Summary of Clean Fuel / Clean Technology Options for School Buses

This chart summarizes the benefits, costs and applicability of various technologies discussed in the Retrofit
and Replacement Clean School Bus pages.

For a list of EPA's verified retrofit technology, please visit www.epa.gov/otaq/retrofit/retroverifiedlist.htm.
   Clean Fuel /
     Clean
   Technology
    Options
   Type of       Percent Reduction in
   Engine     Emissions of Particulate
                      Matter
    Percent
  Reduction in
  Emissions of
Nitrogen Oxides
Approximate Cost of
    Technology
Ultra-Low Sulfur
Diesel(ULSD)

Particulate Matter
Filter

Oxidation Catalyst

Compressed
Natural Gas(with
an oxidation
catalyst)
Biodiesel Fuel
B20: 20%
biodiesel, 80%
regular diesel
B100: 100%
biodiesel
Emulsified Diesel
Fuel

New or
Used Diesel
Engine
New or
Used Diesel
Engine -
1995 or
newer
models
New or
Used Diesel
Engine
New CNG
Engines

New or
Used Diesel
Engine
New or
Used Diesel
Engine
About 5 to 9%

Enables the PM filter
technology to work
60 to 90%


20 to 30%

70 to 90% if using catalyst
technology to reduce ultra fine
PM, formaldehyde, and
methane - otherwise, methane
and aldehydes will be much
higher than diesel engines

B20-10%
6100-40%
About 50%


N/A


N/A


N/A

About 60%
reduction but are
highly variable
(sometimes
increases occur)
Biodiesel
increases
emissions of Nox
slightly.
B20 blend +2%
B1 00 fuel +10%
About 10%


8 to 25 cents per gallon more
than regular diesel now
In June 2006, when ULSD will
be required nationwide, cost
differential will be much less
$5,000 to $10, 000

Must use ULSD fuel
$600 to $2,000 and can be
used with regular diesel
$30,000 more than a diesel
bus (cost of CNG fuel similar
to regular diesel fuel)
Very expensive special re-
fueling infrastructure and
maintenance facilities are
required
B20 - 1 5 to 30 cents per gallon
more than regular diesel
B1 00 - 75 cents to $1 .50 per
gallon more than regular
diesel (B100 may not be an
option for cold climates)
20 cents per gallon more than
regular diesel fuel

&EPA
United States
Environmental Protection
Agency
                          EPA-420-B-03-009
                    Updated December 2004

-------