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-   -   Electric vehicles (EVs), their emissions, and future viability (http://forums.tdiclub.com/showthread.php?t=448191)

Mark SF September 20th, 2015 08:53

Electric vehicles (EVs), their emissions, and future viability
 
Quote:

Originally Posted by MrSprdSheet (Post 4891517)
+1

And while the comparisons of pollutants, like NOx and CO2 are made, realize that the higher CO2 from marginally more fuel consumption doesn't materially change what is a high CO2 per mile figure. It is still going to be about half a pound per mile. The growing electric competition pushes closer to .3 lbs per mile (@3mp_kwh, on a 1,000lb/MWh US electric mix).

The point vs. electrics would be that you always need a second car for longer trips. In my case, I could have an electric car for commuting, and another car for the weekends - or I can have one car, the TDI. Considering all the energy that goes into making a car, I'm pretty sure that having one efficient vehicle comes out ahead.

bhtooefr September 20th, 2015 08:59

Well, there are plug-in hybrids as well. And, sure, a better one (let's use the 2016 Volt) will probably do a little worse on regular unleaded (assuming a depleted battery) on the highway than a diesel, but a diesel also puts out about 14% more CO2 per gallon, and I doubt the 2016 Volt will do 14% worse fuel economy than a post-recall CBEA/CJAA. (At 42 mpg highway for the Volt, the TDI would need to get nearly 48 mpg. Sure, the Volt's a hybrid, and it might not get 42 mpg highway in reality, but I'd also not expect a post-recall CBEA or CJAA to get 48, I'd expect closer to the EPA ratings of 40-43.)

Then, there's city mileage that should be much better for something like the Volt, and then there's 53 miles of electric range at electric (low) CO2 emissions.

Mark SF September 20th, 2015 09:12

Quote:

Originally Posted by El Dobro (Post 4891603)
That's why I bought a Volt.

I thought about the Volt, but the high sticker price put me off, and the fact that it's based on the GM Astra - hardly a car with a reputation for being inspiring to drive. I think the VW TDIs sell partly because of their driving dynamics.

I read that the battery on electric cars typically adds a premium of about 50 g/km of CO2, as they are so energy-intensive to manufacture.

bhtooefr September 20th, 2015 09:15

That premium would be amortized over the life of the battery, though, so really we need what the actual CO2 cost of the battery is, not a "g/km" figure.

Mark SF September 20th, 2015 09:18

That 50 g/km was the figure when the energy taken to make the battery was amortized over the battery life. Or are we saying the same thing?

bhtooefr September 20th, 2015 09:18

We're saying the same thing, but what's the battery life estimate, and what's real-world battery life?

Mark SF September 20th, 2015 09:20

Good question.

I'm pretty convinced that the TDI made sense, for my mix of driving conditions, as I bought it. Whether it continues to make sense after VW have finished with it, is another matter. The fact that it was fun to drive was a major factor. I find it hard to imagine joining the hybrid set, given how most of them drive. It's like they've never done it before. The fact that I didn't need to putz along at 55 mph to get good fuel economy, or drive around on a 120 degree day with the windows open because my battery range is so marginal (saw this the other week, a $120K Tesla in 105 degree heat and he's driving with all the windows open), were major factors for me. TDI is the efficient car for people who can drive.

SageBrush September 20th, 2015 11:49

Quote:

Originally Posted by Mark SF (Post 4891607)
I read that the battery on electric cars typically adds a premium of about 50 g/km of CO2, as they are so energy-intensive to manufacture.

Amazing what one can read on the internet.

Mark SF September 20th, 2015 11:51

Are you saying that large batteries are not energy intensive to produce?

Here's a report, the picture is quite complex as it depends on the electricity generation mix used to make the car, and to power it :

http://shrinkthatfootprint.com/electric-car-emissions

One point : a Volt is the worst case really for manufacturing emissions, as its a gasoline car with a large battery.

SageBrush September 20th, 2015 12:59

Quote:

Originally Posted by Mark SF (Post 4891748)
Are you saying that large batteries are not energy intensive to produce?

