Intellichoice: Hybrids Save Money After All

Two comments:

Almost all of their savings were from reduced depreciation, and I believe they grossly overstate that, at least for older Prii, based on my look at recent used car prices in the Washington Post and the Kelly Blue Book values. I posted those in another recent thread. As far as I could tell, a high-milage Prius holds its value about as well as any high-mileage Toyota.

Second, as a former diesel owner, from now on, every time I see a "diesels can get great mileage" plug, I'm going to call that largely an illusion. Diesels largely get better mileage because there is more hydrocarbon in a gallon of diesel than a gallon of gas. So, as I understand it, it takes about 25% more oil to make a gallon of diesel than a gallon of gas, and a) a gallon of diesel weighs about that much more than a gallon of gas, contains roughly that much more energy than a gallon of gas, and contains about that much more carbon than a gallon of gas. And, these days, costs about that much more than a gallon of gas (though that is clearly subject to supply/demand considerations for gas, diesel, and heating oil.)

In other words, it's not very smart to compare diesel and gas in terms of gallons of fuel used. There's "more" in a gallon of diesel whether you measure it by a) crude oil used, B) carbon produced in burning, or c) cost.

To buy a diesel because it gets more miles per gallon of diesel fuel, than a gas car gets per gallon of gasoline, as I once did, is just not very smart. I have repented, now I'm out to inform the world.

If the question is "which vehicle consumes the least crude oil per mile" or "produces the least C02 per mile" or "has lowest fuel cost per mile", then the rule of thumb that I read is that you should multply diesel mileage by 0.8 and compare that to gas mileage.

To put this in perspective, under this rule, a 50 MPG Prius is equivalent to a 62 MPG diesel.

 

Thanks for the input on diesel, Chogan.

I have a friend who has a small VW diesel. When I told her abou tmy Prius and the mileage I get, she said, "Big deal! I get that in my diesel already."

I told her that the Prius emmisions were much lower. That seemed to shut her up temporarily, but it is great to have more ammo.

 

<div class='quotetop'>QUOTE(MechaJohn @ Jan 19 2007, 12:37 PM) [snapback]377762[/snapback]</div>

And yours (the car) is bigger.

 

<div class='quotetop'>QUOTE(chogan @ Jan 19 2007, 05:26 AM) [snapback]377655[/snapback]</div>

It's not 25% more. It's 100% more. I posted about this before at http://priuschat.com/index.php?showtopic=2...mp;#entry276398. Unfortunately, the API PDF is gone but there's another reference to this at http://en.allexperts.com/q/Energy-Industry...il-refining.htm. Anyone here still have a copy of that PDF?

I wish there were some petroleum engineers here as I'm not totally clear if these proportions are purely from fractional distillation without using cracking (to convert from one form to another) or if these are final outcomes driven by demand.

edit: I found the new location for the PDF. It's at http://www.api.org/classroom/tools/upload/oilfacts_rgb.pdf.

 

First of all, this being my first post: and a very big thank you to everyone who makes PC such a wonderful community resource.

<div class='quotetop'>QUOTE(cwerdna @ Jan 19 2007, 09:47 PM) [snapback]378159[/snapback]</div>

In either case, it's not that a barrel of crude can make either 19.4 gallons of gasoline or 10.5 gallons of distillate (mainly diesel+heating oil). Rather, among the distillation products of a barrel of crude, on an average, there's 19.4 gallons of one and 10.5 gallons of the other. I'm not sure how to divide out, say, the energy spent in the refinement, over the gasoline and diesel parts (in order to compare their well-to-pump impact); but I don't think that "it costs twice as much energy to extract diesel than gasoline" is a valid conclusion.

 

<div class='quotetop'>QUOTE(rajH @ Jan 20 2007, 03:33 AM) [snapback]378204[/snapback]</div>

I should've stated my original point more clearly as you have for me. A barrel of crude produces many resulting products including both gasoline and diesel but approximately 2x the amount of gasoline as it does diesel.

I never stated or concluded "it costs twice as much energy to extract diesel than gasoline".

