Absolute vs relative environmental impact - an example with a TDI I own

[tikal]

There was discussion recently about what is 'bad' pollution or what level of pollutant is 'bad' vs. 'good'.

How about using relative terms normalized per mile/km driven? We recently acquired a 2015 Passat TDI (everything stock) so wxman was kind to provide this:

2015 VW Passat TDI vs Toyota Camry Hybrid

"Apples to apples", right?

 

[Windex]

Sketchy graph gonna be sketchy...

No sources listed for any of the data

No units stated for the vertical axis

 

[oilhammer]

I'm with Windex, not really sure what we are looking at here.

And what about the type of driving in addition to the age/mileage of the car? And what about the thing required to keep it operable.

I mean, we do Toyota hybrid battery replacements all the time. Does that get included in this?

Or is that not included, because it typically occurs after 150k miles, which is often that made up intended "lifecycle" for a car?

And going forward, this is sort of a moot point. Not only can we not buy a new Passat TDI today, we can't even buy a Passat of any kind today. But Toyota is still happily selling Camry Hybrids (along with hybrid versions of the Avalon, Corolla, Highlander, and RAV4... and now ALL the Siennas are hybrids, along with whatever Prius models they still have on offer... the C and V are no more, though).

But alas, Volkswagen does have that hideously ugly EV that costs nearly $40k (seriously, Volkswagen's current North American offerings are just pathetic).

 

[IndigoBlueWagon]

This is the last production year for the Passat, so there might still be a few new ones around. And the ID.4 costs closer to $50K than $40K at most dealerships.

The emissions numbers can be manipulated in so many different ways as to probably not be of any use. I think one thing you can be sure of is it's better to continue to maintain and drive what you have than replace it with something new. Unless you're driving a V10 F350 or similarly inefficient vehicle.

 

[wxman]

I can hopefully clarify that graphic since it's mine.

There are no units on the vertical axis since it's on a relative scale.

I used Argonne National Laboratory's GREET model (https://greet.es.anl.gov/) to determine emission rates throughout the entire life cycle of the vehicles. The default vehicle mass and fuel economy were modified based on actual data of the 2015 Passat and 2015 Camry hybrid:


2015 Passat SE TDI - 3408 lbm (NADA); 35 mpg combined = 31.38 mpgge
2015 Toyota Camry Hybrid LE - 3485 lbm (NADA); 40 mpg


Used default exhaust emissions for each vehicle. Damages from each phase of the lifecycle are based on the latest damage cost factors available:

Source: https://www.eea.europa.eu//publications/the-first-and-last-mile (Table 2.1 on page 24)


Here are the actual damages as calculated:


Camry - 0.5521 (PTW) + 0.0883 (feedstock) + 0.1654 (Fuel) + 0.5454 (vehicle) = 1.3512 ¢/mi (total non-GHG EDX)
Passat - 0.6001 (PTW) + 0.1389 (feedstock) + 0.0760 (Fuel) + 0.3687 (vehicle) = 1.1837 ¢/mi (total non-GHG EDX)

 

[oilhammer]

Once again, what is the definition of "lifecycle" in this situation? It seems pretty meaningless (to me) without that factored in. And even then, how do you accurately factor this in when a 2015 TDI is a unique engine (for us), and doesn't really have a good database to draw from to get an idea of what the real costs are?

I mean, if a CVT-equipped Nissan only has a 50-50 shot of even making it to 150k before the transmission dies, wouldn't that skew the results? I use that example, because those die so much, doing a Sentra today that didn't even make it 80k miles. Pretty sure there is an environmental impact to manufacture another transmission assembly and ship it all the way from Japan.

 

[wxman]

There definitely is an environmental impact for any early replacement equipment.

The life cycle for passenger cars in GREET is 173,151 miles (it's based on 15 year useful life at whatever the average miles/year are calculated by EPA).

Not sure how replacement parts are handled in GREET. There is extensive documentation for the GREET model on Argonne National Laboratory's web site at https://greet.es.anl.gov/list.php if you are interested.

 

[oilhammer]

See, didn't know that. That helps, thanks. So that is a fairly generous range, probably less than most new TDI buyers would have wanted, but more I'd say than a lot of new Camry hybrid buyers.

I can tell you that 15 years for me and a lot of the folks around here would be WELL over 173k miles. I do probably about 50k a year myself alone, usually spread out over several vehicles.

Since the 'manufacturing' portion of that chart is fixed, it would over time represent a smaller and smaller portion. And if you buy used, that would essentially be nil, although obviously someone did build/buy it.

But clearly, even with this model that has some consistency and parameters, the overall environmental impact of anything car-related is far more malleable and diverse than could realistically be gathered. Which is what I was trying to say in another thread before our local EV zealot came and crapped it out of existence. At least we've got a respite from him.

