I really think that the eco-press needs to be a bit less bubbly about this 'alternative energy'.  I mean, running engines off of recycled cooking oil is great, but there's just not enough to run all our cars and trucks.  And not only do biofuels release carbon, their monocrop cultivation tends to occur along with unsustainable agricultural practises and, especially in South America, massive deforestation to make room for the new crops - which results in huge loss of biomass, oxygen production, erosion, habitat destruction, extinction of species and, oh, yeah, the release of a huge amount of carbon.

(they ran an article about this in the Guardian recently)

Someone remind me again why this is supposed to be environmentally beneficial?

The article in the Guardian mentions palm oil. I've seen a positive spin on use of the Jatropha tree (article) http://timesofindia.indiatimes.com/articleshow/1168744.cmsfor bio-fuel.  

I'm not expert on horticulture, but aren't these two different sources for bio-diesel?  

I've also read there is great interest in cellulosic material as a feedstock for ethanol.

From http://www.sprol.com/?p=188

The area that people deforest in Brazil every year is rising again. In 2005 it will pass the peak set in back in 1995.

The Mato Grosso state's governor is also the agriculture tycoon Blario Maggi, (known locally as "O Rei da Soja," the King of Soy) who clears rainforest to grow soybeans. Maggi is the largest producer of soybeans in the world. Mato Grosso led all Brazilian states in deforestation with 48 per cent of the destruction last year, feeding Brazil's booming Soya industry.

The key is to protect the forests, which we aren't doing now in a biofuel free world. Two different issues.

If we are having such a hard time protecting rainforests in a biofuel free world, how will we do so when the incentive to destroy them grows exponentially with the demand for biofuel? I wish I could just click my heels together and declare them to be two different issues, if they were, we would not be witnessing the destruction of rainforests by biodiesel right now. They are closely interrelated.

My part of the world is very dry but with a lot of artesian water.  I can see biofuel plantations happily sucking carbon out of our warming atmosphere.

Biodiesel puts far less CO2 into the air than conventional diesel but does not go so far as to suck carbon out of the atmosphere. It only sequesters CO2 for a few months before it spits it back into the air. It is also not entirely CO2 neutral, adding about 22% as much CO2 as conventional diesel while it is at it.

Biofuel crops can only be grown on arable land. To make unarable land arable takes a great deal of money. I could grow crops on Mount Rainier if I were willing to spend enough money. I won't because the resulting product would not be commercially competitive. It is far cheaper to cut down a rainforest than to do things like desalinate salt water or draw down aquafers to farm a desert. That is why biofuels will destroy jungles. It is also far cheaper to usurp existing croplands. People will not buy the most expensive biofuels produced by using expensive farming techniques on marginal farmland.

Cheaper biofuels that arrive in our ports will replace domestic production just as surely as cheaper products have replaced so many other American made products. We have a global economy now. Lower prices for consumers is what it is all about. How many people still insist on buying American even if it costs more?

Biofuel production in the US is supported by red state politicians because it is another way to subsidize farmers and for now, they have most environmentalists in their pockets. If word ever gets out that using biodiesel can double your ecological footprint score, they may end up with empty pockets.

Is it possible that, at the root of the fuel problem, is the fact that there's so much consumerism and such a high demand not only for vehicles of all kinds, but also for manufacturing processes that require petroleum? A few "2-cents worth":

Do y'all remember when gas supplies weren't a problem in the U.S.? That started a cycle which saw families moving to the suburbs, hence creating increased need for cars and fossil-fuels. I wonder: if fuel weren't as available then as it happened to be, would that migration to suburbs take place so thoughtlessly?

Now let's suppose that the fuel-supply challenge is solved with biofuels, hydrogen, solar power, you name it: what kind of consumerism cycle will that create? It seems like the more is available, the more consumers want.

So consumers not only need to be educated about the impact of fossil fuel usage, but also, there's a need for education where individuals would learn to live, leaving as small a footprint as possible.

Is it possible that different markets, with different renewable resources, should first aim to develop self-sustainable energy technologies, without vying necessary to supply fuel to others? That would take away the enticement of destroying forests and fields for the sake of exporting ethanol or whatever it may be. As an example: Brazil would produce enough renewable fuels for its own market, to the point where mass deforestation WOULD NOT occur. In the meanwhile, the U.S. would develop some other type of fuel - appropriate to its ecosystem - without, again having the ambition of creating so much of it, that its natural resources, quality of life, sustainability, ecosystems and biodiversity would be at risk.

According to the US Department of Energy, the amount of used cooking oil now disposed of in the U.S. exceeds the current potential demand for biodiesel fuel, making it an abundant resource (see "The Power of Biofuels" article, at SustainableReview.com.

Perhaps, at the end of the day, the answer to fuel supply is a bit like mutual funds: you don't put all your eggs in one basket! That is one thing I like about the premise behind the flex-fuel engine in Brazil, since it apparently doesn't create dependency on ONE specific type of fuel. Back in the 80s, in Brazil, so many cars were sugarcane-powered, that at one point, from what I have read, there wasn't enough of a supply. Now, I don't know WHY that happened, but it does teach us a lesson, doesn't it?

Some of the remarks could use a little clarification.

The amount of used cooking oil now disposed of in the U.S. exceeds the current potential demand for biodiesel fuel, making it an abundant resource.

What do they mean my "disposed" of and "abundant." In theory, there is enough used cooking oil in the U.S. to supply less than 5 percent of our cars. The fact that it can be burned in cars is irrelevant because it gets recycled anyway to make things like soap, or pet food. Using it to make biodiesel only takes it away from other recyclers, who would then have to use something else, like virgin vegetable oils. You can't get something for nothing. However, you can't ask for better PR and that's why biodiesel enthusiasts will mention recycled oil with every opportunity.

The biodiesel refinery in Seattle uses virgin vegetable oil shipped by train from the Mid-West. You can bet that they have very good reasons for using that instead of recycled cooking oil.

Biodiesel dramatically cuts air toxins, carbon monoxide, soot, small particles and hydrocarbon emissions in half.

This is true only when compared to regular diesel. If you want to reduce air pollution, drive an equivalent gasoline powered car. According to the Union of Concerned Scientists, and the EPA, they pollute less than biodiesel.

In fact, experts estimate about a third of our transportation fuel needs can be met by domestically produced biofuels.

Any idea who these experts are? My numbers show that we can fuel about 25% of our cars by growing soybeans on every square inch of cropland in the US. By using 10% of our cropland we can fuel 2.5% of our cars, reducing overall CO2 emissions by about half of a percent.