On hybrids vs. veggie-oil cars

14 Mar 2005

Got questions about the environment? Ask Umbra.

Dear Umbra,

I currently drive a 2002 Toyota Prius that gets about 40 to 42 miles per gallon on the highway, which is where most of my driving takes place. However, I've recently become enamored with biodiesel vehicles, and specifically with straight vegetable oil (SVO) vehicles. I'm interested in investing in an SVO system fueled by, hopefully, recycled oil from local restaurants.

I've looked into your column archives, and in covering the question of biodiesel versus gasoline, you sided with gasoline. However, you've never grappled with the interesting question of an SVO vehicle versus a hybrid. (As there are no diesel hybrids, this is an either/or dilemma.)

So, great purveyor of ecological truths, cast your wisdom on this quandary. Which is the better environmental choice: to run a straight recycled vegetable-oil diesel engine for long trips, or to run a gasoline hybrid?

Ponderously,

Marc
Minneapolis, Minn.

Ask Umbra continues below

ADVERTISING POLICY

Dearest Marc,

You have stung me to the quick. I did not side with gasoline. I asserted that gasoline is better than diesel, but not better than biodiesel.

Fuel up!

Photo: Biodiesel America

Not only will biodiesel result in lower carbon-dioxide emissions than gasoline; it is also an alternative fuel, and supporting it sends an important message about prioritizing the environment. Hybrid cars deserve our support, but they rely on gasoline, the supply of which is rapidly dwindling and the extraction of which is wrapped up in nasty world politics and pollution.

I'm glad you have a Prius, but I completely support your switch to biodiesel, and also to straight vegetable oil from restaurant fryers. Fellow readers, to briefly review: Gasoline is petroleum-based. Biodiesel is chemically altered (transesterified) vegetable oil or animal tallow. SVO is new or filtered chemically unaltered veggie oil. Diesel engines can theoretically run on any vegetable oil. In an upcoming column, I'll go into how to run your diesel on SVO, but today we will focus on Marc's question: should we bother?

Marc, scientific data with which to evaluate your SVO fantasy are hard to come by -- particularly data comparing SVO to gasoline rather than to diesel. There just aren't the miles driven on pure SVO, or the audience for the technology, to have authoritative information yet. Running your car on SVO requires retrofitting the engine with additional tanks, hoses, and heaters, so a complicating factor for research is the wide variety of diesel cars and the wide variety of conversion methods. Not to mention comparing the burning of McDonald's fryer oil run through a coffee filter against the burning of tempura fry oil filtered to five microns.

But you can feel good knowing that vegetable-oil fuels are "biomass" fuels and are considered to have a "closed carbon cycle." That means that the carbon released during their burning is balanced by the carbon absorbed during their past lives as plants. We can think of the soy and rapeseed that made the oil as the housemaids, cleaning up the mess made by our personal automobile. Phew. In the future, we may get a specific lifecycle analysis of this fuel, but at this point, given the reading I could find, I feel confident encouraging SVO, a non-petroleum, closed-carbon-cycle alternative fuel.

Down at the Environmental Defense Tailpipe Tally, your 2002 Prius, driven 12,500 miles in a year, will produce 4,990 pounds of carbon dioxide, 135 pounds of carbon monoxide, and 9.4 pounds of nitrogen oxides. In the closed-carbon-cycle competition, the Prius is shut out: fossil fuel sequesters carbon for eons and is created equally slowly, so we cannot depend on crude oil to clean up our carbon mess. If the closed cycle is like having a housemaid, the fossil-fuel cycle is like never cleaning and just waiting for the house to decompose. Which, I guess, is what we've been doing since the Industrial Revolution.

Unctuously,
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: (10 comments)

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Not so hot veggie oil

The problem with all commercial biofuels is agriculture. According to Richard Manning, the average calorie of food contains 10 calories of fossil fuel energy. So if we take food (such as soy oil) and burn it in our cars, we ought to divide our MPGs by 10. Not to mention that agriculture is a major source of NOx emissions even without all those fossil fuels. And the only reason soy can compete with gasoline is the massive government subsidies used to grow it. If we reverted to animal or human powered agriculture, the embodied energy would drop, but the horses and people would eat all those surplus calories. A friend of mine at Stanford did his undergraduate thesis comparing the net emissions of biodiesel and gas as auto fuel, and found that biodiesel was much better at the tailpipe, but that it was worse when the full production costs were calculated. Unfortunately, I lost track of said friend, and I don't have a copy of the paper, nor do I know whether he published it.

