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Natural Gas
The Right
and the Denve
A Response to RTDs Staff Prese
Operations Committee o
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T
The Regional Transportation District (RTD) has a loissuing diesel-only new bus RFPs for standard heaConsequently, RTD taxpayers and commuters are quieter heavy-duty natural gas buses used by othethroughout the country.
Given the performance, durability and emissions adcompetitive cost; given substantial federal and statincentives; given the Denver metro-regions non-coFederal ozone standards for the third consecutive yColorado is a major natural gas producer; and givereliance on foreign oil, we believe natural gas is byresponsible heavy-duty bus option for RTD taxpaye
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Sample Transit A
Using Natural G
375?San Diego
241Sacramento RT
324Atlanta
32Denver Intl Airport
176Pierce Transit (Seattle, WA)
221New York
120Foothill (Pomona, CA)
24Culver City, CA
56SunLine (Palm Springs, CA)
375Boston
2,000Los Angeles MTA
543 (Liquefied naturaPhoenix
24Santa Fe (7,000 ft)
60Albuquerque (5,000 ft)
# of Natural Gas BusAgency
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Int
Compressed natural gas (CNG)transit bus engines offer thelowest emissions commerciallyavailable1
All but one major transit busmanufacturer in the United Statesbuilds CNG transit buses
22% of all new buses on order inthe United States are CNG2
CNG transit bus engines are thequietest commercially available
Los A
Man
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Int
CNG transit buses are costcompetitive with diesel buses
In cases where CNG transit busbids are higher than diesel,outside funding sources usuallycover the incremental cost(CMAQ, FTA, etc.)
Clean Energy will pay anyincremental cost incurred byRTD up to $10,000 per bus
along with a multi-year fuelingagreement In addition, Colorado offers a
State tax credit for dedicatedCNG vehicles
Cu
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Int
Transit agencies throughout the country/worldoperate CNG Transit buses successfully The successful operation of 32 CNG buses at
DIA for the last two years proves that CNG busesfunction well at our altitude.3
The City of Santa Fes CNG transit fleetsuccessfully operates at 7,000 feet anddemonstrates that CNG buses function well athigher altitudes.4
Colorado is a major natural gas producer Use of natural gas vehicles support our local
economy.
Use of natural gas vehicles reduces ourdependence on foreign oil.
According to the US DOE Energy InformationAgency, the United States currently imports 63%of our oil.
Orange C
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In
On April 15, 2004, EPA Region 8 will designate theDenver region as a non-attainment area for the Federalozone standard.5
NOx is a primary contributor to ozone, thereforereducing NOx emissions will help reduce ozone.
By 2007 all new bus purchases in the United Statesmust meet much stricter Federal emission standards. CNG transit buses built today already meet 2007
Particulate Matter emission standards, while the mostadvanced diesel engines built today do not meet thesestandards.
By purchasing CNG transit buses now, RTD is well positionedto demonstrate emissions compliance now and in the future.
RTD has the largest heavy duty diesel fleet in the metroregion with over 1100 buses.
When compared to other heavy duty fleets in theregion, RTD is arguably the largest source of mobileNOx emissions.
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Int
The presentation to the Operations Committee on January 9,2004 was critically flawed for multiple reasons:
Staffs presentation compared 2003 clean diesel enginesequipped with emission control systems that require Ultra LowSulfur Diesel fuel with circa 1996 CNG engines.
Staff has not disclosed the engine and fuel technology they
intend to procure (e.g., conventional diesel vs. clean diesel)
Staff overlooked the maintenance and training costs for theseemission control systems associated with clean diesel
Staff did not report that emissions control systems used to cleanup diesel engines (such as particulate filters) cause majorproblems in other transit fleets.6
Ultra Low Sulfur Diesel fuel is not commercially available in
Colorado.
If and when Ultra Low Sulfur Diesel fuel is commercially availablein Colorado, RTD will pay a premium for the fuel. Thepresentation ignored this fact.
Costs for operating natural gas buses was exaggerated.
W
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Wha
ppm = parts per million
Ultra Low Sulfur Diesel (
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Emissions Regio
For the past three years, the Denver region has failed tomeet the Federal ozone standard.
On April 15, 2004, EPA Region 8 will designate theDenver region as a non-attainment area for the Federalozone standard.
