Hybrid Electric Vehicles: Pros and Cons

Given the choice of a battery electric vehicle (BEV) with limited range that takes hours to recharge or a conventional one powered by an internal combustion engine (ICE), the vast majority of buyers opt for the ICE. That is why BEVs were beaten out by ICEs in the industry’s early days and have not competed effectively since. Advancing battery technology is increasing range and making BEVs more acceptable for daily use, but battery prices remain high and realistic (non battery damaging) charge times long.

Practical Alternative
A more practical fuel-saving and lower-emissions alternative is a “hybrid” electric vehicle (HEV), which marries the best attributes of electric propulsion and internal combustion into a single system. A typical hybrid can operate at low speeds on much more efficient, emissions-free electric power while offering ICE performance, flexibility and range when needed. It charges its batteries on the fly and, like ICEs, can be quickly refueled almost anywhere.

Parallel and Series Hybrids
Hybrids come in two basic types: parallel and series. A parallel hybrid blends torque from an electric motor and an ICE, typically through a complex electro-mechanical transmission, to drive its wheels. A series hybrid’s drive wheels, by contrast, are always electrically powered by batteries, which are charged at rest through a plug-in connection. The on-board ICE’s only role is to drive on-board generators to provide additional volts once its batteries are depleted.

Parallel Hybrids Available Now
“Full” parallel hybrids, such as Toyota’s Synergy Drive and Ford’s essentially identical system offer substantial fuel efficiency gains at low to moderate speeds and can run on volts alone for short distances before the ICE kicks in.


More complex and expensive “2-Mode” hybrids—offered by GM, Chrysler, BMW and Mercedes-Benz—add a second power mode that saves fuel at higher speeds as well.