Germany's Vanishing Veggie Diesel
Europe, and especially Germany, reports declining diesel dependency. From a nearly 50 percent share a few years ago, the share of diesel driven cars in Germany dropped to 31 percent in 2009. Two reasons: The favorable taxation of the oil had been scrapped. And speaking of scrapped, the “Abwrackprämie, or cash for clunkers, had favored a trend towards low displacement gasoline burners. (In January, the diesel share climbed back to 40 percent in Deutschland.) Badly mauled were the manufacturers of bio (a.k.a. “veggie”) diesel.
Attracted by governmental largesse (the former red-green government promised to totally strike the tax on veggie diesel,) many companies started to produce the supposedly green oil. Now, reports Das Autohaus, [sub] around half of the 50 makers of biodiesel in Germany have gone bankrupt, or stopped the production of biodiesel.
Again, the tax man did it: Contrary to former promises, the tax for pure veggie diesel was raised to 18 cents per liter in 2009. In 2013, the allegedly environmentally friendly fuel will be taxed similarly to fossil fuel: Regular diesel carries a tax of 47 Euro cents per liter in Germany, veggie diesel will cost 45 Euro cents in contributions to the government. No wonder the makers of green fuel go into the reds.
Bio-fuels and sustainability - It does come down to using food crops as fuel. Why does ethonal and sugarcaine work in Brazil? It grows like a weed without irrigation, fertilizer and pest/herbacides and produces 7 units of energy for every (1) input to process. Corn on the other hand requires all of the above (plus massive human intervention to sustain (it is a man made crop after all) and produces 2 units for 1 input. If you really wanted it to work in US, it's hemp (especially genetically/selectively bred). Grows like a weed, requires no irrigation, fertilizer, etc. (doesn't compete with food crops)and produces ethonal at 5/1, bio-diesel at 3/1 (in comparison to soy beans) and 5/1 as much wood pulp/lb in comparison to wood. (now can you think of three industries/lobbying groups that would do whatever to keep that from happening?) Best bet really is CNG, along with LPG and Diesel (looks like water, has almost no smell and none of the other things in deisel that lead to particulate matter (sulfur, etc, allowing removal of alot of the complex systems that currently make D engines so much more expensive) processed from LNG refining (converting of LNG to CNG for use also produces LPG and can be furthur processed into Deisel as well other compounds used in organic chem. compounds, plastics. But once what lobbying groups wouldn't want to see this happening? I find it very frustrating that what should have been a good plan in the US, was really nothing more than the politicals just transferring (borrowed) wealth to powerful interest group(farmers), subsidized by the food $ that we all need to survive. All while creating a non-sustainable industry that just serves as another transfer of wealth to wall street/main street. Trickle down economics at it's best (accomplished nothing, except making the rich richer and all other classes poorer) alot of gramm. errors sorry.
The same thing is happening in the US. The Federal Biodiesel subsidy of $1/gal expired at the end of 2009. The industry is in tatters, running at 15% of capacity. We should have covered this more, but it slipped by:
Particulate emissions aren't directly related to Sulfur in fuels. I'll agree with colin42; PM is due to incomplete combustion of the hydrocarbon fuel. Diesel's main/characteristic hydrocarbon is a long linear carbon chain. During combustion each carbon bond must be broken and all hydrogens broken off to completely oxidize the fuel. Invariably due to localized oxygen deprivation or the cooling colin42 mentioned some of those bonds will be left unbroken. The longer the remaining chain of carbon atoms the more likely that it will group with other remaining carbon chains to produce particulates. Gasoline's main/characteristic hydrocarbon is a much shorter and branched carbon chain (not all carbon atoms are in line, and there are carbon atoms bonded to three other carbons rather than just one on each side) that facilitates the breaking of carbon bonds and improved ability to oxidize. The result is fewer and shorter remaining carbon chains, thus less and smaller particulates. Direct diesel injection greatly reduces PM by injecting fuel at higher pressure with fancier injectors to improve atomization (making vaporization quicker and more likely to complete during combustion as unvaporized liquid becomes PM) and more turbulence in the combustion chamber. Gasoline direct injection benefits from the same things, combined with the fuel's inherent tendency to produce fewer/smaller particulates. I don't think PM emissions will become an issue with GDI engines. edit: for visual reference of the comparative molecule sizes and shapes look at the Wikipedia articles. Gasoline (octane, isooctane, is really 2,2,4 Trimethylpentane)- http://en.wikipedia.org/wiki/2,2,4-Trimethylpentane Diesel (cetane, really hexadecane) - http://en.wikipedia.org/wiki/Hexadecane
Two late comments from me (I was out of the country): Diesel fuel still has a tax avantage in Germany, as in many other countries. Diesel is taxed per liter (/gallon) and not per energy unit. But Diesel packs more energy per liter. So any regime that taxes Diesel at the same rate as gasoline is giving Diesel an (unfair) advantage. Rapeseed / Canola - based Diesel as Chuck G said, is a relatively benign fuel. I'd like to add that rapeseed is a soil improver and not necessarily a food replacer. A farmer can sow rapeseed every four or so years, and his crops will benefit as a general result.