Hybrid and Plug-In Electric Vehicles
Hybrid and plug-in electric vehicles use electricity as their primary fuel to improve the efficiency of conventional vehicle designs. This new generation of vehicles, often called electric drive vehicles, can be divided into three categories: hybrid electric vehicles (HEVs),
plug-in hybrid electric vehicles (PHEVs), and all-electric vehicles (EVs). Together,
they have great potential to reduce U.S. petroleum use.
Hybrid Electric Vehicles
HEVs are powered by an internal combustion engine or other propulsion sources that
runs on conventional or alternative fuel and an electric motor that uses energy stored in a battery. The extra power provided by the electric motor allows for a smaller engine, resulting in better fuel economy without sacrificing performance.
HEVs combine the benefits of high fuel economy and low emissions with the power and range of conventional vehicles.
HEVs do not require a plug to charge the battery; instead, they charge using
regenerative braking and the internal combustion engine. They capture energy
normally lost during braking by using the electric motor as a generator and storing
the captured energy in the battery. The energy from the battery provides extra
power during acceleration and auxiliary power when idling.
Plug-In Hybrid Electric Vehicles
PHEVs are powered by conventional fuels and by electrical energy stored in a
battery. Using electricity from the grid to charge the battery some of the time costs
less and reduces petroleum consumption compared with conventional vehicles.
PHEVs can also reduce emissions, depending on the electricity source.
PHEVs have an internal combustion engine or other propulsion source and an
electric motor, which uses energy stored in a battery. PHEVs have larger battery
packs than HEVs, making it possible to drive using only electric power (about 10
to 40 miles in current models). This is commonly referred to as the all-electric
range of the vehicle. PHEV batteries can be charged in several
ways: by an outside electric power source, by the internal combustion engine, or
through regenerative braking. If a PHEV is never plugged in to charge, its fuel
economy will be about the same as that of a similarly sized HEV. If the vehicle is
fully charged and then driven a shorter distance than its all-electric range, it is
possible to use electric power only.
EVs use a battery to store the electrical energy that powers the motor. EV batteries are charged by plugging the vehicle into an electric power source. Although electricity production may contribute to air pollution, the U.S. Environmental Protection Agency (EPA) considers EVs