What Is a Plug-in Hybrid?

By · September 29, 2016

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“I have always felt it was possible to build a car that gets more than 100 miles per gallon. It’s what this country needs: To build a car with high performance and all the fun factors of a conventional car, but have it run on electricity.”

Dr. Andy Frank
Widely considered the father of the modern plug-in hybrid

A plug-in hybrid car is similar to a conventional hybrid vehicle—both use a gasoline engine as well as an electric motor. However, a plug-in hybrid uses larger battery packs that can be recharged by connecting to common 120-volt household electricity or 240 volts from a home EV charging station. Plug-in hybrids can be driven for long distances—from a few miles to as much as 60 miles—without using any gasoline. (Learn about the different types of plug-in hybrids.)

Plug-in hybrids provide most of the benefits of an electric car while maintaining the same driving range as conventional vehicles--eliminating so-called "range anxiety" about plug-in cars. Plug-in hybrid drivers may travel in an all-electric mode for the vast majority of common local driving. When the battery’s electric charge is depleted, a downsized gas engine powers the car until the next opportunity to plug in and recharge the batteries.

Plug-in hybrid cars are also known as plug-in hybrid electric vehicles or PHEVs. Plug-in hybrid cars that use a gas engine exclusively for recharging batteries—rather than directly powering the wheels—are also called Extended-Range Electric Vehicles or EREVs or plug-in series hybrids.

Plug-in hybrid cars have considerable fuel efficiency benefits compared to other vehicles:

  • A hybrid car, depending on the model, achieves about as much as twice the fuel economy as a conventional car of the same size and capacity
  • A plug-in hybrid car can deliver about twice the fuel economy of a standard hybrid
Plug-in Hybrid Diagram

Common Plug-in Hybrid Criticisms

  • The extra batteries weigh too much.

    Response: The extra weight of the batteries will be offset somewhat by the reduced weight of the gas engine. At high speeds in particular, fuel efficiency is affected primarily by aerodynamics—the MPG is minimally affected by adding weight that's roughly equivalent to one or two additional passengers.

  • The extra batteries cost too much.

    Response: Any premium required for plug-in hybrids is less than the higher cost of a pure electric car (with its bigger battery pack). Regardless, once sold in high volumes by carmakers, more powerful and cheaper batteries can be sold at prices only a few thousand dollars above that of today’s hybrids. Several plug-in hybrids available today are available at prices barely higher than their gas-powered equivalents. Recharging will take place mostly at night during off-peak hours when electricity can be much cheaper. Despite the higher initial price (reduced by federal and some state tax incentives), counting purchases, fuel, and service, total lifetime cost of ownership is lower than a gas car.

  • Producing power from the grid (to charge the cars) simply switches pollution to the power plant.

    Response: What the industry calls "well-to-wheel" emissions (especially greenhouse gases) for grid-powered vehicles are far lower than gasoline, even for the average for the US power grid (which is 50 percent coal). Cars charging off-peak will use power from plants that can't turn off at night. Many parts of the country get most of their power from cleaner sources such as natural gas and hydropower. It's far easier to capture conventional emissions from a few centralized power stations than millions of aging cars. Finally, plug-in hybrids recharged with rooftop photovoltaic systems have virtually zero emissions.

New to EVs? Start here

  1. Seven Things To Know About Buying a Plug-In Car
    A few simple tips before you visit the dealership.
  2. Incentives for Plug-in Hybrids and Electric Cars
    Take advantage of credits and rebates to reduce EV costs.
  3. Buying Your First Home EV Charger
    You'll want a home charger. Here's how to buy the right one.