Exaust Emissions in BioDiesel Jetta vrs Prius

[hdrygas]

I was heaving a very nice discussion with a Jetta owner who is running Bio Diesel about exhaust emissions. She stated that my Prius produces more particulates that her diesel. She is running straight Bio Diesel no cutting with Petrol Diesel. That did not seem right. She also said that I produced more Sulfur and I would guess that is right. Clearly as long as there is enough biomass on the planet she is carbon neutral. Can any one help me out here? Point me to a site that can be trusted? I hate to use data from a site extolling the virtue of Bio Diesel and would like an independent observer. What do you all think?

[kidtwist]

I found this link: Bio Diesel vs Hybrid (Grist Magazine). I don't know much about this stuff, so I can't promise it's accurate.

[MGBGT]

I've always been interested in this question as well, but don't know enough about the matter to be able to contribute.
Based on my limited understanding, I would guess that the Prius is better than a 'fossil fuel' diesel any day. Biodiesel however has the advantage that the living plants from which it is made, use up carbon dioxide during their life, and most estimates suggest that they use up an amount comparable to the carbon dioxide that is released when burning biodiesel, so running biodiesel would appear to be 'sustainable'. However, this does not take into account (AFAIK) the cost and energy to collect and process biodiesel, but honestly I don't know.
Particulate matter and sulphur: I think (but may be wrong) that particulate matter in diesel exhaust comes largely from dirty diesel and sulphur content. It makes sense that fossil fuesl have these, but biodiesel would not unless sulphur is introduced in the process of making it palatable to cars. It therefore seems convincing that biodiesel engines produce little particulate matter and less sulphur than the Prius.
Overall, I think it's hard to argue that a Prius would be better than a biodiesel car. Hhhhmmm, maybe my next car will be a biodiesel?
Maybe the best car would be a hybrid that uses a biodiesel ICE?

[Tadashi]

Either it was just me or that article was confusing. I still do not think that article answered the question of which one produces more emmissions.

Their closed carbon cycle does not make sense to me. If you think about it even gasoline were once creatures (plants and animals) that consumed carbon but took millions of years to reach the state of becoming oil. http://www.astronomycafe.net/qadir/q1161.html

To me the only way to check would be to hook up a SVO diesel to an emmissions tester and read the results. The only thing I like about it is that it would help reduce the dependence on foreign oil but not reduce emmissions (compared to the Prius). Now a hybrid diesel using SVO would probably be optimal for an environmentalist.

From http://www.biodiesel.org/resources/faqs/
How do biodiesel emissions compare to petroleum diesel?
Biodiesel is the only alternative fuel to have fully completed the health effects testing requirements of the Clean Air Act. The use of biodiesel in a conventional diesel engine results in substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter compared to emissions from diesel fuel. In addition, the exhaust emissions of sulfur oxides and sulfates (major components of acid rain) from biodiesel are essentially eliminated compared to diesel.

Of the major exhaust pollutants, both unburned hydrocarbons and nitrogen oxides are ozone or smog forming precursors. The use of biodiesel results in a substantial reduction of unburned hydrocarbons. Emissions of nitrogen oxides are either slightly reduced or slightly increased depending on the duty cycle of the engine and testing methods used. Based on engine testing, using the most stringent emissions testing protocols
required by EPA for certification of fuels or fuel additives in the US, the overall ozone forming potential of the speciated hydrocarbon emissions from biodiesel was nearly 50 percent less than that measured for diesel fuel.

http://www.worldenergy.net/product/emissions.asp
http://www.soypower.net/BiodieselPDF/Biodi...elEmissions.pdf
I could not find any analysis that I could use to compare the Prius to the SVO.

[t'rants]

If you think about it even gasoline were once creatures (plants and animals) that consumed carbon but took millions of years to reach the state of becoming oil.

Yes, but generally speaking it's the plants that fix atmospheric carbon, not the animals, and research suggests a much higher percentage of CO2 in the atmosphere at that time in the planet's history; the idea being that to preserve present climatological conditions we want the CO2 that was long ago fixed by those plants to stay fixed and in or below the earth's crust.

[john1701a]

Biodiesel is quite amusing. I've burned quite a number of diesel supporters by pointing out that it actually *INCREASES* the level of NOx emissions (a major contributor to smog).

No person with honest intentions would ever compare biodiesel to gas. That just plain is not fair. It should be biodiesel to biogas (ethanol).

By the way, unlike biodiesel, ethanol actually reduces NOx. That's why E10 (10% ethanol, 90% gas) has been standard in Minnesota for years now and E20 will be starting in 2013.

[Godiva]

Here's epa.gov

http://www.epa.gov/otaq/models/biodsl.htm

I think to be truly fair you have to compare all aspects, no just emissions or mileage but also production and maintenance across the board:
gas, biogas, diesel, biodiesel and electric.

And the all important component of how much pollution it takes to produce these fuels in the first place. If you're burning coal to produce electricity.....it's not all that great a tradeoff.

[john1701a]

It's really hard to get some to look at the big picture.

And the reality of living in the rust-belt adds an interesting twist to "across the board" measurements too. Yes, it may last +200,000 miles on paper. But on roads covered with salt & sand and exposed to both extreme humid-heat and extreme dry-cold, the vehicle body falls apart before the diesel or hybrid system will.

[hdrygas]

I have now spent about 3 hours trying to get accurate data on the real world use or even lab data on the two cars as powered and I have ended up nowhere so far. The data is general not specific. As near as I can tell so far no one looked into this. What are the emission data for a Jetta using Biodiesel? So far I can not tell. Data on an unnamed diesel engine does not cut it. While I don't doubt improvements I ask how much? Well back to work! :mrgreen:

[Sufferin' Prius Envy]

Yes, but I think the addition of C27H45OH to the emissions cocktail as a result of using BioDiesel is being scandalously swept under the rug in the name of environmental correctness!

Isn’t cholesterol considered an environmental hazard?

If not, then maybe they need to do studies on the physiological affects of atmospheric cholesterol and on the psychological affects of the smell of BioDiesel.

Smelling Rendering Plant BioDiesel exhaust could be the straw that causes someone on the edge to commit murder!

French Fry BioDiesel smell could cause someone with a weak impulse suppression to eat themselves to death.

I can just see the headlines and late night infomercials. “Have you been the victim of BioDiesel exhaust? Call the law firm of BOGUS AND BOGUS and join our Class Action lawsuit today!”

[ :P , ]