A Cautionary Tale About Biodiesel

The Volkswagen Jetta TDI + Biodiesel = A Match Made in Heaven?

When Volkswagen announced the Jetta TDI in 2008, we felt it was a very good car for the Green Shuttle business philosophy and fleet. The TDI is a diesel version of the Jetta that gets 40+ miles per gallon. We figured that burning a renewable biofuel in the TDI would be a great combination. We asked the Volkswagen dealership if using biofuel was permitted under warrantee, and the answer was a qualified yes: not 100% biofuel, but a maximum blend of 5% was acceptable. Volkswagen was and still is evaluating higher percentages but still doesn’t have sufficient data.

A 5% blend of biofuel can have a significant impact on our carbon footprint. For example, if everyone drove a Jetta TDI, imported fossil fuels could potentially be reduced by 5% and replaced with US-grown biocrops such as soy or canola, providing domestic employment and less dependency on imported fuel.

The Issue: Biodiesel Caused Emission Control System Failure

We added a Jetta TDI to the Green Shuttle fleet and immediately started using a blend of Biodiesel. The car ran perfectly until it hit about 100,000 miles, at which point we ran into issues with our emission control system. Although it was never stated directly or on the record, the service manager at Volkswagon implicated the use of biodiesel as the cause of the failure. The repair to the emission systems would cost an incredible $5,000.

The emission warrantee expires at 100,000 miles and we learned that if you are even one mile over, forget getting any of your expenses covered.

Recommended Solution: Run Straight Low Sulfur Fuel on your Jetta TDI

The Jetta TDI running straight low sulfur fuel is still a pretty green alternative but we would not recommend buying one with the intent of burning biodiesel.

Also, not all aspects of burning biodiesel are positive. The primary crop sources are soy and canola, both of which are food sources and the competition between fuel and food end use drives food prices up in a classic supply and demand scenario. Check out the prices on these commodities and you will see that they are at a record high!


There is a pot of gold at the end of this rainbow! Other crop sources are being evaluated for biodiesel, including algae and other non-food source crops as well. A strong partnership between private enterprise and government that pushes the development of biodiesel will pay large environmental dividends down the road. Richard Branson of Virgin Airlines has committed to burning biouels in his jets, and we at the Green Shuttle believe that visionary entrepreneurs such as Branson are key to making alternative fuel a reality.

In the meantime, unfortunately, we will not be burning biodiesel in our vehicles until we can be sure that the fuel is reliable and will not damage or shorten the useful life of our vehicles.

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Dean Athanas

Dean started the Green Shuttle after a long career in the manufacturing industry. He loves running a company that cares about the environment, but he loves interacting with his customers and drivers even more.

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