Norwegian research suggests biodiesel needs alternative handling to petroleum-based diesel.
With Norwegian diesel fuel containing as much as 7% biodiesel, links have been made to an increasing problem of clogged car filters, nozzles and reduced or lost engine power.
Biofuels are less stable than petrodiesel and deteriorate over time. Light, temperature and humidity increase the rate of deterioration. Researchers believe that colder climates and longer storage periods directly affect the fuel and need further research.
The EU requires specific standards of fuel quality when it leaves the production site. Professor Terese Løvås from the Norwegian University of Science and Technology (NTNU) questions whether this standard should be extended to the length of time biofuel can be stored, and under what conditions, without changing character.
"Biofuels contain oxygen compounds, which can lead to oxidation if the fuel is not processed and stored properly. The fuel then forms waxy substances that can clog filters and nozzles," says Løvås.
The oil industry denies that biodiesel is to blame for the problems. The Norwegian Petroleum Institute (NPI) claims there are few questions about problems with fuel grades and arctic fuel, in particular, is designed to withstand extreme cold. "Diesel fuel, both with and without added biodiesel, meets this [cold weather] requirement," says NPI's General Inger-Lise Nøstvik.
Further testing and extra fine filtration to remove wax particles before filling the tank with fuel will be costly and Løvås believes the oil companies will take some convincing that these are the correct solutions.
NPI is collaborating with engine manufacturers and oil companies to develop the European diesel standard.