 

<div class='quotetop'>QUOTE(chogan @ Jan 19 2007, 05:26 AM) [snapback]377655[/snapback]</div>

Simply on a "CO2 per mile basis", the multiplication factor should be 0.87, given that diesel has about 2778 grams of carbon per gallon while gasoline has about 2421 (according to the EPA).

Comparison on the other two metrics would be much more difficult (at least, I know precious little about it). If anyone can suggest any good references for well-to-pump comparisons of fuels, I'd appreciate it very much. Thanks,

Rajneesh.

 

<div class='quotetop'>QUOTE(chogan @ Jan 19 2007, 08:26 AM) [snapback]377655[/snapback]</div>

BUT, there is no partial zero emission vehicle "diesel" to my knowledge. No matter how clean they are becomming.

 

<div class='quotetop'>QUOTE(Rangerdavid @ Jan 20 2007, 08:26 AM) [snapback]378211[/snapback]</div>

Exactly. Just saying the new diesels are as clean as a regular gasoline vehicle is NOT good enough. Every year we have some bad air quality days here in Raleigh. It's not going to get better if we continue the way we're going.

 

<div class='quotetop'>QUOTE(rajH @ Jan 20 2007, 06:44 AM) [snapback]378206[/snapback]</div>

EDIT: I rewrote this post in light of more data sources.

Well, I hate to say this but my earlier post on diesels may have been misleading. Not wrong on the facts -- more oil, more calories, more weight, more carbon. And after study, I conclude that the simple MPG comparison between diesel and gas DOES overstate the overall wheel-to-well energy comparison. It's just that it's not as simple as the oil inputs alone.

Here are several wheel-to-well comparisons. My summary is at the bottom of the post.

Here's a seemingly serious European study of wheel-to-well efficiency that says diesels have slightly lower total energy requirements per mile and lower GHG emissions per mile, cpmpared to straight-gas technology. So, the oil input is not the entire story. See the graph, P 23, in the PDF document here:
http://ies.jrc.cec.eu.int/media/scripts/ge...port_030506.pdf

which is on this website:
http://ies.jrc.cec.eu.int/wtw.html

That graph shows both conventional 2002 gas and diesel, and projected 2010 gas and diesel hybrids. In both instances, diesels outperform by a small margin (looks like about 5% to me). Gas hybrids outperform conventional diesels by a large margin.


Here's a DOE study comparing liquid fuel vehicles and they too give diesels modestly better "equivalent" mileage than gas cars, but give gas hybrids better "equivalent" mileage than traditional diesels. Oddly, they give fuel cell vehicles vastly better equivalent mileage -- not sure how they got there. And of course they did not consider EVs at all. The key pages are 12 and 13.

http://www.transportation.anl.gov/pdfs/HV/300.pdf

GM says diesel hybrids and hydrogen fuel outperform all others, including EVs. Guess it must be so if GM says it:
http://www.gm.com/company/careers/career_p...l_to_wheel.html

Toyota says of all options currently available, gas hybrid (Prius) has the best performance.
http://www.toyota.com/about/environment/te...ll-To-Wheel.pdf

Toyota's doc has the advantage of being clear and readble. They show a slight advantage of diesel over straight gas, significant advantage of hybrid gas over diesel, and show nowhere near the advantrage of hydrogen that the DOE and GM show.

Well, that's enough to convince me that, for equivalent vehicles, for wheel-to-well efficiency, these are the consistent statements::
a) diesel beats straight gas technology, by a small margin.

b) hybrid gas beats diesel -- all sources that I looked at, from which that could be determined, said that. By a large margin.

c) a hypothetical hybrid diesel would beat hybrid gas, by a small margin.

d) there's a whole lot of wiggle room in how wheel-to-well efficiencies are calculate for the rest of them.

Please note that this pretty much excludes EVs.

Based on the numbers, I believe my original statement was essentially correct -- for the same vehicle, the difference between diesel mileage and gas mileage overstates the actual wheel-to-well efficiency of the diesel relative to gas. You need to knock the diesel milege down some.

I believe that all the sources show that diesels are slightly more efficient -- on the order of 5% -- compared to straight gas technology, wheel-to-well. Only the European paper (first cite) also says they have 5% lower GHG emissions, compared to straight gas technology.

