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

[aja8888]

Doesn't seem like a very significaant difference, and certainly not enough for me to want to tolerate the range limitations and charging time wasted on the Tesla . . . . Time is worth something as well!

When you get old enough, you realize time is all we have. It's important.

 

[VeeDubTDI]

Doesn't seem like a very significaant difference, and certainly not enough for me to want to tolerate the range limitations and charging time wasted on the Tesla . . . . Time is worth something as well!

It illustrates that the base car/drivetrain is more efficient than a diesel - a smaller, much less powerful diesel. In this case, the bulk of the added efficiency is probably from regenerative braking.

When powered directly by the grid instead of by a 40% efficient diesel engine (that's being generous), it's far more efficient, especially if your grid is clean.

 

[bizzle]

You have to keep things in perspective about this though. Sure, an EV gets less efficiency at higher speeds. A TDI may get higher efficiency at higher speeds (to a point, of course), but this is not because the TDI is working better at those speeds - the ICE has a lot of fixed losses in it just to have the engine running - so the faster you are going, the less those losses are relevant. It still is taking a lot more work to push your vehicle at 80mph than it is to push it at 50mph, no matter what the fuel source is - but the EV doesn't have near as much fixed losses, so you actually see the impact of speed more readily.
Actuall energy use, and most likely cost, an EV is going to use a lot less than an ICE, no matter what the speed.

My post (and concern regarding the Niro) was less about efficiency and more about not getting close to the stated mileage once traveling at highway speeds. If you are basing your calculations on those mileage claims, but they aren't achievable (the same thing happened with the Jetta Hybrid, which has been discontinued at least partly due to customers not realizing the savings they expected), then you will be sorely disappointed. If you are buying a PHEV for highway travel (and that seems to be the main reason for one over an EV), then you are better off with a TDI in my experience. My wife and I use the eGolf around town and the TDI for distance. Once the lease is up, we'll use the 98 TDI around town and the wagon for distance. The most savings are realized from a paid off vehicle (the main reason we even leased the eGolf was due to the dieselgate savings and VW's downturn along with avoiding a few thousand dollars in A/C repairs on the beetle).

On my 2000 TDI Beetle it was right around 59 mph with tach around 1900 rpm. I hit 56 mpg on a run to the Outerbanks and back in the same day, just over 600 miles. Lots of two and four lane state roads with 55 mph posted limit. I've not had the need or paths to find out the sweet spot for the JSW on a complete tank of fuel. I have noticed that it seems to return the best mileage (computer numbers) while cruising at about 73 mph.

It used to be said, although I don't know if it's true now or ever was, that the true north speedometer position was the most efficient. That would line up with right around the 60mph on your and my beetle, iirc. I have surpassed 60mpg (hand calc) in it driving from Oregon to Central California at about 60ish mph.

 

[nicklockard]

Doesn't seem like a very significaant difference, and certainly not enough for me to want to tolerate the range limitations and charging time wasted on the Tesla . . . . Time is worth something as well!

Umm, the Tesla used roughly the same amount of fuel. This means you are not accounting for the fact that the diesel genset is probably no better than 32% efficient at turning diesel into stored electrons. In other words, the well-to-well efficiency of the Tesla stomped the ever living crap out of the diesel because...well who the heck is silly enough to buy an electric luxury sedan and charge it with a diesel genset, outside of magazine article writers No logical person in real life.

 

[turbocharged798]

Umm, the Tesla used roughly the same amount of fuel. This means you are not accounting for the fact that the diesel genset is probably no better than 32% efficient at turning diesel into stored electrons. In other words, the well-to-well efficiency of the Tesla stomped the ever living crap out of the diesel because...well who the heck is silly enough to buy an electric luxury sedan and charge it with a diesel genset, outside of magazine article writers No logical person in real life.

The grid is not 100% efficient either, neither is a power plant. Line losses can be significant depending where you live.

 

[turbocharged798]

Found this:

According to the latest version of GREET (GREET_2016) and based on the most-recent EIA data for electricity generation mix in the U.S. (March 2016 - March 2017), well-to-pump (to-plug) is 45.5% efficient.

Petroleum-based diesel (ULSD) has a well-to-pump efficiency of 81.2% (gasoline 76.6%).

 

[bhtooefr]

.455 * .9 (grid efficiency times 90% car efficiency, which is probably low, given that regen can recover some) is higher than .812 * .4 (ULSD efficiency times 40% car efficiency), though. (And 40% is being generous to the diesel.)