 

[tikal]

Thanks wxman for the needed clarifications.

Certainly is fair to ask questions. If someone has a better, more comprehensive life cycle environmental model(s) to compare these or other passenger vehicles please do share.

To me, Argonne National Laboratory's GREET model (https://greet.es.anl.gov/) is steps ahead of comparing just MPG or liters per 100 km or NOX emissions per mile/km, etc.

 

[wxman]

See, didn't know that. That helps, thanks. So that is a fairly generous range, probably less than most new TDI buyers would have wanted, but more I'd say than a lot of new Camry hybrid buyers....

Sorry, I should have included the assumed useful life miles of the vehicles in my initial post.

Here is a screen capture of the summary of emissions from vehicle manufacture of various vehicle technologies from GREET (GREET2):

 

[IndigoBlueWagon]

Are these actual vehicles? For example, is there such a thing as an ICEV that's made of "lightweight material"? And what would that material be?

 

[wxman]

They're default "mid-size" passenger cars.

"Lightweight materials" are those vehicles made with higher levels of e.g., aluminum and carbon fiber-reinforced plastic.

 

[turbobrick240]

Is that Camry a plug in hybrid? I'm guessing not. It would be interesting to see a similar comparison against a plug-in hybrid that does half it's mileage in electric only mode.

 

[oilhammer]

And there again, that can skew the results, because it would seem that type of use would shorten the battery life even further. I know the plug-in Prius uses a bigger (and more expensive) high voltage battery.

 

[gulfcoastguy]

I'm with Windex, not really sure what we are looking at here.

And what about the type of driving in addition to the age/mileage of the car? And what about the thing required to keep it operable.

I mean, we do Toyota hybrid battery replacements all the time. Does that get included in this?

Or is that not included, because it typically occurs after 150k miles, which is often that made up intended "lifecycle" for a car?

And going forward, this is sort of a moot point. Not only can we not buy a new Passat TDI today, we can't even buy a Passat of any kind today. But Toyota is still happily selling Camry Hybrids (along with hybrid versions of the Avalon, Corolla, Highlander, and RAV4... and now ALL the Siennas are hybrids, along with whatever Prius models they still have on offer... the C and V are no more, though).

But alas, Volkswagen does have that hideously ugly EV that costs nearly $40k (seriously, Volkswagen's current North American offerings are just pathetic).

Read while sitting in one of those “hideously ugly EVS”. Which is a VW rather than a Toyota. 36,000 miles on the clock.

 

[tikal]

Just to re-focus this thread and I should have been more clear from the get go: I was looking for a used efficient, roomy (specially in the back seats), passenger car with a certain limited budget (less than $20K) and I narrowed my choices to a 2015 VW Passat TDI or a 2015 Toyota Camry hybrid. Then I ask the question, which one has the lowest normalized environmental impact: manufacturing the vehicle, emissions, the whole nine-yards ...

The above is a reasonable approach, not perfect, but better than just comparing MPG in my view.

 

[turbobrick240]

Well, if you're buying used I would contend that it is only the operational phase (and not manufacturing) emissions that matter. The car has already been made after all, and buying a used one shouldn't result in more new ones being built. So the manufacturing related emissions are more or less inconsequential.

 

[IndigoBlueWagon]

Well, if you're buying used I would contend that it is only the operational phase (and not manufacturing) emissions that matter. The car has already been made after all, and buying a used one shouldn't result in more new ones being built. So the manufacturing related emissions are more or less inconsequential.

Not sure how you figure that. I would think that the manufacturing impact would be spread over the useful life of the car, no matter how many owners it has. And most people who buy a car are selling or disposing of a car, and most people who sell a car are buying another. So if purchasing used doesn't result in a car being manufactured for you, it still has impact somewhere in the ownership chain.

 

[ticaf]

Keep in mind that whatever numbers you'll find are not necessarily accurate. And figuring out the whole picture over the life of the car including recycling is not an easy task.

 

[turbobrick240]

Not sure how you figure that. I would think that the manufacturing impact would be spread over the useful life of the car, no matter how many owners it has. And most people who buy a car are selling or disposing of a car, and most people who sell a car are buying another. So if purchasing used doesn't result in a car being manufactured for you, it still has impact somewhere in the ownership chain.

The manufacturing impact is what it is however many miles are put on the vehicle. More miles is better insofar as that it probably results in fewer new cars being made. When I bought my Golf new in 2011 that info went straight to VW and they knew to increase Golf output by one vehicle. When I bought my used 2010 Golf in 2018, VW didn't know and didn't make any adjustments to their Golf manufacturing output as a result. The same applies to a 2015 Passat or Camry. Yes, buying a used car has a very generic effect on the auto market, but it certainly isn't model specific.

