This chart summarizes the benefits, costs and applicability of various
technologies discussed in the Retrofit and
Replacement Clean School Bus pages.
| Clean Fuel / Clean Technology Options |
Type of Engine |
Percent Reduction in Emissions of Particulate Matter |
Percent Reduction in Emissions of Nitrogen Oxides |
Approximate Cost of Technology |
| Ultra-Low Sulfur Diesel(ULSD) |
New or Used Diesel Engine |
About 5 to 9%
Enables the PM filter technology to work
|
N/A |
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
|
| Particulate Matter Filter |
New or Used Diesel Engine - 1995 or newer models |
60 to 90% |
N/A |
$5,000 to $10,000
Must use ULSD fuel
|
| Oxidation Catalyst |
New or Used Diesel Engine |
20 to 30% |
N/A |
$600 to $2,000 and can be used with regular diesel |
| Compressed Natural Gas(with
an oxidation catalyst) |
New CNG Engines |
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 |
About 60% reduction but are highly variable (sometimes increases
occur) |
$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 |
| Biodiesel Fuel
B20: 20% biodiesel, 80% regular diesel
B100: 100% biodiesel
|
New or Used Diesel Engine |
B20 - 10%
B100 - 40%
|
Biodiesel increases emissions of Nox slightly.
B20 blend +2%
B100 fuel +10%
|
B20 - 15 to 30 cents per gallon more than regular diesel
B100 - 75 cents to $1.50 per gallon more than regular diesel (B100
may not be an option for cold climates)
|
| Emulsified Diesel Fuel |
New or Used Diesel Engine |
About 50% |
About 10% |
20 cents per gallon more than regular diesel fuel |