 

[turbocharged798]

Not by much, about 7% difference.

 

[turbobrick240]

Except that 40% efficiency for a tdi is pretty much a best case scenario. It's closer to 30% efficient with normal driving.

 

[tikal]

Come on guys, we know that a light duty diesel is not going to be as efficient as an EV. The point is to have one of each in your garage and you have your bases covered. We keep falling in this false dichotomy in my view.

 

[kjclow]

Umm, the Tesla used roughly the same amount of fuel. This means you are not accounting for the fact that the diesel genset is probably no better than 32% efficient at turning diesel into stored electrons. In other words, the well-to-well efficiency of the Tesla stomped the ever living crap out of the diesel because...well who the heck is silly enough to buy an electric luxury sedan and charge it with a diesel genset, outside of magazine article writers No logical person in real life.

Unless you live in an area where power outages can last for days. If all you have is your ev, then you’ll have to charge by generator.

 

[nicklockard]

I love diesels, and I own one for the many reasons I love them: range, torque, the rush of acceleration from a well tuned (aftermarket modified) diesel is truly addictive. I even love the smells of NOx and diesel fuel.

But if someone gifted me a Tesla model S sedan, or the well-loved, lightly used model 3 could be had for close to what I've got into my 335d (about $14.5k) a few years from now, I would probably let the 335D beast collect dust for quite some time.

Until that time, I'll enjoy the **** out of this fast, nice car and laugh as other cars pull into the gas stations to refuel while I keep motoring.

I know that day will come when a smooth, tight, fast, killer looking electric will steal my heart and earn a spot in my garage, likely displacing diesels forever. 10 years? 5? 7? Some day.

 

[TDIMeister]

The comparison test in the Youtube video doesn't tell us much that we don't already know, but let's put in some numbers. It claims that the genset used 4.46 L to deliver 18 kWh of electricity.

The density of Diesel is about 840 g/L, thus 4.46 L equates to 3746.4 g.

3746.4 g / 18 kWh gives a BSFC of 208.1 g/kWh.

The LHV of Diesel is approx 43 MJ/kg, which equals 11.944 KWh.

Thus the generator has a genset-tank-to-plug efficiency of 40.2%.

We already know that a Diesel engine has best point BSFC just under 200 g/kWh corresponding with a thermal efficiency of about 42%.

The EV benefits from regenerative braking. Ostensibly the late model Volvo has engine start-stop, but it's well known that a Diesel engine is operating nowhere near its best efficiency point at part-load, particularly the mostly urban driving route in the test, in which everyone knows pure EVs and HEVs excel.

Another test emplying the same methodology that should be done is on an uninterrupted highway course of a good 500 km.

Lastly a comment on emissions: The premise of the video was to say that the same batch of Diesel fuel would be "cleaner" to be burned in a genset to charge a Tesla than is it to burn it in a Diesel car, based solely upon the relatively insignificant 7% difference in fuel consumption - aka CO2 emissions. Yet, the bigger picture truth is that an old genset, probably not even Tier-4 (2008/2013) stationary compliant by the looks of the age of the unit in question with no active exhaust aftertreatment to speak of, would produce far more CO, HC, NOx and PM than a contemporary Tier-2 Bin-5 Diesel car equipped with EGR+DOC+SCR+DPF (the comparison is a moot point anyway since Australia does not adopt US EPA emissions regulations).

https://youtu.be/tw-hHggAYFM

The Australian Electric Vehicle Association and the Tesla Owners Club of Western Australia charged a Tesla Model S P85D, which is not even the most efficient Tesla vehicle, using a diesel generator.They set out on a road trip with the vehicle and a Volvo V40, which is equipped with a T5 2L diesel engine, in order to determine the efficiency using the exact same fuel.

That's very interesting, especially considering the inefficiencies associated with charging the vehicle. Very nice comparison.

It illustrates that the base car/drivetrain is more efficient than a diesel - a smaller, much less powerful diesel. In this case, the bulk of the added efficiency is probably from regenerative braking.

When powered directly by the grid instead of by a 40% efficient diesel engine (that's being generous), it's far more efficient, especially if your grid is clean.

Umm, the Tesla used roughly the same amount of fuel. This means you are not accounting for the fact that the diesel genset is probably no better than 32% efficient at turning diesel into stored electrons. In other words, the well-to-well efficiency of the Tesla stomped the ever living crap out of the diesel because...well who the heck is silly enough to buy an electric luxury sedan and charge it with a diesel genset, outside of magazine article writers No logical person in real life.

