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I would have never suspected this:

Carnegie Mellon University researchers have compiled information about the lifecycle greenhouse gas emissions of various EVs based on where they're charged, as compared to gasoline-powered vehicles. The researchers looked at the Nissan Leaf, Chevrolet Volt, and Prius Plug-In Hybrid versus the gasoline-dependent Toyota Prius hybrid and the stop-start-equipped Mazda3 with i-ELOOP and compared grams of CO2 emitted per mile.

Throughout the country, the Chevrolet Volt has a larger carbon footprint than the Toyota Prius, but a smaller one than the Mazda3 in a lot of urban counties in the US. The Prius and Prius Plug-In are relatively equal across the US.

 

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Depends on your electricity source. Doubtful a Prius can come close to either of our Volts with solar and very little gas.
 

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The grid data is from 5-10 years ago.
It also relies on a HVAC temp of 72 Degrees. Or in other words, is largely dependent on the driver behavior.

I don't doubt that this gave a general overview that was accurate in 2009, but it is off by a lot for the current grid.

In addition, it only applies to those charging off the grid, immediately when they get home from work, which almost no EV owners do. Once again though, it can vary based on user behavior.

If one is concerned about environmental aspects, a Volt, or any full BEV can be far cleaner than any ICE vehicle. Or it can be a little cleaner. Or, if someone isn't concerned, it can be dirtier than a Prius. However, it will still be cleaner than the fleet average vehicle.
 

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Vermont power generation is 99% non CO2 emitting. How can a leaf, which generates no CO2 directly and runs on electricty generated from 99% non CO2 sourcse produce more CO2 than a gas powered Prius. Its not Possible. Was this study funded by the Koch brothers?.
 

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ah ha!, quick review of the study shows it was funded by "Toyota Motor Corporation, and the Center
for Climate and Energy Decision-Making (CEDM)" I wonder why the Prius did so well against it competitors.
 

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All gasoline consumption is ignoring the electricity to produce and pump it and its energy sources. If we take every point from the well to the vehicle, there is more energy used to produce the gasoline than the energy in the gasoline itself. Hydrogen has even worse results. Besides, an EV such as the Volt used less energy to charge than an A/C running at the same time.

So if they want to produce numbers and graphs that tell the truth, they can contact ME!
 

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The more i read this study the angrier i get. This is pure propaganda. This regional study is using the same CO2/Mwh for power generation for all regions. It is assuming the BEV vehicles manufacturing produce 2.8 times the CO2 of a conventional car.
 

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One of the major problems with study data for tech is that they are usually _old_ data and technologies improve.

Then there are assumptions: grid average - no good, obviously. Local average: not good because a lot of charging is done at night, and nighttime generation is not the same. Etc, etc, etc.
 

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Demonstrably false. Not even close. The only way to get this result would be to assume very little of your driving is in CD Mode. Sometimes I think academics are also susceptible to the appeal of breaking the "man bites dog" story.

For example, where I am the grid number is 651 lbs per MWh. So if the Volt never turned the engine on and went 12K miles annually, it would use 330 kWh of electricity per month would produce 2724 lbs of CO2 annually. If the Volt never plugged in and went 12K miles it would produce 6000 lbs of CO2 annually. A Prius would produce 4800 lbs of CO2 annually. Very hard to see how the Prius even gets close. Just do the arithmetic: .8 X 2724 + .2 X 6000 = 3379. That's almost 1500 lbs less CO2.
 

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I bought the Volts because they are great cars, not to save the planet.

However, their report is certainly BS for Volts, even counting for selective stats.

It's 317 grams of greenhouse gases per kWh including distribution losses where I live, which is Car Central (Southern California).

While I can exceed the EPA advertised range in the 2016 Volt, I will use it anyhow. The EPA says the Volt gets 3.2 miles per kWh at the house power meter.

So, the Volt spews ...

100 grams of CO2 per mile when running off Southern California Edison juice.

So using the same EPA testing cycle and assuming it's really attainable on an import, the 2016 Toyota Prius spews ...

205 grams per mile.

You would have to drive a LOT of gas miles in the Volt to catch up.

That's EPA data for 2016 and powergrid data for 2016 in the most car dense area on the planet.
 

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All gasoline consumption is ignoring the electricity to produce and pump it and its energy sources. If we take every point from the well to the vehicle, there is more energy used to produce the gasoline than the energy in the gasoline itself. Hydrogen has even worse results. Besides, an EV such as the Volt used less energy to charge than an A/C running at the same time.

So if they want to produce numbers and graphs that tell the truth, they can contact ME!
Actually, they do take into account upstream energy use for gasoline. It took some digging, but on that it appears accurate.

One of the major problems with study data for tech is that they are usually _old_ data and technologies improve.

Then there are assumptions: grid average - no good, obviously. Local average: not good because a lot of charging is done at night, and nighttime generation is not the same. Etc, etc, etc.
They appear to use localized data, however, it is very old data.
Overall, I'd say the paper is worthless for judging GHG emissions today.
If you want to compare GHG emissions from 8-10 years ago (when the Volt wasn't even on the road) it holds limited value.
 

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Actually, they do take into account upstream energy use for gasoline. It took some digging, but on that it appears accurate.



They appear to use localized data, however, it is very old data.
Overall, I'd say the paper is worthless for judging GHG emissions today.
If you want to compare GHG emissions from 8-10 years ago (when the Volt wasn't even on the road) it holds limited value.

They only use localized data when it supported their agenda. They used average data when it did not. The whole purpose of the study was to determine where Prius CO2 emissions were less than PHEV/BEV. However, they ignored the largest contributing factor affecting regional CO2 emissions (CO2/Mwh for electricity generation).
This is not by accident. This study is intentionally miss-leading.
 

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Maybe these "Acadidiots" should look at the recent data and the latest trends.

Here is a recent report from EIA on power generation by fuel type.

https://www.eia.gov/electricity/monthly/update/resource_use.cfm#tabs_gen-1

In every region of the country, coal consumption is down. In the Northeast, where I live, coal consumption for power generation is almost zero. We also get almost 50% of our power from nuclear, hydro, and renewables. I haven't seen a report yet for 2015, but I guess we are near 650 lbs of CO2 per MWh.

When I drive on electricity, I average about 125 MPGe (this number in the DIC includes charging losses). So for 1000 miles, I use ~ 270 kWh [(1000/125)*33.7]. This equates to (270/1000)*650 or 175 lbs of CO2.

For a 50-mpg hybrid, this same distance requires 20 gallons of gasoline at 24 lbs of CO2 per gallon (includes extraction, transportation, refining, and distribution), thus emitting 480 lbs of CO2.

Therefore, in my locale, my CO2 emissions on electricity are only about 37% of those of the 50 mpg hybrid.
 

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Mellon makes a fundamental error. Basing long-term recommendations on short-term current conditions. And they compounded their mistake by using old grid data. Buying a Prius LOCKS YOU IN to a fixed CO2 level and oil dependency for the 10-year life of the car. The grid of 2020 will be way different than the current grid. Legacy coal plants are dropping like flies in favor of new NG plants. A Volt ADAPTS TO GRID UPGRADES to reduce CO2 emissions as the grid changes PLUS gives the owner the FREEDOM to invest in their own CO2-FREE PV system to charge the vehicle. A Prius? It has "OK" CO2/mile, but all the PV in the world won't improve that. The only thing that will further reduce its emissions will be to take it TO THE JUNKYARD and crush it, then go out and buy an EV that charges off renewable power.
 
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