I have heard that the true CO2 costs of a Prius are greater than a Hummer, true?

Question

This concerns life-cycle costs. The batteries are the killer. If you consider over the life of the vehicle and all the CO2 emitted to make it, gas burned over it's life, and dispose of it...is a Prius actually worse than a Hummer? (we will all go electric eventually, still, let's not forget the total costs of things)

Answer 1

It's a hard one to measure.  By some accounts, 25% of a car's CO2 footprint occurs before it's been driven one mile.  I don't know how much energy it takes to make a Prius battery, but even if it is very high, there are a few things to consider:

The energy used doesn't have to emit carbon.  If the battery factory is wind or solar powered, the equation changes.  

Technology advances will make battery production more energy efficient.

The battery is recycled at the end of the day, so you have to take into account the longer material life.

While these technology advances can also apply to a Hummer, they will tilt the equation in favor of the Prius, since the argument is that the up-front impact is so large that it negates the lower gas mileage.  

There is a study that claims a Hummer is better then a Prius.  Called 'Dust to Dust' it claims to show the lifetime energy cost per vehicle of dozens of cars.  The Prius comes out poorly in this study, in part due to the high energy cost of extracting nickel for the batteries.  However, there are other battery technologies out there and if Toyota were to use a Lithium Ion battery instead, it might make a huge difference.  According to the report, the boxy little Scion XB is the most environmentally friendly car you can buy.  However, the report has been widely criticized for sloppy and inconsistent methodology.  

One dubious assumption:  a Toyota Prius was only projected to be on the road for 100,000 miles while a Hummer H2 was given 300,000 miles.  Japanese cars are famously more reliable then American cars, so there seems to be a gaping hole in this "study".

Answer 2

The "Dust to Dust" report is based on distorted numbers.

http://cnwmr.com/nss-folder/automotiveen...

Here is an excellent debunking of the Hummer hoax.

http://www.pacinst.org/topics/integrity_...

The deliberately wrong assumption is that the Prius is junked after 100,000 miles. The author of the report also says

"And as I pointed out in the past, the energy cost per mile is unequivocally going to decline for Prius over time as the technology continues to spread across other models and the disposal/scrap industry learns how to deal with its high-tech materials and components."

Answer 3

It's a close call.  You can do the analysis different ways and get different results.

But it's a little strange to claim you're doing a complete lifecycle analysis and then only consider CO2.  If you look at overall environmental and national security considerations (shipping bucks to the Middle East surely can't be in our interest), the Prius wins.

Answer 4

Hi,

This notion that a Hummer has a lower life cycle energy use and CO2 emissions  than the Prius was put out in a paper, and got a whole lot of Internet attention.

The paper turns out to be completely wrong.  This pdf gives a detailed rundown on the very very biased assumptions that led to CO2 conclusion:

http://www.pacinst.org/topics/integrity_...

Even the original author of the paper has admitted that his conclusion was wrong and widely misinterpreted.  

If you use the CO2 calculator at the link below, and compare the Hummer H2 to a Prius over a life of 200,000 miles, the numbers come out like this:

------------------------  Hummer      vs   Prius

CO2 emissions     229,333 lbs    vs 68,363 lbs

Gas Used  12,594 gals  vs 3,548 gals

The Hummer puts out 161,000!! lbs more CO2 from the gasoline it burns during its life than the Prius -- does it really make sense that the CO2 emissions associated with  making a few lbs of NIMH batteries would be more than 161,000 lbs?

Toyota also has an aggressive recycling program for the batteries that has been discussed here before.

I would be willing to bet that a fair comparison of the embedded energy and related CO2 emissions to produce a Prius are less than a Hummer.  After all, the Hummer weighs about twice as much as a Prius, and all things being equal, embedded energy depends on weight.  

It certainly clear that the CO2 emissions from a Hummer during its life are much much greater than a Prius.

The CO2 calculator is here:

http://www.hybridcars.com/calculator/

Gary

Answer 5

No no no no no... The hummer, for one, is a gas hog, and is horrible for CO2 emissions. Internal combustion engines only use 25% of the energy that gasoline is capable of making, while electric motors run about 90% efficiency. So the energy they do use is used alot more efficiently than the Hummer.

Another thing, the batteries do take a decent amount to make, but they last around 10 years. The pollution from one set of batteries does NOT outweigh the driving of a Hummer for 10 years.

Answer 6

"A 2007 Toyota Prius that drives 12,000 miles per year, for example, pumps 4,226 pounds of CO2 out its tailpipe, while a 2007 Hummer H3 adds 13,812 pounds for the same distance."

http://www.edmunds.com/advice/fueleconom...

I would be interested to see the source of the claim that the lifetime CO2 costs of a Prius exceed those of a Hummer.  The only similar claim I've seen is from "Dust to Dust" which was a study performed by a marketing company and concluded

"the total combined energy is taken from all the electrical, fuel, transportation, materials (metal, plastic, etc) and hundreds of other factors over the expected lifetime of a vehicle. The Prius costs an average of $3.25 per mile driven over a lifetime of 100,000 miles - the expected lifespan of the Hybrid.

The Hummer, on the other hand, costs a more fiscal $1.95 per mile to put on the road over an expected lifetime of 300,000 miles."

Somehow I guess people are equating this cost with environmental damage, or in the case of your claim, with CO2 emissions.  That's a flawed claim.

Also, since the study claims the lifetime of a Hummer is 3 times the lifetime of a Prius, the real analysis says that “owning a Hummer is better for the environment than owning three Priuses.”  No duh!  The main reason they claim a Prius has 1/3rd the lifetime mileage is because Prius owners drive less distance than Hummer owners.  So if the Prius owner bought a Hummer instead, they would only drive that 100,000 miles too, which would change the final calculation by a factor of 3!  That's a huge flaw in this claim.

You can read a debunking of Dust to Dust in the link provided below.  It concludes

"You could put any car in this same analysis and get the same results if it was based on new technology and people didn’t drive it much."

To answer your question, no, it's not true.