.455 * .9 (grid efficiency times 90% car efficiency, which is probably low, given that regen can recover some) is higher than .812 * .4 (ULSD efficiency times 40% car efficiency), though. (And 40% is being generous to the diesel.)

Except that 40% efficiency for a tdi is pretty much a best case scenario. It's closer to 30% efficient with normal driving.

Come on guys, we know that a light duty diesel is not going to be as efficient as an EV. The point is to have one of each in your garage and you have your bases covered. We keep falling in this false dichotomy in my view.

 

[TDIMeister]

I tried to recreate the driving route in the video. There is a good amount of highway miles, but there's about 10 km unaccounted for that was off the screen in the Youtube vid.

https://goo.gl/maps/zXziyNeAbsk

 

[oilhammer]

I was just thinking that the diesel genset probably has nowhere near the emissions compliance hurdles to deal with that an on road vehicle does.

 

[TDIMeister]

Let's get down to the crux of comparing emissions OTHER THAN CO2 between a genset and a car.

A Tier-4 large genset of >560 kW (which may be fuelled not only with Diesel but also natural gas, etc.), is permitted 0.19 g/kWh NMHC (non-methane hydrocarbons), 0.67 g/kWh NOx and 0.03 g/kWh PM.
Source: Table 4, https://dieselnet.com/standards/us/nonroad.php#tier4

A T2B5 car is permitted 0.075 g/mile NMOG (non-methane organic gases * for diesel fueled vehicle, NMOG (non-methane organic gases) means NMHC (non-methane hydrocarbons), 0.05 g/mile NOx and 0.01 g/mile PM.
Source: Table 2, https://dieselnet.com/standards/us/ld_t2.php#bins

How do we convert kWh to miles? Normally, it is impossible to convert the two, but we have a clue that the Tesla used 18 kWh to cover 104.6 km / 65 miles. It is reasonable to assume that 18 kW is the energy to propel the 2.2 ton Tesla over the road course, not taking into account round-trip energy losses through the battery and power electronics, as well as any recovered from regenerative braking. So, it would not be unreasonable to apply the same 18 kWh to the ICE-powered car over the same road course.

Thus, 18 kWh over 65 miles gives 0.2769 kWh/mile.

Now, if we go back to the emissions limits above, we apply this factor to the genset:
0.19 g/kWh NMHC * 0.2769 kWh/mile = 0.0526 g/mile
0.67 g/kWh NOx * 0.2769 kWh/mile = 0.1855 g/mile
0.03 g/kWh PM * 0.2769 kWh/mile = 0.0083 g/mile.

Compare these again to that of the T2B5 car:
0.075 g/mile NMOG
0.05 g/mile NOx
0.01 g/mile PM.

I purposely chose to present the genset case in the most favourable light possible so that I would not be accused of bias; the latest standard and the largest size (giving the lowest per kWh values). If I were to do the same on a genset of the actual size in the video (30 kVA =~ 30 kWe) and estimated age, the results would show that the genset is in fact over an order of magnitude dirtier in HC+NOx and nearly an order of magnitude dirtier in PM!!!

Edit to add 30 kWeTier-4 (2008) genset emission data:
7.5 g/kWh NMHC+NOx * 0.2769 kWh/mile = 2.077 g/mile vs T2B5 0.125 g/mile NMOG+NOx (16.6X)
0.3 g/kWh PM * 0.2769 kWh/mile = 0.083 g/mile vs T2B5 0.01 g/mile NMOG+NOx (8.3X)

 

[turbobrick240]

Charging a tesla or any EV from a diesel genset is clearly far from ideal. It's also got to be pretty uncommon. I can understand how a diesel genset operating at peak thermal efficiency can be more energy efficient at charging an EV than an ICE vehicle operating well below its engines peak thermal efficiency the vast majority of the time. I have a feeling that most Tesla owners in Oz also have a petrol vehicle or two for longer trips and such.

 

[dremd]

Unless you live in an area where power outages can last for days. If all you have is your ev, then you’ll have to charge by generator.

With what frequency? I've had one day (in 2 years) that charging by generator almost happened, but the power came back on day 3, and I could have driven another vehicle anyways.

If grid power is that unreliable in your location then I'd consider some solar and batteries to save on liquid fuel.

 

[El Dobro]

I've used my Volt for a genset.

 

[oilhammer]

I've used my Volt for a genset.

My '97 Passat TDI ran at high idle in my sister's driveway for THREE DAYS one time when her power went out due to a massive storm.