Clear, since gas hybid is so much more efficient than straight gas, it is substantially more efficient that straight diesel.

I don't claim to have settled the environmental impact side of this. The european study suggests that diesels are in total producing slightly lower GHGs per mile, basically proportional to the better energy efficiency. But that's not the same as measuring the level of noxious pollutants emitted where people have to breathe them.

 

When I was shopping for a new car, this is all I needed to know to make my decision (of course, fuel prices were quite a bit higher than but the relative costs seemed to be the same):

Jetta TDI

Cost to Drive 25 Miles $1.62
Fuel to Drive 25 Miles 0.66 gal
Cost of a Fill-up $32.10
Miles on a Tank 496 miles
Tank Size 14.5 gal
Annual Fuel Cost* $970
* Based on 15000 annual miles and a fuel price of $ 2.46 per gallon

Camry hybrid

Cost to Drive 25 Miles $1.43
Fuel to Drive 25 Miles 0.64 gal
Cost of a Fill-up $34.52
Miles on a Tank 604 miles
Tank Size 17.2 gal
Annual Fuel Cost* $856
* Based on 15000 annual miles and a fuel price of $ 2.23 per gallon

Prius
Cost to Drive 25 Miles $1.01
Fuel to Drive 25 Miles 0.45 gal
Cost of a Fill-up $23.88
Miles on a Tank 589 miles
Tank Size 11.9 gal
Annual Fuel Cost* $609
* Based on 15000 annual miles and a fuel price of $ 2.23 per gallon.

http://www.fueleconomy.gov/feg/findacar.htm

I ended up getting the Camry hybrid. I don't know why Jetta owners try comparing the Jetta TDI to the Prius--even the Camry hybrid has it beat from a $ per mile perspective. Additionally, I'd heard so many maintenance horror stories regarding VW. I thought it was ironic that cars using relatively new technology were more reliable than cars using relatively old technology.

 

ummm when diesel drivers "say" they are getting comparable mileage, have them track 3 fillups. i had my old neighbor who got a diesel VW jetta less than a month after i got my 04 Prius. she claimed the same thing.

well, it didnt take three tanks for her to realize she was getting way worse mileage than me. we had similar commutes (short, mostly in town with only occasion freeway driving) and she was only getting 38 mpg to my 56 mpg in the summer.

but she also had her car in the shop three times in the first 6 months. her car cost her $2,000 more than mine did (i only had a pkg #1)

although she thought my car looked funny, it had WAY more space, she ALMOST admitted that she might have made a mistake but made this admission before knowing about the 3-4 month wait for a Prius at that time

 

I go by my wallet. Right now I commute an average of 2000 miles a month. I have a big crew cab Silverado that gets barely 20 MPG on a good day that I used before I bought the Prius. Granted I picked up an extra car... the fuel cost savings alone "makes" the Prius car payment.

The price of the Prius was of debate for I could have bought 2 Corollas for the same price, but when you average out the fuel costs and plus I wanted to play with the new technology. It was a wise choice.

I actually owned a 2002 VW Jetta TDI for two years. It ran great for the first year and I averaged 40 miles to the gallon. But year 2 it spent most of it's life in the shop. Almost every electronic component failed. The dealer had the "nerve" to say we were driving the car wrong!

The Jetta was OK when it ran. It was hard sometimes to find diesel when I got away from my known paths. A GPS Nav unit would have helped back then.

Yet overall I have been more impressed by the Prius with its ability to get around 50 mpg and use any gas station.

I agree with DaveinOlyWA the Prius has the Jetta beat space wise and rear passenger comfort. My dad the ultimate critic rode in back of the Prius the other day... and was surprised by the room. Although he did keep complaining about the MFD showing the wheels truning. He said that was a stupid gimmick.

Oh, well, 4 months of owner ship I've been averaging 50 mpg! That saved me close to 220 gallons of gas compared to my Silverado.

 

<div class='quotetop'>QUOTE(Squint @ Jan 21 2007, 08:23 AM) [snapback]378650[/snapback]</div>

Maintenance does not equal reliability. Maintenance is consists of things like oil changes, inspections, fluid changes, etc. as part of upkeep as outlined in the manual. Almost every VW model has below average to very poor reliability and that means you have repairs that need to be done that aren't a part of maintenance.