Of course, recycling restaurant oil is using a waste product, and looks much better, but again, it seems problematic. Do we really want to be dependent on restaurants that serve people really really unhealthy food (i.e. food that is deep fried)? And how much waste restaurant oil is out there? Today, there is plenty for all the hippies and eco-freaks doing veggie oil conversion - but if this catches on I'm sure it won't last long.

I don't mean to suggest we shouldn't try out alternative fuels, but we need to be cautious about these seeming technological magic tricks with biomass fuels. Humans already appropriate a huge percentage of the earths primary productivity, and that is without major investments in biomass energy from the industrialized world. If it seems too good to be true, its probably because it is.

by Forrest at 2:21 PM on 14 Mar 2005

True but..

I think that the "biofuels lifecycle is energy negative" thing hasn't been true for a couple of decades (either production means have changed or the theory has been debunked -- I haven't followed it closely enough).

As for the use of petrochemicals in agriculture, we don't have to use those. In fact, using them along with monoculture results in overall lower yields (except maybe the first few years) than organic polyculture. But the chemical corporations are making way too much money off the business of ruining arable soils to let the people who know better stop them...

I suggest reading the chapter on this subject in David Suzuki's "Good News for a Change" book. The whole thing is excellent and very well documented.

--
SUVs are squared-out minivans.

by MikeCapone at 5:27 PM on 14 Mar 2005

Cellulose

Randomly found this:

"Current research suggests that the best plant-based, short-term alternative to oil is ethanol produced from cellulose. We can make cellulosic ethanol from fast growing crops like switch grass or willow trees, or from agricultural waste like rice hull. Ethanol from cellulose has several advantages over the corn based fuel. It can theoretically cut greenhouse gas pollution by almost 100% and may be much cheaper to produce. Since there are more sources of cellulose, this fuel is less likely to compete for cropland. And it may be possible to produce cellulosic ethanol for less than the cost of gasoline."

http://www.enn.com/today.html?id=7317

--
SUVs are squared-out minivans.

by MikeCapone at 5:52 PM on 14 Mar 2005

Biofuels and agriculture

In his new book Winning the Oil End Game, Amory Lovins describes a technically-feasbile way for ending the need to import oil in 20 years. In the book he shows how 20% of our current imports could be offset with biofuels. He, too, was concerned about the possible competition between (bio)fuel vs. food production and describes a scenario in which all the biofuels are created by lignin/cellulose production, not farm crops. You can download the entire 300 page book and footnotes at www.oilendgame.com.

by DaveBrook at 10:21 AM on 15 Mar 2005
[ Parent ]

Biofuels, Biomass and Agriculture

Dear all,

You might be interested in these three articles regarding biofuels, biomass incineration and agriculture.

George Monbiot column ~
Feeding Cars, Not People: The adoption of biofuels would be a
humanitarian and environmental disaster
http://www.monbiot.com/archives/2004/11/23/feeding-cars-not-people/

Paving the Amazon
Most worrisome to environmentalists is the fact that the interests of agribusiness seem to be trumping any hope of a sustainable future in the Amazon.
http://www.alternet.org/story/21417

Gainesville, Florida is faced with a second coal-fired power plant and biomass incineration promoted by the local Greenwash Party
GRU's Developer Welfare Plan
http://freeforallcandidates.com/gruwelfare.htm

Regards,

Karen Orr
Gainesville, Florida

by Karen Orr at 3:38 PM on 15 Mar 2005

No diesel hybrids?

What? You say there's no such thing as a diesel hybrid? Not more than a hundred yards from where I live sits a brand new diesel hybrid bus from GM and 17-18 more are on the way. I live in Yosemite National Park and the Park Service has recently purchased cleaner, quieter, more user friendly diesel hybrid buses to replace our ancient 1986 retired city buses. Sure it's a bit big for the average family but the technology's been around long enough (we demo'd the bus in 2002) that if there were enough demand I'm sure a car could be built. And it seems to me that the increased battery capacity of a diesel hybrid could help to overcome the problem of keeping vegetable oil liquid when there's no engine heat. Here's a link to the NPS report about the new buses:
http://www.nps.gov/yose/planning/projects/shuttle.pdf

by gwmccull at 9:26 PM on 15 Mar 2005

Biodiesel emmissions?

I recently heard on my local NPR station (WAMU) that while biodiesel does reduce carbon and sulfur emmissions, NOx emissions increased. For anyone interested, they can listen to the broadcast here (real player format).

by mathemagician at 5:32 AM on 16 Mar 2005

Biodiesel and Emissions

Although Biodiesel does increase (although only slightly) NOx emmissions, it reduces several other key emissions.