I just used VCDS to crank the idle speed up to around 1400 RPMs, had an inverter hooked to the battery with the hood propped up. Never missed a beat, ran non stop the whole time. Left a little black soot print in their driveway under the tailpipes.

Funny story about electricity:

When I finally got to bring my son home from the hospital after 18 months, the gal that was helping us get transitioned into home care for him gave my wife a tip. When my wife asked how long the battery lasted in his feed pump (he had a G-J button) as well as his Broviak pump, since the power would frequently go out at our house, she was told to call the electric company and tell them to put us on a priority list. Never heard of such a thing, never knew it existed. But, my wife did call, and there is such a thing, and we had to get some letter from a doctor or whatever as "proof" of a medical condition in which electricity was a priority.

The very next week, no kidding, there were about 20 trucks from the electric company doing a bunch of work near our house at a substation, a bunch of new poles were put in within a mile of my house (not down my road in particular), and since then, our power has been out a total of once. And that was several years ago. Used to go out once or twice a month, and during stormy weather it was ALWAYS going in and out.

Do not know if it was coincidence, do not know if our call put stuff that was slated to be updated on a fast track and got bumped to the top of the list, but something changed.

 

[El Dobro]

That's pretty darn good what they did to help with your son's conditions. My brother was on home dialysis and since the electricity was bad in his area, he wound up having a Generac back-up generator installed.

I'm in a somewhat urban area, so the Volt works out when necessary. Like the Prius PiP I used when Sandy hit us, the ICE turns on to charge the battery, then shuts down. The funny part was the neighbors watching me, trying to figure out what I was doing with the car.

 

[CraziFuzzy]

Let's get down to the crux of comparing emissions OTHER THAN CO2 between a genset and a car.

A Tier-4 large genset of >560 kW (which may be fuelled not only with Diesel but also natural gas, etc.), is permitted 0.19 g/kWh NMHC (non-methane hydrocarbons), 0.67 g/kWh NOx and 0.03 g/kWh PM.
Source: Table 4, https://dieselnet.com/standards/us/nonroad.php#tier4

A T2B5 car is permitted 0.075 g/mile NMOG (non-methane organic gases * for diesel fueled vehicle, NMOG (non-methane organic gases) means NMHC (non-methane hydrocarbons), 0.05 g/mile NOx and 0.01 g/mile PM.
Source: Table 2, https://dieselnet.com/standards/us/ld_t2.php#bins

How do we convert kWh to miles? Normally, it is impossible to convert the two, but we have a clue that the Tesla used 18 kWh to cover 104.6 km / 65 miles. It is reasonable to assume that 18 kW is the energy to propel the 2.2 ton Tesla over the road course, not taking into account round-trip energy losses through the battery and power electronics, as well as any recovered from regenerative braking. So, it would not be unreasonable to apply the same 18 kWh to the ICE-powered car over the same road course.

Thus, 18 kWh over 65 miles gives 0.2769 kWh/mile.

Now, if we go back to the emissions limits above, we apply this factor to the genset:
0.19 g/kWh NMHC * 0.2769 kWh/mile = 0.0526 g/mile
0.67 g/kWh NOx * 0.2769 kWh/mile = 0.1855 g/mile
0.03 g/kWh PM * 0.2769 kWh/mile = 0.0083 g/mile.

Compare these again to that of the T2B5 car:
0.075 g/mile NMOG
0.05 g/mile NOx
0.01 g/mile PM.

I purposely chose to present the genset case in the most favourable light possible so that I would not be accused of bias; the latest standard and the largest size (giving the lowest per kWh values). If I were to do the same on a genset of the actual size in the video (30 kVA =~ 30 kWe) and estimated age, the results would show that the genset is in fact over an order of magnitude dirtier in HC+NOx and nearly an order of magnitude dirtier in PM!!!

Edit to add 30 kWeTier-4 (2008) genset emission data:
7.5 g/kWh NMHC+NOx * 0.2769 kWh/mile = 2.077 g/mile vs T2B5 0.125 g/mile NMOG+NOx (16.6X)
0.3 g/kWh PM * 0.2769 kWh/mile = 0.083 g/mile vs T2B5 0.01 g/mile NMOG+NOx (8.3X)

And that is based on a engine designed to high portability and reliability in that genset, NOT emissions or efficiency. Compare that power generation to a modern natural gas power plant, even with grid losses, and the EV gets a LOT cleaner.

 

[TDIMeister]

And that is based on a engine designed to high portability and reliability in that genset, NOT emissions or efficiency. Compare that power generation to a modern natural gas power plant, even with grid losses, and the EV gets a LOT cleaner.

