Originally Posted by JoeV

First, I'd like to say welcome to this forum; I'm a new member. I've lurked for about a year. I don't currently own a hybrid, but have been interested in the technology and state of the art, in case we decide to purchase one in the future.

My high mileage vehicles are a 1998 VW Jetta TDI, and a motorcycle.

This discussion re: biodiesel interests me, as I've owned my TDI since I bought it new in 1998.

First, I don't want to unneccessarily upset those 'true believers' of biodiesel - I used to be one - but I have to make several points:
1) In theory, BD is a great renewable form of bio fuel; much more energy content than alcohol.
2) There are no manufacturers of diesel passenger cars and trucks in the US that authorize the use of a biodiesel blend of greater than 5%. There's a reason for this:
3) There are no standards of biodiesel manufacturing in the US. Nor is there a standards agency duly authorized to inspect and certify biodiesel is manufactured to a consistent standard. Type of oil, lubricity, etc are all CRITICAL to how a diesel engine will survive long-term. Not all veggie oils are the same. Nor are all biodiesel conversion processes the same. How much water is in the fuel? How much glycerin? How much filtering used in the process? How well was the veggie oil converted to synthetic diesel in the conversion process? What is the gelling temperature point?
4) Passenger car and light truck manufacturers are legally responsible for the long-term quality of their product. They will not sell a vehicle in the US to be authorized for use with high concentrations of biodiesel without these standards in place. And once in place, the engine systems have to be engineered to perform optimally - longevity (wear), emissions, performance, fuel economy - and thus the biodiesel must be engineered to perform similarly to petro-based fuel so that one design will work with both types of fuels.
5) The new ultra-low sulfur emissions systems being offered in upcoming diesel imports to the US are even less tolerant of biodiesel than were their predecessors. Ultra-low sulfur standards essentially has killed the future of biodiesel in the US. There was a reason the oil companies didn't really fight the new ultralow sulfur standards. These same companies already had ultralow sulfur refineries in Europe, so the technology was already in place.

EDIT: I understand that the new 'bluetech' emissions systems, in their various configurations (i.e. Mercedes uses urea injection, VW will not) are incompatible with bio diesel, and severe damage to these systems will result from the use of BD. So, sure; go ahead and run your 1978 VW rabbit diesel on bio. But in order for biodiesel to affect a significant change in the automotive culture, NEW CARS have got be compatible. They are not.

When there is a nationally recognized and enforced biodiesel manufacturing standard that is equivalent to those standards already in place in Europe, and the biodiesel industry is able to negotiate with the diesel vehicle manufacturers on a rational basis, then we may perhaps see biodiesel being used in new diesel passenger cars and light trucks.

Oh, BTW, I have no problem with do-it-yourselfers or small-scale businesses processing biodiesel and even selling it. But it's buyer beware. I will never put a blend of greater than 5% biodiesel in my car. It simply wasn't engineered to run optimally over hundreds of thousands of miles with a fuel of unknown manufacturing standard and content.

Maybe the tinkerers out there have no problem replacing engines with burnt pistons and ruined fuel injector pumps and nozzles; but I have better things to do with my time and property.

~Joe