I've posted about poor VW reliability a bunch of times in the past here like at http://priuschat.com/index.php?s=&show...st&p=239612 and elsewhere at http://www.priusonline.com/viewtopic.php?p=74941#74941.

Although I don't trust JD Power that much (I trust Consumer Reports reliability ratings more), you can see that VW has fared poorly numerous times in their vehicle dependability studies (they aren't long term enough IMHO):
http://www.jdpower.com/corporate/news/rele....asp?ID=2006133
http://www.jdpa.com/news/releases/pressrel....asp?ID=2004055
http://www.jdpa.com/news/releases/pressrel....asp?ID=2003050
http://www.jdpa.com/news/releases/pressrel....asp?ID=2002141
http://www.jdpa.com/news/releases/pressrelease.asp?ID=2074

 

I guess I’ll ask the inverse of the question that I just asked on the TDIClub. Why the need for PriusChat members to bash diesels? Why the thinking that Hybrid=Good / Diesel=Bad? Both technologies decrease fuel consumption which decreases our dependence on fossil fuels. In my mind, a diesel series PHEV would be the best of both worlds.

The 07 Prius is a Tier2 Bin3 vehicle. The 2007 Mercedes diesels are Tier2 Bin 10. With the arrival of ultra low sulfur diesel fuel, the 2008’s will be Tier2 Bin 5. The whole Prius PZEV thing is just politics. The Prius is never a zero emission vehicle. Even when running on batteries, it is using energy created by gasoline. Until we have a plug in option, the PZEV classification will only be political label.

As you might suspect, I own a diesel vehicle as well as my Prius. It is a ’03 VW Jetta TDI Wagon with 140,000 trouble free miles. It is about the same size as the Prius. (The Prius has more rear leg room, the TDI has more luggage capacity.) The TDI also is a whole lot more fun to drive and has a much better quality interior. The only none scheduled maintenance I have done was to replace the glow plugs last week. However, a lot of people I know have had electrical problems with the Jetta Sedans and New Beetles built at the Mexican plant. Over the life of the vehicle I have averaged 49 mpg. The best tank was 56mpg and the worst was 44 mpg. BTW, that mileage is with sticky performance tires.

Biodiesel is an excellent option and is carbon neutral. The reason VW of America only warranties use of B5 is because the US doesn’t have a standard for biodiesel. Until, we set a regulatory standard, no OEM will warranty the use of biodiesel because there is no guarantee of fuel quality. Right now you don’t know if the biodiesel you pump into your car was made by Shell or some guy in his barn. It doesn’t mean that biodiesel won’t work. In the EU, they have a standardized biodiesel and the OEM’s do warranty the use of biodiesel. I’ve seen B100 at quite a few fuel stations in Europe. VW is currently pushing the US government to set biodiesel standards, so that they can allow for use of biodiesel in North America.

 

<div class='quotetop'>QUOTE(jhinton @ Jan 23 2007, 11:58 AM) [snapback]379654[/snapback]</div>

Decreasing refined fuel consumption does not necessarily equal decreasing dependence on fossil fuel as I pointed out above. Maybe I should drop the API an email asking the question. I've sent the question to some car magazines hoping they'll research it and give an answer.

Before you go griping about "PZEV" being politics, take a look at http://www.epa.gov/greenvehicles/about.htm and the table at http://www.epa.gov/greenvehicles/detailedchart.pdf for the limits allowed for each classification. Tier 2 Bin 10 and 5 are both TERRIBLE compared to the Tier 2 Bin 3 that most Priuses have and the SULEV II/PZEV rating that Cali and NE state Priuses have. http://www.driveclean.ca.gov/en/gv/faq/index.asp#2 also defines "PZEV"

As for reliability, as I've mentioned in other posts (maybe on other boards), my guess is that VWs must have VERY inconsistent quality. There are some, like you who claim to have had little or no trouble w/their VWs. Others have problems and are in denial claiming that VWs ARE reliable. Then there a whole bunch who have LOTS of problems w/their VWs. It seems the population of the ones w/lots of probs is equal to or greater in size than those who have no probs.... I've NEVER observed such a large proportion of the last group w/Honda and Toyota owners.

