The Volt uses ELECTRIC drive 100% of the time, so I urge you to embrace the measure of electrical energy over time, kilowatt hours (kWh), and the minimal effort to convert the gallons of gasoline energy of hybrids to kWh (36.4 kWh for each gallon of gasoline per the US DOE Kids page once you do megajoules of energy to kWh) and mix it in for the total vehicle cycle average energy efficiency .

It’s the total vehicle cycle average energy efficiency we care about as consumers and the ability to DIRECTLY compare that between any types of vehicles, full gas, any type of parallel, series or multi-mode hybrid or all electric. kWh / 100 miles (both battery only PLUS the gas supported portions of total vehicle range) allows us to do that, gallons of gas doesn’t.

Having said that, I do find your rankings based on least gas used per vehicle for same miles not a bad way to get the old schoolers to take a baby step towards the consideration of full vehicle efficiency and it certainly plays to the “get off of imported oil, keep our oil (and other) $ in the country and national security” folks. You take the first step, I make the transition and Van has the end game (all electric, no gas) covered, I think.

One last time, if it’s not average kWh / 100 miles for the entire vehicle range that you are reporting, your vehicle cycle energy efficiency analysis is incomplete. Also, only include the vehicle. Everything going to the battery and gas tank upstream from outside the vehicle is a completely different and complex topic. One major improvement in our analyses at a time.

1. Using gas as a metric is backward looking and prevents direct comparison of vehicle efficiency for full vehicle cycle between all types of vehicles. Using kWh / 100 miles allows for weighted averages in all types of hybrids, removes that deficiency and is the accepted not new vehicle efficiency metric for US DOE/EPA. As we move into electric drive, we can use the accepted measure for electricity, kilowatt hours (kWh) to be forward looking. Please hold your nose for just one post and jump in with me. The water’s not as bad as you might fear.

2. Your statement is factually incorrect. Neither kWh (kilowatt hours) nor miles are measures of money. Vehicle energy efficiency (full vehicle cycle in this case) in kWh / 100 miles has absolutely nothing to do with “how much you will pay … using electricity from your home”. It’s not hard to figure out, though.

According to Van’s numbers, the answer is 73.2 kWh / 100 miles for the remainder of the Volt’s range, where it uses gas to run the generator to recharge to battery.

Recall that the lower the number of kWh / 100 miles, the more efficient the vehicle.

You have to do a weighted addition of the gas based portion of the range to the more efficient battery only first 40 miles to see the vehicle’s full cycle average efficiency. I’ve done that for you below.

The estimate is 67.5 kWh / 100 miles for the Volt for an entire vehicle cycle and 25 kWh / 100 miles if you drive a Volt less than 40 miles, based on Van’s numbers. It’s the full vehicle cycle estimate that allows us to do direct vehicle efficiency comparisons for any vehicle types.

Details:

From a prior post on another thread:
“Van “expect[s] the actual performance to range from 3.5 to 4 miles per KWh for the Volt.” (post #162). That’s 28.5174 to 25 kWh / 100 miles for the first 40 miles (11.76% of total vehicle cycle range) . Then Van says that the “Volt is claimed to get about 50 MPG when operating in the charge sustaining mode.” Based on the US DOE conversion (again, I’ll use 36.6 kWh per gallon to be generous to Van and GM), that 36.6 kWh per 50 miles or 73.2 kWh per 100 miles for the remaining 300 miles (88.24%)of vehicle cycle range.

So, we now have a range for total vehicle cycle efficiency, from 28.5174*11.76% + 73.2*88.24% kWh / 100 miles, to 25*11.76% + 73.2*88.24%, which is 3.3536+64.5917 kWh/ 100 miles to 2.94+64.5917 / 100 miles, or 67.9 to 67.5 kWh / 100 miles. Let’s give Van and GM the benefit of the doubt and call it 67.5 kWh / 100 miles, the more efficient result, for the Volt for an entire vehicle cycle and 25 kWh / 100 miles if you drive a Volt less than 40 miles. This allows us to do direct vehicle efficiency comparison for any vehicle types.

For estimated comparisons of full vehicle cycle vehicle efficiency, from a prior post on another thread:

“2008 Camry Hybrid, Jetta TDI, Ford Escape Hybrid: 107.1 kWh / 100 miles

2009 Ford Fusion Hybrid mixed mode (ful vehicle cycle): 94.6 kWh /100 miles

Curent Prius mixed mode (full vehicle cycle): 79.1 kWh / 100 miles.
This mean that the Volt will be 15% more efficient than the current Prius when directly compared with everything fill on both cars going to everything depleted on both cars (gas tank empty and battery needing recharging). Good job, GM!

Current Prius with an aftermarket plug in power pack; According to Consumer Reports testing, 56 kWh / 100 miles. Hmmm.

2010 Prius Specs: 72.8 kWh / 100 miles. This mean that the Volt will be 7% more efficient than the next generation Prius when directly compared with everything fill on both cars going to everything depleted on both cars (gas tank empty and battery needing recharging). Good job, GM!”

This is the type of analysis we all better get more comfortable with, as it allows for direct comparison of full vehicle cycle (everything full to everything needing to be refilled and recharged) vehicle efficiency between very different types of vehicles (all gas, all types of hybrids and pure electrics), uses units are measure appropriate to electric drive (kilowatt hours (kWh) and miles) for when it is the dominant drive.

If anyone can improve on my work, with results reported in # kWh / 100 miles, please take a whack at it here. I don’t claim superior knowledge or perfection and these results are based on Van’s report of GM claims, a guess of 340 mile range with the first 40 battery only for the Volt, US DOE conversion of gasoline energy to kWh.

So far, it seems that all my work here is very much not appreciated, but without an accurate mirror, how can we see how we really look?

Thank you for the opportunity to respond to your post, Dave G. I respect the work you do on this site.

While I’m sure you could calculate the kWh (energy in gas) / 100 miles, I consider this an academic exercises, since gas efficiency is measured in miles per gallon.

For me, the most important measurement is gallons per year. I realize electricity isn’t free, but using electricity doesn’t support Iran’s nuclear bomb program.