On biodiesel vs. straight veggie oil

17 Aug 2005

Got questions about the environment? Ask Umbra.

Dear Umbra,

I have the opportunity to convert a 1979 non-turbo Mercedes into a non-diesel. The question I have is: to which should I switch, biodiesel or vegetable oil? I can't seem to find out which one is best, just that these two are better than any petroleum-based fuels, which we already know (thanks for your earlier column on hybrids vs. veggie oil). Also, is it possible to switch from biodiesel to veggie oil, or vice versa, once a conversion is made?

Margaret
Cincinnati, Ohio

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Dearest Margaret,

I've noticed a lot of confusion about the distinction between straight veggie oil (SVO) and biodiesel (BD), so I'm happy to continue recapping.

It's so easy, even a fuel can do it.

Here's the lowdown: No conversion is necessary to run your diesel Mercedes (or Peugeot or VW or Ford) on biodiesel. As I've mentioned before, biodiesel has been chemically altered to behave almost exactly like petrodiesel, and it can go straight from pump to tank. (Learn more from friendly Rob, this week's InterActivist.)

But veggie oil is different. Although you can put SVO directly into your diesel tank, it's not generally recommended. SVO conversion kits essentially add a second fuel tank, and your old tank remains a necessary part of the action. To address your second question, then: switching back and forth is simple if you do this conversion, since you could fill your regular tank with BD.

Which you should choose for your primary fuel is mostly related to your financial and time constraints. If BD pumps are available where you live, you'll pay market rates, which -- according to the government's latest alternative-fuel price report -- were hovering just under $2.50 per gallon this spring. (Lately, my faithful readers have been reporting prices closer to $3.50.) Eventually you may need to replace some hoses, but other than that it'll be exactly like using petrodiesel. Converting to SVO, on the other hand, involves the price of the kit and the cost of installation; it's an endeavor that could run you as much as $2,500.

The ongoing hassle of SVO is obtaining and preparing the oil, and repairing the conversion kit if it malfunctions. Instead of stopping at the BD pump, you'll need to plan in advance to obtain, perhaps heat, and definitely filter and store your oil. So although waste oil often involves no cash, it does involve time. Thus far, SVO loses to BD on the hassle front. But to look at it from another perspective, using SVO is much less hassle than making your own biodiesel -- a daunting task.

In a way, it depends on your goals. Do you want free and/or dirt-cheap fuel? Go with SVO or make your own BD. Are you attracted to home chemistry projects and excited to transesterify fatty acids? Definitely make your own. Do you want to reduce your emissions but change nothing else about your car habits? Go with BD at the pump. Is there no fueling station near you? See if you can form a biodiesel co-op with friends and neighbors. And happy motoring.

Measuredly,
Umbra

Yours is to wonder why, hers is to answer (or try). Please send Umbra any nagging question pertaining to the environment -- but first check out her FAQs!

The claims made in this column may not reflect the views of this magazine. Neither the magazine nor the author guarantees that any advice contained in this column is wise or safe. Please use this column at your own risk.

Umbra Fisk is Grist Research Associate II, Hardcover and Periodicals Unit, floors 2B-4B.

Comments: (3 comments)

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It's easy

Howdy,

As 'one of those people' who has actually done what everyone else has been talking about doing, I'll tell you that converting to WVO is a piece of cake if you are even moderately intelligent.
Before converting my car I had only ever changed oil. And the whole thing only cost me $600.
Sure, making biodiesel is a hassle, but compared with the labor you put into making the money to buy diesel or biodiesel, it's well worth it. They way i have it figured, even if you paid someone $10 hour to make your biodiesel, you'd still be paying less that $2 gallon.
My website htp://www.veggie-fuel.org has tons of links to help DIYers convert their cars and make their own biodiesel processors.
(note: while I do solicit installation of biodiesel processors on my site, Dreamer Propulsion is a non-profit, and our main focus is the open sharing of information on WVO and biodiesel. I love talking about this and answering questions and gladly do so for free.)

by Kalanu at 2:16 PM on 17 Aug 2005

biodeisel vs. straight veggie oil

Good, balanced article.... I have been interested in doing a conversion for some time, and found an answer to hassle free conversion to straight vegetable oil... two very environmentally committed, and enthusiastic young guys, one a product designer, the other a deisel mechanic, have combined forces and have developed a very high quality conversion system...check it out at www.vegpower.com there is no doubt that their hard work has resulted in top quality components and a few innovations to boot. Drive to Ithaca NY and have your deisel converted, or simply order their system and do it yourself (with the help of a local mechanic)...

by mainemountainguy at 4:23 AM on 18 Aug 2005

Yep Umbra!

Good advice, a biodiesel cooperative in someone's garage is the way to go. Even if it's only extended family size. I have seen it work here!

What I really like though is a plugin electric car with a biodiesel powered generator as a backup. The beauty of this is that a wind or solar system can charge your car for regular commutes, then the biodiesel can power longer trips.

The amount of biodiesel used then would tend to match the waste vegetable oil resource.

Anti biodieselers generally point out (rightly so) that the only green source of biodiesel is recycled cooking oil (agri-chem farming is far from green, dependent upon oil)and that this source can only provide a small fraction of fuel needs.

Well no problem then, reduce fuel needs to match waste veggie oil supply by mainly using wind and solar electric power for most driving.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 8:30 AM on 18 Aug 2005

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On biodiesel vs. straight veggie oil