Chris Mi presents on hybrid and electric vehicles

Chris Mi, Ph.D. from the University of Michigan-Dearborn presented on hybrid and electric vehicles, arguing that the vehicles may offer a gateway to energy and environmental sustainability. These technologies are greatly overdue, hinted Mi, when one considers that 'peak oil' predictions show that oil will last only another 43 years at current consumption rates. Further, one must consider that increased emissions, including greenhouse gases (GHGs) that cause climate change are projected to only increase in the coming decades. This two-fold dilemma of energy and environment has caused scientists and engineers to begin developing new alternatives to gasoline vehicles. 

Hybrid electric vehicles (HEVs) may help to solve humanity's energy and environmental problems. HEVs have a number of key advantages, argued Mi, including that they allow for the optimization of the operating point of an internal combustion engine (ICE) and allowing for the ICE to stop if not needed. Also, HEVs recover the kinetic energy from braking allowing for greater overall system efficiency. 

The problems with HEVs are their high initial costs, reliability concerns, warranty issues, and safety with dealing with high voltage electrical systems. These problems will need to be overcome before HEVs will realize significant  market share gains.

Mi showed that other alternatives exist, such as plug-in hybrid electric vehicles (PHEVs). PHEVs come in multiple incarnations such as extended range electric vehicles (EREVs), blended PHEVs, and neighborhood electric vehicles (NEVs), each of which should be applied in different situations depending on a number of difference scenario characteristics. 

A major challenge in all hybrid systems is overcoming the weaknesses of the batteries. Mi shows how each battery type has its own set of challenges:

• Lead acid battery: energy density too low;
• Nickel metal hydride battery: ideal for HEV but still not without challenges;
• Metal air battery: not mature yet;
• Ultracapacitors: energy density too low; and
• Flywheels-energy density too low.

Mi showed optimism, however, when he argued that "everyone's working on this so hopefully there's a solution to all these problems in the next few years."

Another challenge, according to Mi, deals with how to properly evaluate and present the many HEV alternatives. One way to evaluate the vehicles is to measure how much fuel is displaced by operating a vehicle which uses electricity rather than gasoline. Even more importantly, according to Mi, is how you present this information to the public. Mi argued that the current window sticker included with every new car is simply not adequate. Mi suggested an appropriate labeling method be implemented which presents more useful information such as highway and city fuel economy ratings in all different modes of vehicle operation as well as presenting electric energy consumption and information on vehicle range when operating on electric mode. With more information it would become possible to evaluate what type of HEV would be appropriate for what scenario. 

In his closing arguments, Mi maintained that hybridization of vehicles is absolutely not the ultimate solution because the vehicles still rely on fossil fuels to some degree. However, HEVs will help build a pathway to a  sustainable future. Mi argued that a coordinated effort is needed across all modes of transport, such as undertaking smarter urban planning, better public transit systems, developing high speed rail, and building smarter and safer vehicles. Only through a collective effort by multiple stakeholders will we be able to break free of markets dominated by gasoline-powered personal vehicles.