Volkswagen’s Dr. Jens Hadler, executive director of powertrain development, said that stop-start devices—a very mild form of hybridization which shuts down a gas engine when the vehicle comes to a stop—can give clear savings, but a car with a full hybrid system, like the Toyota Prius, is too costly. He estimated that while stop-start systems could save 3 to 5% of CO2 emissions, a full hybrid like the Prius would save five times the fuel, but at 18 times the cost. Hadler sees this cost coming down with successive generations of hybrids, but not enough to make hybrids worthwhile in the future. This stance leaves little hope that Volkswagen will put its 70-mpg diesel-electric full hybrid Golf concept into production.
Franz Fehrenbach, CEO of Bosch, said that diesel hybrids, like the Golf concept, make even less sense than gasoline hybrids. According to Fehrenbach’s calculations, a gasoline full hybrid adds €2,000 to the cost of a car, but delivers only €1,500 in fuel savings over the first three years of the life of a vehicle. That’s a €500 loss over three years. The hole gets bigger with a diesel full hybrid, which adds €3,500 in cost but delivers €2,500 in savings, according to Fehrenbach.