Reality Checks    Introduction  Carbon neutrality    Misc Calculations    Meat vs biofuel  Air pollution  Options  Biofuel Bob

A joint study by the U.S. Department of Agriculture and U.S. Department of Energy found that biodiesel made from soybeans is 78% carbon neutral. Studies by organizations to promote their own products (note the soybean motif on the bus) are prone to bias. Independent verification is the cornerstone of the scientific method. Note also the disclaimer at the front of the report (admittedly, a necessary evil in our litigious society):

... Neither the United States government nor any agency thereof, nor any of their employees,
makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy,
completeness, or usefulness of any information...

The study referenced above did not account for things like:

Oil used to make fertilizers, herbicides, and pesticides.
Oil used to transport beans to crushing facility
Oil used to build additional crushing facilities depreciated over life of facility
Oil used to convert beans to soy oil
Oil used to build a refinery depreciated over life of refinery
Oil used to transport soy oil to a refinery
Oil used by refinery
Oil used to transport biodiesel to a gas pump
Greenhouse gases released to atmosphere from land use changes (conversion of carbon sinks to cropland)
N2O ( 300 times worse than CO2) released to atmospehre  from the nitrogen fixed from the atmosphere by crop.

The assumed  green house gas nuetrality of soy based biodiesel appears to be dropping. In 1998 it was 78%. A study done a few years later shows it to be 41% and two studies in 2007 (described below) have found that it may produce  more greenhouse gases than fossil diesel.  Of course, any vegetable oil crops grown on deforested or reclaimed conservation land is far from carbon neutral (deforestation is the second leading cause of global warming).

From this study: "Not all LCA models treat emissions the same, even when they are included. For instance, GREET does not include N2O emissions from atmospheric nitrogen fixed by soybeans, while LEM does, contributing to an almost order-of-magnitude greater estimate of GWI for soybean biodiesel."

Above table from the Journal Atmospheric Chemistry and Physics:

"Clearly, all past studies have severely underestimated the release rates of N2O to the atmosphere, with great potential impact on climate warming"

"The significance of it is that the supposed benefits of biofuels are even more disputable than had been thought hitherto. What we are saying is that [growing many biofuels] is probably of no benefit and in fact is actually making the climate issue worse."

From an article about this study:

"Rapeseed and maize biodiesels were calculated to produce up to 70 per cent and 50 per cent more greenhouse gases respectively than fossil fuels."

The research team included scientists from Britain, the US and Germany, and included Professor Paul Crutzen, who won a Nobel Prize for his work on ozone.

The above chart measures overall environmental impact of various fuels. The further to the right the bar extends, the worse the fuel is overall for the environment. From http://www.theoildrum.com/node/2976

Wait, there's more! A study just released in the Journal of Conservation Biology estimates that biodiesel made from rapeseed alone may destroy hundreds of thousands of square miles of forest/carbon sinks in the next few decades: http://news.mongabay.com/2007/1004-biodiesel.html

And what's this ( http://news.mongabay.com/2007/1112-hance_woodlark.html  )?

"On Woodlark Island, one-hundred and seventy miles from Papua New Guinea, a struggle is occurring between islanders and biofuel company Vitroplant Ltd. The company is planning to clear much of the island's forest for oil palm plantations to produce biofuels."

The vast majority of vegetable oil today goes into the human food chain, but when it is sucked off the food market to go into our gas tanks, somebody will clear more carbon sinks to make a profit on that increased demand. Rocket Science, this isn't.