the lot and with a fuel cost of $0.07/mile (versus the Volt's $0.05), the Passat is an obvious choice. This narrows after factoring in maintenance costs - oil changes are about the same price for both vehicles, but the VW requires after-treatment be added every 10,000 miles (two oil changes) at an additional cost of about $40. The Passat TDI, however, has no spark plugs. For the Volt, this would be about $8 per plug ($32), plus another $25 for wires, all being replaced every 100,000 miles. We're assuming here that costs are for parts/fluids only.

Using these numbers and assuming a 150,000 life span before trade-in or sale, we have a cost breakdown of: $0.03 per mile ($10,500 in fuel, $600 in after-treatment, minus $6,000 price difference) for the Passat TDI versus $0.05 per mile ($7,500 in fuel, $85 in maintenance) for the Volt.

These numbers have a big caveat: subjectivity. Those who live in the city and drive in congested urban traffic and/or heavy commuter traffic are more likely to see cost savings with the Volt than they are with a TDI. On the other hand, those who do not drive under those conditions regularly will likely find the Passat TDI a better choice for their needs. Finally, if you are one of the few who live in an area that further incentivizes the purchase of the Volt (and you can take advantage of those incentives), then the numbers will also change more towards the Volt's favor.

The numbers above, though generalized (the cost per mile is actually higher, since I did not include other vehicle service requirements, such as the cost of oil changes, tire replacement, etc.), they illustrate the cost difference in terms of operation for the two vehicles.

Update 5/23/2012: Information I did not have about the Volt not requiring oil changes per mileage (see commentary below) changes the metrics somewhat. This would raise the cost/mile of the Passat TDI by about a penny, putting the two closer together in terms of cost.

Update 5/25/2012: I have been informed by General Motors, after a VP I have spoken with previously read this article, that I will be receiving a Volt for a week long test (the same as my time with the Passat) next week. This will give me a chance to re-asses the Volt under the same conditions I tested the Passat TDI. I will write a follow up after that. My goal will be to re-asses the Volt based on the new, longer period of testing as up to this point, the longest I've spent driving one was less than an hour. This should make those of you whose only argument with my assessment here is that I "haven't driven one" happy.