The US EPA has done several key studies on Biodiesel emmissions.

This from the EPA Study:
http://www.utahbiodiesel.org/biodiesel_basics.html#EMISSIONS

"The overall ozone (smog) forming potential of biodiesel is less than diesel fuel. The ozone forming potential of the speciated hydrocarbon emissions was nearly 50 percent less than that measured for diesel fuel.

Sulphur emissions are essentially eliminated with pure biodiesel. The exhaust emissions of sulphur oxides and sulfates (major components of acid rain) from biodiesel were essentially eliminated compared to sulphur oxides and sulphates from diesel.

Criteria pollutants are reduced with biodiesel use. The use of biodiesel in an unmodified Cummins N14 diesel engine resulted in substantial reductions of unburned hydrocarbons, carbon monoxide, and particulate matter. Emissions of nitrogen oxides were slightly increased.

Carbon Monoxide
-- The exhaust emissions of carbon monoxide (a poisonous gas) from biodiesel were 50 percent lower than carbon monoxide emissions from diesel.

Particulate Matter
-- Breathing particulate has been shown to be a human health hazard. The exhaust emissions of particulate matter from biodiesel were 30 percent lower than overall particulate matter emissions from diesel.

Hydrocarbons
-- The exhaust emissions of total hydrocarbons (a contributing factor in the localized formation of smog and ozone) were 93 percent lower for biodiesel than diesel fuel.

Nitrogen Oxides
-- NOx emissions from biodiesel increase or decrease depending on the engine family and testing procedures. NOx emissions (a contributing factor in the localized formation of smog and ozone) from pure (100%) biodiesel increased in this test by 13 percent. However, biodiesel's lack of sulphur allows the use of NOx control technologies that cannot be used with conventional diesel. So, biodiesel NOx emissions can be effectively managed and efficiently eliminated as a concern of the fuel's use.

Biodiesel reduces the health risks associated with petroleum diesel. Biodiesel emissions showed decreased levels of PAH and nitrited PAH compounds which have been identified as potential cancer causing compounds. In the recent testing, PAH compounds were reduced by 75 to 85 percent, with the exception of benzo(a)anthracene, which was reduced by roughly 50 percent. Targeted nPAH compounds were also reduced dramatically with biodiesel fuel, with 2-nitrofluorene and 1-nitropyrene reduced by 90 percent, and the rest of the nPAH compounds reduced to only trace levels."

Here's some links to some pertinent information:
EPA Emissions Study
http://www.utahbiodiesel.org/biodiesel_basics.html#EMISSIONS
- This is the EPA's official website for presenting emission data on Biodiesel.

US Dept of Energy's analysis of Biodiesel
(Biodiesel Performance, Costs, and Use)
http://www.eia.doe.gov/oiaf/analysispaper/biodiesel/
- Very objective view of Biodiesel. Discusses pro's & con's.

NREL 2004 Biodiesel Handling and Use Guidelines
http://www.nrel.gov/vehiclesandfuels/npbf/feature_guidelines.html
-- This document outlines the fact that emissions (especially NOx) are impacted by the type of oil that is used to produce Biodiesel. It has to do with how saturated the base feedstock is.
-- It also outlines several key items in relation to Biodiesel.

Now my opinion:
=====
Although Hybrids help to reduce several key emissions (because they use electric motors at idle and etc), they aren't the "end all" to the emission problem. Biodiesel also reduces several of these key emissions, sometimes even exceeding them in a vehicle of same size & weight.

Another significant item of note is the fact that most diesel engines of similar size/weight have actually been known to get better gas mileage than even a comprable Hybrid. This means that size for size, a diesel consumes less fuel to run, and if run on Biodiesel, consumes no petroleum products to run.

Here's a nice site that show's benefits of different vehicles, compared side by side:
http://home.pacbell.net/tocho9/emission.html

by biofuels at 3:57 PM on 16 Mar 2005
[ Parent ]

Biodiesel Life Cycle

Just found a study from the NREL (National Renewable Energy Lab) detailing the life cycle of Biodiesel.
http://www.local23.org/biodiesel/lifecyclesummary.htm

Interesting....

by biofuels at 4:00 PM on 16 Mar 2005

Joe Deely

Heres a suggestion for the reader - buy a Terrapass.

see- http://www.terrapass.com/

by jdeely at 5:21 PM on 16 Mar 2005

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On hybrids vs. veggie-oil cars