RTD is not currently a partner in the metro-regionsEarly Action Compact, a voluntary agreement with the EPAto return our region to compliance with the Clean Air Act.
RTD operates the largest heavy duty diesel fleet in themetro region with over 1100 buses.
When compared to other heavy duty fleets in the metroregion, RTD is arguably the largest source of mobileNOx emissions.
Should FasTracks be approved by voters, the region willneed to anticipate emissions impacts from two sources.
Operation of FasTracks construction equipment Increased idling due to construction related traffic
delays
San Diego M
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Emissions Co Emission results from CNG buses equipped with a catalyzed p
clean diesel bus equipped with a diesel particulate filter using
Ultra Low Sulfur Diesel is not commercially available in Colora
With NOx being a major contributor to ground level ozone andproblems, CNG offers superior emission benefits
0
0.01
0.02
0.03
0.04
0.05
Particulate
Matter (PM)
0
1
2
3
4
5
6
7
8
NMHC\THCx10
0
6
12
18
24
30
36
42
48
Oxides of Nitrogen
(NOx)
0
3
6
9
12
15
18
21
24
27
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2003 Diesel vs. CNG Em
CalifoUC Davis an
0
5
10
15
2025
30
35
Diesel
(DOC)
Diesel
(DPF)
CNG CNG-1
(OC)
CNG-2
(OC)
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What does th
about natu
diese
The next slide shows EPA-certifiefor diesel and natural gas engine2002 and 2003.
The natural gas engines results in the lower left where both majo
nitrogen oxides (NOx) and partic(PM) are much lower than dies
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Todays Heavy-Duty
Natural Gas E
Engine
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.0 1.0 2.0 3.0
NOx (g/bhp-hr)
PM(
g/bhp-hr)
ource: DOE 1/28/03 Presentation
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S
Emissio
Die G/HP
NOx NMHC
EPA Standard 2.5 NOx+NMHC
CARB Standard 1.8 NOx+NMHC
S50G 275 BHP With Catalyst 1.2 NOx+NMHC
S50G 275 BHP No Catalyst 1.9 NOx+NMHC
S50G Cont. Dev. No Catalyst 1.8 NOx+NMHC
Source: DDC Presentation, 10/22/02Source: DDC Presentation, 10/22/02
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What does
Westport say abo
gas
Our spark-ignited (natural gas) eng
reductions of up to 90% for particula(PM), up to 24% for oxides of nitrogup to 10% for carbon dioxide (CO2) with 2004 diesel standards.
Source: Cummins Westport Clean Engines 2002. Cummins Westport is the other majoengine supplier.
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How do future
natural gas engines
0.00.0130.1040.117Low emission CNG
engine4
0.03.0Green Diesel
Technology3
00.22007 EPA Standards2
02.52002/20041 EPA Standards
PNMHCNOxNOx +
NMHC
1 Originally these standards took effect in 2004, but HD diesel manufacturers agr
consent decree in response to EPAs claim that they cheated on earlier emissio
2
These standards are phased in starting in 2007.3 T444E school bus engine using Green Diesel Technology as reported on Inte
Technology website, 4/03
4 Low-emission 6.0 L CNG stoichiometric TWC engine developed under DOEs
by Dr. Alex Lawson, TeleflexGFI Control Systems, 12/2/02 and 4/3/03.
5 Actually reported as 0.19 rounded to one significant figure to compare with
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Per
Noise
Efficiency
Durability
Range Fueling
Maintenance
Our 2002 CNG buses out performed o
-Mike Quirk, Maintenance Manager, First Tran
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0
20
40
60
80
100
120
140
Jet Engine at
300 ft.
Jackhammer Diesel Engine
(Full Load)
Busy Urban
Street
NG Engine (Full
Load)
Diesel Engine
(No Load)
Garbage
Disposal
De
cibelLevel
It is important to understand that the difference between decibels is an exponentiameasurement. For example, one idling heavy duty diesel engine is louder than ten combined.
Natural gas buses are dramatically quieter than their diesel counterparts a benefimage enhancer for transit agencies.
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Staff presentation appears to claim conventional heavy-dutydiesel transit buses typically achieve 4.6 miles per gallon (mpg)vs. 3.7 mpg for comparable CNG buses.