I am saying that 50 gram CO2e/mile emissions due to the battery in EV use is FUD.
Lots of source data is available for free reading. E.g.,
http://www.environment.ucla.edu/medi...012-rh-ptd.pdf
Quote:

Based on our findings in Ishihara et al., Nemry et al., and Staudinger and Keoleian, we determined that battery recycling required 31 MJ/kg, which, with a 300 kg battery per vehicle and operating under the assumption of 1 battery with partial replacement per vehicle life, equates to 13950 MJ of energy required to recycle the battery. We calculated, based on an emission intensity of energy of 1.51 kg CO2 per kg of battery, that this would lead to emissions totaling 680.76 kg CO2.
For context, a diesel emits around 10 Kg CO2 per gallon.

OR


Argonne National
http://i.imgur.com/tFWDpov.jpg

For a unitary example then, a grid that produces 1 pound of CO2 per kWh generated (3412 btu) would thus lead to (65/3412 = 0.01905041) pounds per mile from battery related lifecycle costs. This works out to 8.64 grams per mile of CO2.

Mark SF September 20th, 2015 13:02

What has a table showing the energy required to re-cycle a battery, got to do with the energy required to make a battery? You do understand the difference between making and re-cycling, don't you?

Here is the nearest thing I can find to an unbiased report :

http://shrinkthatfootprint.com/wp-co...ull-Report.pdf

They are assuming that an electric car costs 70 g/km to make, and a gasoline one costs 40. The conclusion is that an electric car, over its lifetime, emits the same carbon as a gasoline car that does 43 mpg, based on US electricity mix. That would be the same as a diesel car doing about 50 mpg, I think.

Mark SF September 20th, 2015 13:25

[QUOTE=SageBrush;4891799]I am saying that 50 gram CO2e/mile emissions due to battery manufacture is FUD.
Lots of source data is available for free reading. E.g.,
http://www.environment.ucla.edu/medi...012-rh-ptd.pdf

In figure 7 of the report that YOU reference, it shows a figure of 0.039 to 0.048 kg/mile of CO2, due to battery manufacturing, for the electric vehicle. This is 39 to 48g per mile, very close to the 50 that I quoted.

It's very kind of you to back up my point with solid data.

To put it another way, the CO2 per mile for the total energy for manufacturing the gasoline car is about 13 g/mile. The C02 per mile for manufacturing the electric car is about 55 g/mile.

My point is not that electric cars aren't more efficient, but that they are not as efficient as they seem, purely based on re-charging costs.

bhtooefr September 20th, 2015 13:34

http://www.dailykos.com/story/2013/0...-CO2-Footprint has some discussion of various CO2 footprint questions regarding EVs, for what it's worth. GREET is leaning towards 5.1 kg CO2 per battery kg, and the Volt's battery is 183 kg, for 933.3 kg embodied CO2 in the battery.

That's 104.8 gallons of gas, or 91.95 gallons of diesel, which means that a TDI has a very, very low head start indeed. Let's say the TDI gets 50 mpg (which, after this, it won't, and in the city it never did), that's only a 4598 mi head start.

SageBrush September 20th, 2015 13:40

Quote:

Originally Posted by Mark SF (Post 4891805)
What has a table showing the energy required to re-cycle a battery, got to do with the energy required to make a battery?

Everything, if you want to consider a lifecycle analysis.
Assuming every battery sources from raw materials is a flawed analysis, but the results are not *that* different and certainly no where near 50 grams CO2 per mile.

I thought you would complain that the second reference analyzed a PHEV20. I picked it out of personal preference for that auto config, because the study was so well done and written up, and because the only significant manufacturer of huge battery EVs is opening a factory in NV that will be carbon free.

bhtooefr September 20th, 2015 13:43

Carbon footprint of EVs
 
This thread was started to continue a discussion from the thread on Volkswagen Clean Air Act violations, and all posts before this point (and a couple from after this point) were merged in from that thread.

I don't want to risk breaking the thread (this is the original OP, and I THINK I can safely delete it, but I don't want to risk it), so I'm leaving this post in.


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