The issue

Nearly every major automobile manufacturer has announced plans for selling plug-in hybrid electric vehicles (PEVs) over the next several years. The electric utility industry, among many others, is excited and supportive of this technology.

Electrification of transportation has the potential to:

  • Enhance energy security,
  • Provide environmental benefits,
  • Improve efficiency of vehicle fleets,
  • Create business opportunities/jobs,
  • Shape electric load with off peak charging,
  • Increase sales and use of electric energy (approximately 2 refrigerators = 1 PEV in terms of monthly kWh used).

Vehicle technologies

Hybrid Electric Vehicle (HEV) – runs on gasoline with motor/generator and batteries to improve fuel efficiency; does not use electricity from any external source

Electric Vehicle (EV) – runs only on an electric motor powered by batteries that are recharged by plugging in

Plug-in Hybrid Electric Vehicle (PEV) – Can be charged with electricity like pure electric vehicles and run under engine power like hybrid electric vehicles. The combination offers increased driving range with potential large fuel and cost savings, emissions reductions and other benefits

  • Parallel Hybrid – a PEV where both the electric motor and the combustion engine are mechanically coupled to the wheels through a transmission
  • Series Hybrid – (also known as an Extended Range Electric Vehicle or EREV) a PEV where the electric motor is directly coupled to the wheels and the combustion engine is used to charge the batteries.

PEV Technologies

Parallel Hybrid

Series Hybrid (EREV)

Deployment Drivers

  • Most manufacturers plan to begin production of EVs/PEVs in late 2010-2014
  • Vehicle price will be high due high initial battery cost
  • Dealer laws require automobile manufacturers to offer vehicles by state (not region or city)
  • Gas prices
  • Economic downturn likely to slow new vehicle purchases although federal tax credits ($2500-$7500 per vehicle) might counter economic conditions.

Converted Toyota Prius

Converted Toyota Prius
Source: AEP PEV

Beneficial Impact

Beneficial Impact
Source: EPRI


Fuel Economy/Fuel Cost Savings:
  • Converted Prius: 70 to 100mpg when assisted by battery
  • Could eliminate 2 out of 3 gallons of gasoline used

Energy Independence and Security:

  • U.S. imports 60% of its oil – 2/3 of which is for vehicle fuel
  • PEVs use domestic fossil fuels, nuclear and renewables


  • More torque and horsepower over a wider range of operating conditions

Environmental Benefits:

  • Net reduction in CO2 emissions

PEV Features

When a PEV’s battery is low on stored energy, an internal combustion engine takes over and either charges the batteries or directly powers the vehicle. An average light PEV would utilize electricity for 50 to 70 percent of its energy use over the life of the vehicle.