Plug-in hybrid electric vehicles
Fact Sheet
PSE.com
PSE backing new transportation alternatives
What are plug-in hybrid electric vehicles?
Plug-in hybrid electric vehicles (PHEVs) are a type of vehicle that runs on electricity and has a gasoline or diesel engine
similar to a conventional hybrid vehicle. PHEVs differ from conventional hybrid vehicles in that they have a larger battery
pack that is charged by plugging into an electrical socket or specialized charger. The two PHEVs PSE has added to its fleet
are Toyota Prius hybrids that have been modified by installing an additional 5 kW battery pack and a plug to recharge the
battery pack.
How are PHEVs different than conventional hybrid vehicles?
• Compared to conventional hybrids, PHEVs’ larger battery allows them to
operate for a longer distance and at higher speeds on electric power alone.
• Conventional hybrid vehicles have a smaller battery that is recharged by
excess power from the car’s gasoline or diesel engine, or through energy
supplied by the car’s brakes when stopping. PHEVs have a larger battery or a
number of batteries, which can also be recharged by plugging the car into an
electrical socket or electric vehicle charger.
• Conventional hybrid vehicles use their gasoline or diesel engines more
frequently, while PHEVs are capable of operating on electricity alone
depending on the driving situation.
• Fuel economy of PHEVs is estimated to be up to twice that of a conventional
hybrid vehicle, with lower CO2 emissions.
Why does PSE have PHEVs?
PSE’s added two PHEVs to our fleet to help us better understand the energy
demands and infrastructure challenges presented by greater regional use of
electricity in transportation. The PHEVs are based out of our Bellevue corporate
offices and are used by employees on business trips throughout PSE’s service
area. Along with collecting data on the energy needs of the vehicles, PSE is
testing the equipment needed to recharge the vehicles. In addition, PSE is
monitoring the usefulness of software for assessing ways the vehicles can be
charged when there is low energy demand on the grid.
What would the impact be on PSE if electric cars became popular?
Many auto manufacturers are now producing plug-in hybrids or full-electric
vehicles. PSE has already looked at the effects that this may have on our system
and confirmed that it will not pose major problems for the utility. By incorporating
these plug-in hybrids in our fleet we have been able to learn when and how
much these vehicles charge. We continue to refine our studies and increase our
understanding as new information and technology becomes available to ensure
that we are well positioned to meet our customers’
energy needs.
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What kind of gas mileage are we getting?
PSE has put over 25,000 miles on the two PHEVs so far, initial test results show
mileage over 70 mpg when operating using the charged battery and overall
averages between 50 and 60 mpg. Conventional hybrid vehicles in PSE’s fleet
typically attain 40 to 45 mpg. The most important factor PSE has seen affect
mileage is where the cars are used, whether in town or long highway trips.
How many hybrid vehicles does PSE have in its service fleet?
PSE has had 37 conventional hybrid passenger vehicles in its fleet since 2008,
and more recently added two PHEVs and a hybrid diesel-electric line service
truck. The diesel-electric hybrid service truck offers greater fuel economy and
lower noise and CO2 emissions, and is used in our maintenance and operations
work as well as in our storm response efforts.
For more information:
PSE.com/ElectricVehicles