Reality: The national MPG average for heavy-duty dieseltransit buses is between 3.5 and 4.0 MPG althoughMPG varies depending on engine and bus size, use of air
conditioning, the bus route and other variables. (Source:Dwight Hanson, Western Regional Manager, CumminsWestport)
Reality: If staff procures Clean diesel buses requiringadvanced emission control equipment and Ultra LowSulfur Diesel, fuel efficiency will drop to between 3.3 and3.8. (Source #9)
Reality: CNG transit buses regularly achieve between 3.3and 3.5 MPG. Again, MPG varies depending on engineand bus size, use of air conditioning, the bus route andother variables. (Source: Bob Bach, Operations Manager,OmniTrans)
New
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Staff presentation claimsconventional heavy duty dieseltransit engines have a life of300,000 miles while
comparable CNG engines havea life of only 150,000 miles
Reality: CNG transit busesregularly achieve over 400,000
miles before requiring firstengine overhaul10 OmniTrans (Sa
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Staff claims the maximum range fobuses is only 350 miles vs. diesel tbuses with a range of 450 miles.
Reality: RTDs RFP can and shoubus operating range which, in turn,on-board fuel storage capacity.
Reality: Natural gas buses are conprovide 400-500 mile range.
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Staff claims fueling time foris 3-minutes per bus while ffor CNG buses is 15-20 min
Reality: Transit agencies across the Usuppliers to meet 8-minute fueling time
Reality: Fueling time comparison is laStandard operations dictate bus cleanipreventative maintenance occur simu10-15 minute window.
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Denvers natural gas is oftemischaracterized
Staff refers to the Denver-metro regions natural gquality and/or possessing 10% less energy than timplying this somehow equates to less fuel econo
performance or higher emissions.
Reality: While the Denver-metro regions natural10% fewer BTUs per cubic foot than the national absolutely no relationship to engine performance,RTD buys natural gas based on the energy contaequivalent gallon of diesel fuel. The question for
Reality:As a practical matter, the 10% lower BTU10% larger on-board fuel storage vessels. RTDs range. Bus range, in turn, dictates the size of thestorage vessels. Clean Energy charges RTD onlycontent, not for the fuels spatial volume.
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Ma
Staff claims no additional training is needed fbuses, whereas CNG transit buses require mand personnel training.
Reality: In order to meet EPA Clean Air stan
and complicated diesel emissions control syThese systems demand additional training a(NYMTA)12
Staff claims 4,300 miles between road-calls f2,100 miles for CNG.
Reality: Road-calls are not an accurate port
reliability, because the term road-call inclubroken wheelchair lifts, as well as mechanicmean time between engine failure is a morereliability measure.
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Cummins C Gas PluSatisfaction Surve
Cummins is one of the leading enginemanufacturers for transit buses.
Majority of Cummins customers using its CNGengine rated the C Gas Plus model excellent orgood on 7 of 8 criteria. Low Emissions
Ease of Servicing Safety
Driver Satisfaction
Low Noise Levels
Availability of Parts
Frequency of Engine Breakdowns
Engine is rated by 88% of customers as animprovement over its predecessors C8.3G andL10G.
70% of managers reported that the C Gas Plus hasimproved their perception of natural gas enginesoverall.
90% of managers are likely to repurchase the C GasPlus.
S
(
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Capital Cos
Staff claims CNG buses costs $30,000-$50,000more per bus than for comparable diesel buses.
Reality: Recent bids show CNG buses arecost competitive with diesel buses.14
Reality: In a recent large bus procurement, theincremental capital cost was $7,000 per bus.14
Reality: The cost differential for RTD isunknown because RTD excludes natural gasbuses from its RFPs.
Reality: FTA will likely reimburse RTD for 95%of any incremental procurement cost.
Reality: Clean Energy will pay any incrementalcost up to $10,000 along with a multi-yearfueling agreement.
Pierce
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Capital Cost
Staff claims a new CNG fuel station for 63-100buses will cost $2-$4 million.
Reality: Very large CNG fueling stations do cost $2-4 million however, at several transit agenciesincluding Los Angeles and Boston the FederalTransit Administration covered 100% of the cost of
the natural gas fueling station.
Reality: In the event FTA does not provide funding,private fuel suppliers can amortize the cost over thelife of the bus, so there is no additional upfront costto RTD.
Reality: For 63 buses the CNG fueling station
would cost about $1.25 million, half of what staffclaims.
