What's the Difference between a Hybrid and a Plug-In Hybrid?

The Chevy Volt has been followed by controversy since its earliest days. Before it became available for purchase, GM described it as an "Extended Range Electric Vehicle;" this led the public to believe that the Volt would be a solely electric car that does not require gasoline. To many fans' disappointment, it turned out that the Volt is indeed a hybrid vehicle using both an electric motor and a conventional combustion engine rather than a purely electric-powered car. Since the official definition of a hybrid specifies that the vehicle uses at least two energy systems that both propel the car, the Volt definitely qualifies as a hybrid.

So what makes the Volt – or any other plug-in hybrid vehicle – different from something like the Toyota Prius, a regular hybrid?

Regular hybrids use a gas-burning combustion engine plus electric motor. With today's technology, the gas engine provides the main power to propel the car and the electric motor provides assistance on the side. The battery pack powers the electric motor as needed. Recharging occurs either from a generator that is spun by the gas engine or through regenerative braking, a system to capture energy that is normally lost to heat and friction during braking.

Regular hybrid vehicles are further characterized as either full hybrids or mild hybrids. A full hybrid vehicle, such as the Toyota Prius, can be propelled solely by electric power at low speeds and for short distances. A mild hybrid, such as the Honda Civic Hybrid, cannot drive only on electric power. In this case, the gas engine must run in order to drive; it turns off when the car coasts or idles.

Plug-in hybrids utilize a specialized type of battery that can be recharged from an electrical outlet in addition to the methods mentioned above. The electric motor functions as the main power source for propulsion with a secondary gasoline engine. As a result, plug-in hybrids can travel at higher speeds and for longer distances on electric power alone as compared to a regular hybrid. When the battery juice runs out, then the gas engine kicks in and the car operates as a conventional vehicle with standard fuel economy. As an example, most regular hybrids can only travel as far as roughly 15 miles and up to 25 mph on electric power alone, but the Chevy Volt goes from 25-50 miles and can handle speeds of nearly 100 mph without using any gas.

Plug-in hybrids generally need daily recharging, if not more often, depending on how they're used. If you drive the Volt less then 30 miles each day, then you're not using up gas; you just need to charge the car each night. But if your commute covers 70 miles a day, then you'll burn gas plus require nightly charges. A full charge takes just three hours, but finding a charging station today is tough; there simply aren't enough plug-in cars on the roads, and the infrastructure hasn't been built yet.

When it comes to the question of whether a regular hybrid or plug-in hybrid is the right vehicle for you, the answer will depend largely on how you will use the car and how comfortable you are with newer technologies. Plug-in hybrids cost more up-front, not including the home charging station, and carry lower fuel costs in the long run. However, because the gas engine does not run in concert with the electric motor – it runs after the electric motor has exhausted its battery juice – the fuel economy for the gas-driven miles is no better than any other conventional car.