Wxman will be able to give grid-averaged emissions in g/kWh from Argonne's GREET model and EPA's eGRID so that we can do a quantitative comparison rather than unsubstantiated anecdotes.

I'm looking at 2012 data but maybe more recent data is more available to fairly capture the rise in natural gas-fired plants and renewables in the mix.

Edit: Here - http://forums.tdiclub.com/showpost.php?p=5375529&postcount=94
Great post there by wxman!

 

[turbobrick240]

This is a good article describing some of the complexities when assessing EV manufacturing related emissions:

http://www.greencarcongress.com/2018/02/20180212-icct.html

 

[wxman]

Based on the latest version of the GREET model (GREET_2017), and using the most recent EIA data for U.S. electricity generation mix, the well-to-pump efficiency of electricity is 46.1%. 1,171,169 BTU are required to generated 1,000,000 BTU of electricity at the electric outlet.

ULSD is 81.6% efficient (226,155 BTU to produce 1,000,000 BTU of product to the fuel pump). E10 gasoline is 76.9% efficient (299,811 BTU to produce 1,000,000 BTU of product).

 

[TDIMeister]

Arithmetic error, Loren. You need that many BTU over and above that generated, otherwise the efficiencies will be over unity.

Thus,
2,171,169 BTU per 1,000,000 BTU electricity
1,226,155 BTU per 1,000,000 BTU ULSD
1,299,811 BTU per 1,000,000 BTU E10.

 

[turbobrick240]

Looks like Tesla is cleaning up in the luxury auto segment across Europe. Probably some anxious execs. in Stuttgart and Wolfsburg these days.

https://www.google.com/amp/s/jalopnik.com/the-tesla-model-s-outsold-the-germans-in-their-home-cou-1823163274/amp

https://www.google.com/amp/s/electrek.co/2018/02/20/tesla-dominates-luxury-segment-europe-gas-powered-german-cars/amp/

 

[German_1er_diesel]

Looks like Tesla is cleaning up in the luxury auto segment across Europe. Probably some anxious execs. in Stuttgart and Wolfsburg these days.

I don't understand that Jalopnik article claiming that Tesla's Model S outsold the S-Class and 7-series in Germany in 2017.

It didn't.

Actual 2017 new car registration numbers, straight from the KBA:

Tesla Model S: 2,241

Audi A8: 3,966

BMW 7-series: 4,594

Mercedes S-Class: 6,759

...and if you want to compare with cars based on passenger space, not price tag, BMW sold 42,850 5-series and Mercedes 47,845 E-Class.

 

[wxman]

Arithmetic error, Loren. You need that many BTU over and above that generated, otherwise the efficiencies will be over unity.

Thus,
2,171,169 BTU per 1,000,000 BTU electricity
1,226,155 BTU per 1,000,000 BTU ULSD
1,299,811 BTU per 1,000,000 BTU E10.

You're right, David. GREET doesn't include the BTU value of the fuel itself apparently.

Edit: The efficiencies are given as a separate entity in the "Well-to-Pump" output file. The actual energy consumed in producing the fuel/electricity is provided and is over and above the mmBTU of the fuel itself, which needs to be considered in the actual efficiencies. The output file is labeled "Well-to-Pump Energy Consumption, Water Consumption and Emissions: Btu or Gallon or g per mmBtu of Fuel Available at Fuel Station Pumps" in GREET.

Does that make sense?

 

[turbobrick240]

I don't understand that Jalopnik article claiming that Tesla's Model S outsold the S-Class and 7-series in Germany in 2017.
It didn't.
Actual 2017 new car registration numbers, straight from the KBA:
Tesla Model S: 2,241
Audi A8: 3,966
BMW 7-series: 4,594
Mercedes S-Class: 6,759
...and if you want to compare with cars based on passenger space, not price tag, BMW sold 42,850 5-series and Mercedes 47,845 E-Class.

Yeah, I think that was an error. He should have said the model S outsold the 7 series and S-class in Europe, not Germany specifically. Jalopnik writers tend to be pretty sloppy.

I do think comparisons based on price are most appropriate. People buy $100k cars for the prestige as much as anything. The Germans need to stop giving lip service to EV's and start actually producing decent ones in numbers if they don't want to get steam rolled. It's kind of ironic that the most desired luxury cars in Europe are made in America now.

https://carbuzz.com/news/tesla-destroys-mercedes-and-bmw-in-their-own-back-yard