^SmartWay
U.S. Environmental Protection Agency +
Hybrid Powertrain Technology
A Glance at Clean Freight Strategies
ENERGY & FUEL SAVINGS
Long Haul Hybrid
Gallons Saved:
1,333
gallons
CO2 Savings:
13.6
metric tons
Fuel Economy Increase:
9%
MPG (originaL 6 mpg):
6.5
mpg
Reduction in
Fuel Consumption:
8%
Fuel Cost Savings:
$3,880
Hybrid vehicles can provide about $3,800 in fuel savings in long-haul combination
trucks and cut greenhouse gas emissions by 13 metric tons per year. For stop-and-go
freight applications, a hybrid power train can save 4 metric tons of greenhouse gases
and save $1,000 in fuel costs each year. The amount of savings is highly dependent on
the drive cycle.
WHAT IS THE CHALLENGE?
When a truck decelerates or brakes, the kinetic energy of the moving vehicle is
typically lost to friction. This energy loss is particularly large for trucks operating in
urban areas, where vehicles make frequent starts and stops. If the kinetic energy of
a braking truck can be captured and harnessed, the truck can achieve better fuel
economy and lower emissions.
WHAT IS THE SOLUTION?
Hybrid powertrains are a technology used to capture energy and improve fuel
economy. Hybrid technology uses two power sources to move the vehicle, a main
source and a secondary source. The secondary power source is reversible and can
store and release energy. It captures the braking energy normally lost to friction, and
stores it for later use. The secondary power source can also provide an extra boost
to the main power source (usually an internal combustion engine) when the vehicle
needs more power, such as when climbing a hill or accelerating to pass. This usually
makes it possible to use a main power source that operates more efficiently. When the
main engine is downsized, other powertrain components, such as the radiator, can be
downsized as well.
One of the primary benefits of hybrid powertrain technology is the ability to reclaim
a portion of the energy otherwise lost to braking or deceleration. A variety of options
exist to capture and store this kinetic energy for later use. One option relies on electric
motors to convert the kinetic energy of the vehicle to electricity, which can be stored in
a battery or ultracapacitors, which charge quickly but are costly. Another option stores
energy as hydraulic pressure. Hydraulic flywheels have also been used to store the
kinetic energy for later use.
While the first commercial applications of hybrid powertrain technology have been
passenger vehicles, it is actually more efficient to place hybrid technology in heavier
vehicles like trucks. Since a vehicle with greater mass requires more power to stop,
more potential energy can be recaptured during braking or deceleration. Larger
vehicles also tend to have more available space for packaging the hybrid powertrain
components. Heavy-duty trucks typically cost more than passenger vehicles, so the
additional cost for the technology can be a smaller percentage of total vehicle cost.
EPA-420-F-19-020 | August 2019 | SmartWay Transport Partnership | epa.gov/smartway
(continued)

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Hybrid Powertrain Technology: A Glance at Clean Freight Strategies (continued)
ENERGY & FUEL SAVINGS
SAVINGS AND BENEFITS
Stop & Go Hybrid
Gallons Saved:
394
gallons
In pick-up and delivery service, it is estimated that truck fuel consumption can be
reduced from 25 to 50 percent using hybrid powertrain technology. Fuel savings depend
on the type of hybrid technology, the amount of regenerative braking energy, and the
amount of engine efficiency improvements. A typical long-haul combination truck could
save about $3,800 in fuel costs and reduce greenhouse gas emissions by over 13 metric
tons per year. Benefits for a typical stop-and-go truck include fuel savings of about
$1,000 and 4 metric tons of greenhouse gases each year. At least three major parcel
delivery companies are exploring the use of hybrid technology for step vans. Preliminary
results from some parcel delivery companies indicate hybrid trucks expect about a 40
percent improvement in fuel economy.
C02 Savings:

4
40%
metric tons
Improvement in /"N *»
fuel economy ^
Fuel Economy Increase:

33%

MPG (original. 6 mpg):
11.4
mpg

NEXT STEPS

^ Use hybrid power train technology in a fleet setting.
Reduction in

Set up an evaluation process to assess hybrid power train
technology with different fleet drive cycles.
Fuel Consumption:


25%

Fuel Cost Savings:

$1,145

Please visit the SmartWay website at www.epa.gov/smartway
to access more tech bulletins.
^vSmartWay
U.S. Environmental Protection Agency^

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