Reality: RTD spent $0 on the existing CNG stationfor the mall buses 100% of the upfront cost wascovered by Clean Energy and recouped through amulti-year fueling agreement.
Bos
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Maintena
Staff claims CNG buses are 60% more expensiveto maintain.
Reality: Pierce Transit in Seattle, Washingtonreports CNG costs $0.36/mile to operate anddiesel costs $0.58/mile to operate (parts, labor,fuel, lubricants, and tires).15
Reality: Significant engineering improvements inCNG engines are pushing the costs per miledown while pushing up the cost per mile for newdiesels due to complicated and expensiveemission control systems that advanced dieselsdemand.
NYMTA reports that diesel transit buses equipped
with particulate matter traps increase maintenancecosts by $300-$600 per bus per year. Additionally,the required replacement filters cost $2,600-$5,000per filter, required by Clean Diesel technology. 16
NYMTA also reports that NOx control systems andPM traps in combination cause additionalmaintenance issues and conflicts.16
Phoen
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0 500 1000 1500 2000 2500
Diesel
L10 Ph I
L10 Ph II
L10 Ph III
C8.3G
C+8.3G
Better
Oil Consumption
0.0 1.0
Diesel
L10 Ph I
L10 Ph II
L10 Ph III
C8.3G
C+8.3G
Fuel C
Operating Costs: Pierce
Standard CNG engine
available from Cummins
(engine used by RTD)
Miles per quart Miles per dies
$- $0.20 $0.40 $0.60 $0.80
Diesel
L10 Ph I
L10 Ph II
L10 Ph III
C8.3G
C+8.3G
Total Cost Per Mile
*Includes parts, labor, fuel, lubricants, and tir
$0.00
BetterIts a bit deceiving
because over half of the
diesel buses that we
continue to operate, are
running in express
freeway servicea
service that is easier on
the hardware.
Ron Shipley, Pierce
Transit
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Operating Costs: Sac
0 50 100 150 200 250 300 350 400 450 500
Consumption
iles per quart)
CNG
Diesel
0 1
Fuel Economy
(MPG)
0.68 0.7 0.72 0.74 0.76
Cost Per Mile
Source:
Sacramento RT,
July 2003 December 2003
Monthly
Maintenance
Report
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Staff claims cost for diesel is $0.90 pergallon and CNG costs $1.56 per gallon.
Reality: Clean Energy currently charges$1.56 for CNG at its very low volumestations (less than 2,000 gallons per
month) which includes the RTD Bouldersite (3, 30 buses circa 1998) which RTDcommitted to use in excess of 10,000gallons per month, but only dispenses600 gallons per month.
Reality: We anticipate RTDs cost forstandard diesel to be $0.93-$0.98 pergallon in the coming years depending on
the price per barrel of oil.
Reality: Even if Ultra Low Sulfur Dieselwere available in Colorado (and itsNOT), the cost per gallon would likely bebetween $1.05-$1.13.
Denver Inte
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Natural G
CNG and LNG pricing is based onseveral factors Natural gas commodity
Compression cost (CNG)
Operation and Maintenance
Transportation/liquefaction (LNG) LNG is transported over the road similar
to diesel
Monthly/annual gallons dispensed The more gallons dispensed lower the
cost for operation and maintenance
Station capital can be amortized over 10
year period, exact cost per gallon isdependent on station size, and annualgallons dispensed
At Clean Energys sites where it mustrecoup the initial station capital, fuelprices are higher
CompressionCost (electricity
TOTAL perdiesel gallonequivalent
O&M ( labor,parts, fixedcosts, profit)
Liquefaction &
Transportation(from Ignacio)
Commodity @$4.75/MMBtu
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In addition, emission control systemsthat will be required on new dieselengines will decrease fuel economy by3-7%.17
Based on current natural gas prices, thefuel costs, including station operation(maintenance, electricity), ranges from$0.85 to $1.06 per gallon.
RTD has the option of purchasing multi-year fixed price natural gas contracts,thereby creating budget predictability.