 

<div class='quotetop'>QUOTE(jhinton @ Jan 23 2007, 02:58 PM) [snapback]379654[/snapback]</div>

For my part, I was not bashing diesels. I just want people to make rational choices with full information. If a person chooses a nominal 50 MPG diesel over a nominal 48 MPG gas hybrid because they think they are reducing US energy consumption more by making that choice then they have chosen in error. The nominal difference in vehicle MPG does not reflect the actual wheel-to-well efficiency. That's all I wanted to say. Based on the wheel-to-well studies above, a 49 MPG diesel is about as efficient, overall, as a 40 MPG gas car.

 

Emissions: I have been to the EPA’s website and I’m quite familiar with the file you posted. Here is a quick summary for those that don’t want to sort through all the pages:

----------------------NOx----NMOG----CO------PM------HCHO
SULEV II--------- 0.02-----0.010------1.0------0.01------0.004
T2Bin3-------------0.03-----0.056------2.1------0.01------0.004
T2Bin5-------------0.07-----0.090------4.2------0.01------0.018
T2Bin10a----------0.60-----0.156------4.2------0.08------0.018
T1LDV (Gas)-----0.60-----0.310------4.2------0.10------None
T1LDV (Diesel)--1.25-----0.310------4.2------0.10------None

Glossary:
PZEVs: PZEV have the same standards as SULEV II but manufacturers must guarantee that the PZEV’s meet the standards for a longer vehicle lifetime (15year / 150,000 miles) plus have a fully-sealed, zero-emissions fuel system.
NOx: Oxides of Nitrogen (SMOG)
NMOG: Non-Methane Hydrocarbons (SMOG)
CO: Carbon Monoxide (Poisonous Gas)
PM: Particulate Matter (Carcinogen, Lung Irritant)
HCHO: Formaldehyde (Carcinogen, Lung Irritant)

As you can see from Bin10 to Bin5 NOx drops by an order of magnitude. Yes, it is still higher than Bin 3 and SULEV II but the reduction is amazing. Bin 5 is 85% lower than Bin 10 and 1786% lower than T1LDV Diesel. Progress is being made and will continue to be made. This is the only first generation of diesel vehicles with catalysts. This is also the first time that diesel vehicles have been required to meet the same requirements as gasoline vehicles.

PZEV Label: PZEV was added to CARB classifications after they killed the ZEV mandate. I believe it was put there to confuse the public. So a Prius doesn’t emit emissions from its fuel system, but it still pollutes every time that it moves. EV’s can be truly ZEV if they are charged using wind / solar / or hydro. I'm also disappointed that PZEV are exempt from smog checks in some states.

Fuel Price: Diesel fuel is currently more expensive than gasoline, but it is a seasonal difference. Diesel is generally more than gas in the winter and less than gas in the summer. From 1996 to 2006, diesel fuel has averaged $0.01 per gallon more than 87 octane gasoline.

Fuel Density: Yes, diesel fuel has more energy per gallons than gasoline. (147,000 BTU / 125,000 BTU) That comes out to 17.6% more energy per gallon. But again, what are you going to do with the heavier elements in crude oil if you don’t make diesel?

I see both hybrid vehicles and diesel vehicle as being a start in the attempt to reduce fossil fuel use. Neither technology will make much of a difference if we continue to drive more miles per year. Yes, hybrids are cleaner than diesels but I believe that very soon, diesels will be just has clean as gasoline cars. That begs the question of the diesel hybrid.

I’m excited about hybrid technology because I see it as a stepping stone to something better. After all, even our beloved Prius is just a gasoline car + electric components. What if an OEM were to completely rethink a vehicle to take full advantage of current technology?

I guess I’m a bit more concerned about the tone of discussion. It seems that there are people in both camps that seem to think that the technology that they have chosen in the “ONE TRUE WAY†and that anyone that may disagree is an idiot. With a foot in both camps I tend to get it from both sides.