Edit: Since they aren't making a TDI Passat for this market any longer, it's quite clear that buying a used Passat can't possibly have any impact on new TDI Passat manufacturing.

 

[oilhammer]

I don't think anything Volkswagen-related here has much of an impact. Their US market share is so pathetic. It hovers around 2%. Which is an amazing figure given that this is the largest (by far) single car market on the planet, and yet Volkswagen is still one of the largest car manufacturers on the planet. Which tells you that they must sell a crap load of cars almost everywhere else but here.

 

[IndigoBlueWagon]

Not to take things off track, but if VW would offer vehicles that brand enthusiasts want to buy, they'd sell more cars. Instead they move towards bloated generic CUVs and SUVs that aren't competitive in their segments, and aren't of interest to brand loyalists. So they lose on both counts.

They build interesting and good cars. They just don't sell them here.

And speaking of Passats, this is what I'm driving today.

Probably not a lot of environmental impact for making this choice.

 

[tikal]

I would agree with post # 18 and spreading the environmental impact over the life of the vehicle. As an example, So I bought the vehicle being 7 years old and I am going to keep it another 7 or 8 years, I would do some sort of weighting by years.

All in all it is a close call. The diesel advantage, of course, comes with the torque so the Passat TDI gives me 236@1,750 and the Camry hybrid is 156@4,500 (source https://www.motortrend.com/). WE do a lot of camping and mountain driving with a cargo carrier so that is definitively a factor for us. In the future there might be some light towing like this one https://timberleaftrailers.com/classic-teardrop-trailer/ so the extra torque is definitively desired in my view.

 

[gulfcoastguy]

Just a point of interest about the VW EVs. The battery comes with 12 individual modules. Unlike some manufacturers the battery packs are screwed together aluminum. If the range stops to drop to unacceptable levels , you drop the battery, test the modules and replace the one or 2 worst ones. VW already has a company and plant setup to recycle old battery packs with 95% of the materials available for reuse. Having an aluminum battery pan means that it can eventually be recycled unlike other manufacturers glued plastic battery packs.

 

[oilhammer]

We were doing that with Prius batteries 15 years ago.

But that was largely due to the ridiculous price of replacement battery assemblies. Since the impending lawsuit, Toyota caved and set up their exchange program for them. Now they are about 1/3 the price they used to be, and they recycle as much as they can.

Toyota didn't sanction any cell replacements, despite having a very detailed OBD regimen to allow for diagnosis and such. Funny how some 50+ DTCs that the hybrid battery ECU can store all lead to the same solution: replace the battery.

 

[turbobrick240]

I would agree with post # 18 and spreading the environmental impact over the life of the vehicle. As an example, So I bought the vehicle being 7 years old and I am going to keep it another 7 or 8 years, I would do some sort of weighting by years.

All in all it is a close call. The diesel advantage, of course, comes with the torque so the Passat TDI gives me 236@1,750 and the Camry hybrid is 156@4,500 (source https://www.motortrend.com/). WE do a lot of camping and mountain driving with a cargo carrier so that is definitively a factor for us. In the future there might be some light towing like this one https://timberleaftrailers.com/classic-teardrop-trailer/ so the extra torque is definitively desired in my view.

I think your torque preferences are a much more sensible reason to choose the Passat, rather than anything related to the manufacturing impact that happened over 7 years ago.

 

[wxman]

There's a relatively new European vehicle life cycle called "carculator" (https://carculator.psi.ch/). There's an on-line version that free to use, just need to register. Based on this model, here are the the results using the default parameters:

This appears to agree fairly well with the GREET results. "Cost of ownership" was deselected since that cost is mainly borne by the owner.

 

[turbobrick240]

One of the not so great things about hybrids is that you have the impacts from manufacturing both ICE and electric powertrains for one vehicle. Even though a 2015 model year vehicle is distant enough from today's manufacturing to have very little correlation with current manufacturing emissions.

 

[turbobrick240]

There's a relatively new European vehicle life cycle called "carculator" (https://carculator.psi.ch/). There's an on-line version that free to use, just need to register. Based on this model, here are the the results using the default parameters:

This appears to agree fairly well with the GREET results. "Cost of ownership" was deselected since that cost is mainly borne by the owner.

Carculator is a pretty interesting tool. I just checked out their comparison of "new" 2020 midsize gas/diesel/cng/battery electric vehicles. The default setting only went up to 200k km, but I think that can be adjusted.

 

[wxman]

...The default setting only went up to 200k km, but I think that can be adjusted.

Yes it can, up to 400,000 km.