Phoenix I
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Fundin
No additional funding may be needed if CNGbids come in at or lower than diesel bids
If natural gas bids come in higher than dieselthere are several sources of funding: Federal Transit Administration (FTA)
As long as RTD owns the bus, FTA willreimburse RTD for 95% of any incrementalcost for natural gas buses
Additionally FTA often reimburses transitagencies for the natural gas relatedinfrastructure improvements (i.e. fueling station
and garage modifications) Clean Energy will pay any incremental cost
up to $10,000 along with a multi-year fuelingagreement
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Fundin
Congestion Mitigation and Air Quality
US Department of Energy State Ene Regularly funds CNG projects up to $150,
incremental capital cost
Tax credits Existing Colorado State Tax Credit
If buses are purchased by RTDs contractoRTD operator can take a 50% tax credit cost
Pending Federal energy bill includes tax cwould cover 80% of incremental cost
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Natural Gas
wi
22% of all new transit buses on ordernatural gas19
Other countries see the future and arCNG powered buses. For example, China 90% of their 18,000 bus fleet wgas by 200718
Of the 2,300 transit buses operating over 2,000 operate on CNG
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Given the demonstrated cost, emissions, perforadvantages of natural gas buses, RTD should abuses to compete in all new bus RFPs.
Its proven that natural gas buses have lower emdiesel buses (particularly NOx) and will continue
emissions into the future.
CNG engines are noticeably quieter than diese
Current CNG buses are more than cost competcompared to diesel buses given the tremendous
secure multiple Federal, State, and private sec
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The emission reductions from CNG buseemission increases associated with FasTconstruction.
CNG fuel suppliers can provide 100% of tthe fueling infrastructure as part of a longagreement.
If the region goes into Ozone non-attainm
potential loss of Federal Highway funds.
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Diesel Health Impacts & Recent
Comparisons to Other Fuels
Diane Bailey, Staff Scientist,
Natural Resources Defense Council
DEER Conference, San Diego, CA, August 2002
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NRDC
The Natural Resources Defense Council is a national,non-profit organization of scientists, lawyers andenvironmental specialists dedicated to protecting
public health and the environment.
Founded in 1970, NRDC has more than 500,000members nationwide, served from offices in New
York, Washington, Los Angeles and SanFrancisco.
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General Health Effects of Diesel Exhaust
General Acute Exposure Effects: Nausea, eye irritation,
increased blood pressure, headache, light-headedness, loss ofappetite, poor coordination & difficulty concentrating.1
Diesel Particulates (PM) and Nitrogen Oxides (NOx) are
responsible for a wide array of health problems.
Typical Diesel exhaust contains up to 40 different air toxics,including arsenic, dioxins, formaldehyde, lead and mercury
compounds.
Listed as a Toxic Air Contaminant (TAC) by the Cal. Air
Resources Board in 1998.
1Agency for Toxic Substances and Disease Registry, http://www.atsdr.cdc.gov/tfacts75.html
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Diesel Exhaust Particulates
Diesel exhaust is a major source of fine particles, which can
lodge deep in the lungs, carrying other air toxics with them.
Numerous studies have shown that fine particulates:1
Impair lung function
Aggravate respiratory problems: Bronchitis, emphysema,asthma
Are associated with premature mortality.
Generally, health risks from fine PM exposure in most largecities translates to a 20% increase in risk of developing lungcancer for a nonsmoker. This is analogous to living with a
smoker.2
1 Pope et. al., J. Am. Medical Assoc., 287:1132-1142, 2002.2 Hood., Environmental Health Perspectives, 110:A456, 2002.
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Particulate Related Mortality
Many studies tie fine PM to increased hospital admissions
for respiratory diseases, chronic obstructive lung disease(COPD), pneumonia, and heart disease, including elevatedrisk of acute myocardial infarction (heart attack).1
An NRDC study of 239 U.S. cities estimated an annual deathtoll of 50,000 due to fine particulate pollution.
U.S. EPA estimates that 8,300 premature deaths will beavoided annually by 2030, due to the 2007 On-Road Heavy-duty Diesel Engine & Fuel Standards.2
1 Peters et. al., Circulation, 103:2810-2815, 2001.2 Tables VII-19 & 22, Regulatory Impact Analysis Document
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Carcinogenic Effects
The State of California classified Diesel exhaust as a knownlung carcinogen in 1990. Numerous other agencies U.S. &International consider diesel exhaust likely to be
carcinogenic.
