While hybrid cars offer an improvement to conventional automobiles, Prof. John Callister ’96, mechanical and aerospace engineering, and Prof. Max Zhang, mechanical and aerospace engineering, agree that they are not enough. Zhang, Faculty Fellow in the Atkinson Center for a Sustainable Future, said that although “hybrids are leading us to a sustainable future, [they’re] not the solution we’re looking for.”Callister said that hybrid cars are more efficient than traditional vehicles because they use two power sources: an electric battery and a gas-powered engine. Callister explained that the most common way in which these batteries are charged is through a process known as regenerative breaking. Pumping the breaks turns a generator that provides resistance to stop the car while simultaneously making and storing electricity. This stored energy is then used during high load conditions, such as going uphill and accelerating. Since less oil is used to power the vehicle during these high load conditions, hybrids have an average more miles to the gallon. Zhang added that in the long run, using a hybrid vehicle reduces emissions even though production of the lithium ion battery is more energy intensive.
According to Zhang, creating the battery for a hybrid car causes the emissions of production to be higher than that of a conventional vehicle. Callister said that on top of the extra production costs, it’s more energy intensive to dispose of the lithium ion batteries in hybrids compared to the conventional lead acid battery used to start ordinary cars. He also said that the sheer number of batteries that need to be discarded is becoming a real issue, though Zhang mentioned the possibility of old batteries being used to store energy for various purposes, including household use.
More than two-thirds of the oil that we use in this country is imported and according to Zhang, our “foreign oil dependence is a national security problem”. Since “between 60 and 70 percent of the oil we import is used for transportation,” hybrid cars will help us decrease our oil dependency, but oil is still used to make and run hybrid cars. Callister said that an all-electric vehicle could be an efficient option depending on from where the electricity comes.
Likewise, Zhang supports the move towardusing sustainable energy to power electric cars. In fact he’s trying to help General Motors and Cornell make an agreement to add four Chevy Volts (hybrid electric vehicles) to the Cornell fleet, as the University is looking for more sustainable options. Zhang said that at this point, “the question of the electric car is whether we can make them cost competitive in comparison with the conventional internal combustion engine vehicles,” but “when we find new technology to make the batteries cheaper, the electric cars will be [cheaper] too.”
Going beyond technological options, Callister said that “we should really think about if personal transportation is even required,” suggesting that if people used to live without today’s luxuries, we could theoretically go back to that lifestyle.