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Think the Volt is greener than the Prius? Think again.
GM recently announced fuel economy figures for the plug-in hybrid Chevy Volt: a whopping 230 miles per gallon! Using the same EPA standards, a rival automaker, Nissan, reported that their all-electric Leaf would get 367 mpg.
Mind-blowing numbers, right? You would think the Volt or the Leaf will blow the 50 mpg Prius off the road. Not true in half of the country. The long and short of it is driving 100 miles in a Prius emits 40 lbs of CO2e across all states whereas driving 100 miles in a Volt in Kansas emits 53 lbs, in California 19 lbs, and in Massachusetts 25 lbs. When electricity comes from burning coal, the Prius is hands-down greener than charging your Volt from the garage outlet.
While we applaud products that reduce our dependence on foreign oil, it’s time to put the greenwashing brakes on the spin that electric cars are the environmentally friendliest throughout the land. Just because you can’t see the fossil fuels being burned to make electricity doesn’t mean they’re not being burned when you’re on a dirty grid. Let’s put the pedal to the metal on a new renewable energy infrastructure. Then plug-in hybrids and electric cars will be greener than ever.
For this comparison we used:
2010 Toyota Prius – 50 miles per gallon
Chevrolet Volt – 25 kWh per 100 miles (running on electric only)
Gasoline emissions – 19.777 lbs CO2e / gallon (based on US EPA GHG Inventory)
Electricity emissions – year 2005 data from eGRID2007 v1.1
K said,
August 25, 2009 @ 12:16 pm
Very eye opening, especially coming from a committed East Coast Prius owner like Rich! Is this the first time these numbers have been crunched? I would think Chevrolet and Toyota would be interested in this info. You should send it off to them! Not to mention national publications…
Great job. Cool stuff.
Matt said,
August 25, 2009 @ 3:20 pm
And if nuclear, solar, hydro, or wind power are used to charge the volt the reductions in CO2 go down to nearly 0. So lets continue to move the grid to the above. Then any plug-in will have an advantage.
Can the prius match that?
carolyn said,
August 26, 2009 @ 10:35 am
Matt, you’re absolutely right. In places where the electricity already comes from low-carbon sources (like here in Vermont), the Prius is handily beat by the Volt even today. And as we work to green up the grid all across the country, electric vehicles will start outperforming even the most efficient hybrids everywhere.
iafb83 said,
August 26, 2009 @ 8:41 pm
Great post! It’s about time people begin spreading the truth of the technology as opposed to the marketing gimmicks that sells cars. I’m not against electric cars by any means, but awareness is key to a better planet.
McLovin said,
August 26, 2009 @ 9:23 pm
Try recalculating using global GHG emissions for the gasoline and you will be shocked. Factor in the electricity used in refining the oil while you’re at it (and the amount of CO2 spewed by coal fired power plants to run the whole process).
Remember even dirty coal has a pretty quick trip to the power station. Oil is brought in from afar, then highly processed, again transported, then finally shows up in the prius gas tank.
In the end, even dirty coal makes the oil-burning prius look like an environmental disaster.
You all know the logical answer to this mess.
Ex-EV1 driver said,
August 26, 2009 @ 10:00 pm
Rich,
Don’t let an infant’s early limitations screen you from seeing that it can grow up into a great contributor to society.
I agree with many of the commenters above in wanting to focus on the fundamental fact that the Volt will only get cleaner as the grid cleans up.
The Prius is a great step towards sustainability but it can never be sustainable. We must move on.
Electric Vehicles clearly have a sustainable future, primarily because of their great efficiency and their ability to use nearly any raw energy source.
Ian said,
August 27, 2009 @ 11:25 am
@McLovin
For this analysis we assumed the embodied emissions of gasoline and electricity feedstock fuels were roughly balanced. According to a 2005 well-to-wheels report using the Argonne National Laboratory’s GREET model, embodied emissions increase gasoline’s impact by about 27%. That’s a significant bump, but I’m inclined to think coal isn’t much better. Even if it is, our original analysis doesn’t include electricity loss during charging – a 2009 ANL report on plug-in hybrids assumes 85% charger efficiency. That alone would cut the impact of embodied gasoline emissions by half. Bottom line: although a complete analysis might shift the balance in favor of the Volt, it wouldn’t negate our basic finding.
But as you say, we both know the solution is to clean up our electric grid.
Steve said,
August 27, 2009 @ 12:54 pm
Sorry, but things aren’t that simple. Another effect of EV is to reduce emmisions which cause illness and health costs for humans. This is important in cities. These problems are more complex than they seem.
Kelli Garner said,
September 25, 2009 @ 10:36 pm
Thats very good to know… thanks
CC said,
September 27, 2009 @ 12:03 am
This is not true, you have to account for the energy it takes to pull oil out of the ground, the environmental damage and then ship the oil from Saudi Arabia to Southern California or Chicago. Plus the Prius is built in Japan and China so you must ship the cars here to North America on diesel ships, that are not low sulfur. Then there is the fact a prius is garbage to drive, the Volt might be all wrong too but I have not driven it yet. The prius is wrong because it is like a rolex, it is like hey look at me (I sent my money overseas to Asia) I do something good for the environment, It you want to do something good for the enviroment, sell your car move into a city like Chicago, New York, Boston, DC or Toronto and walk to work and take the train to visit family and have them pick you up from the nearest stop. The Prius is all in all a garbage car that gets 51 mpg, the 1985 Honda Civic DX Hatch back with the 1.5L cost $1500 used, 45mpg, and its far more fun to than a Prius, I drive a lot of cars I know. This doesn’t even address the fact that the plugin prius is going to be sold in the US. The problem most hybrids with the exception of the Ford Fusion, Lexus LS and (I don’t know but I’ve been told) the new Mercedes S class hybrid, but the problem is hybrid are generally garbage. Buying new cars are not green, buying a bike is, sorry…Prius suck to drive.
Ian said,
September 28, 2009 @ 2:52 pm
@CC
You’re right that riding a bike is much better than driving, and buying a used car is better than buying new. Our goal with this post was to point out two things:
1) If your electricity comes from fossil fuels, zero tailpipe emissions doesn’t mean zero greenhouse gas emissions
2) Some parts of our electric grid are dirtier than others.
We understand that this is a relatively simple analysis, leaving out embodied emissions. We think that approach was justified for several reasons:
As I pointed out in my reply to McLovin, including the embodied emissions of oil, coal, and natural gas might tip the balance slightly in favor of the Volt, but wouldn’t have a huge impact.
The distance from the factory to a vehicle’s point of sale affects emissions, but so does the mode of transportation. Trucking emits 10 times as much as shipping and 3.5 times as much as rail. So if you live on the west coast, you could be better off buying a car from Japan than a car from Detroit. Either way, driving a car emits far more than manufacturing it. Honda and Toyota claim that production, transportation, and recycling account for 20-30% of a vehicle’s life cycle emissions. We assumed the embodied emissions of the Volt and Prius were equal.