Scores of studies have shown that long-term exposure todiesel exhaust is associated with significantly increased risk
of lung cancer.1
Many other types of cancer have been linked tooccupational exposure to diesel exhaust, including bus &truck drivers, garage workers, railway & dock workers andothers.2
1 CARB & OEHHA, Report to the ARB on the Proposed Identification of Diesel Exhaust as a TAC,
Executive Summary as approved by the SRP on April 22, 1998, ES-20.2 Boffetta et. al., Cancer causes Control 12:365-374, 2001.
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Cancer Risk Statistics
Government regulators estimate that diesel exhaust is
responsible for 125,000 cancers nationwide, based onlifetime exposure. (STAPPA/ALAPCO, 2000)
Studies in California reveal that more than 70% of cancerrisk from air pollution comes from diesel exhaust alone.
(SCAQMD, MATES II, 2000)
A recent analysis of U.S. EPA inventory data shows even
higher percentages of cancer risk from diesel exhaust: 78-90% of the total risk from HAPs in the U.S. (ED, based onNATA, 2001)
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Diesel & Asthma
According to numerous studies, diesel exhaust is associatedwith asthma, which is rapidly on the rise in this country.
Asthma has risen by 160 percent in children underage four since 1980, and the severity of the disease
among children has also increased.1
> 5% of Americans suffer from asthma
Almost 5 million children are affected
Asthma leads to ~ 5,000 deaths each year The frequency & severity of asthma attacks may be
increased by diesel exhaust, which acts as a respiratoryirritant, triggering responses in susceptible people.
1 Mannino DM, et al. Surveillance for asthma United States, 1960-1995.
Morbidity and Mortality Weekly Reports CDC Surveillance Summaries 47, 1998.
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Diesel & Asthma Continued
New research indicates that diesel exhaust may
actually cause allergies and asthma, rather thansimply aggravating pre-existing conditions.1
Diesel particles can worsen reactions to commonallergens such as pollen.2
Studies have shown that the proximity of a childs
school or home to major roads is linked toasthma, and decreased lung function, and theseverity of childrens asthmatic symptomsincreases with proximity to truck traffic.3
1 Diaz-Sanchez et al., J Allergy Clin Immunol 104, 1999:1183-1188.
2 Pandya et. al., Environ Health Perspectives 110(Suppl 1):103-112, 2002.
3 McConnell et al., Environ HealthPerspect 107, 1999: 1-9.
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Health Effects of NOx
NOx causes a wide variety of health & environmentalimpacts because of the many compounds & derivatives inthe family of nitrogen oxides, including:
Nitrogen dioxide, Nitric acid, Nitrous oxide, Nitrates, & Nitricoxide.
These compounds can react to form other toxicchemicals.
NOx causes respiratory problems; A recent Southern
California study showed that exposure can lead tosignificant decreases in lung function growth amongchildren.1
It is known to cause birth defects.
1 Gauderman et.al., Am. J. Resp. and Crit. Care Med., 162:1384-1390, 2000
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Adverse Environmental Impacts of NOx
It forms ozone smog, which can trigger seriousrespiratory problems.
It Contributes to many other environmentalproblems including:
Acid rain,
Nutrient overloading leading to water quality
problems,
Haze, and
Global warming.
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Diesel Exhaust: An Enormous Source to
Contend With
Though diesels only account for 2% of on-roadvehicles in California, they contribute to 30% ofNOx and 65% of particulates from the on-roadsector. (CARB, 2002)
While new diesels are much cleaner, older dirtierdiesels remain in use for decades, especially in
off-road applications.
For example, 16 large ocean-going ships typicallyrelease more smog-forming gases than 1 millioncars.
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Off-road equipment & vehicles are the dirtiest source of
diesel exhaust, followed closely by stationary generators.
The Dirtiest Diesel Sources
California Diesel Risk Reduction Plan, ARB, 2000
In California,
Heavy-duty Trucks, Construction & Farm Equipment, Marine
Vessels and Locomotives, together account for over 85% diesel PM
emissions
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Heavy-duty Diesel Emission
Testing & Research
Transit Buses: California Transit Bus Studies:
BP Arco
CARB
SF Muni
N.Y.S. Dept. of Environmental Conservation
Other Heavy-duty Vehicles:
Research in U.S. & Abroad
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California Transit Bus Studies
Test Buses: 40 Newflyer Buses, supplied by LAMTA
Detroit Diesel w/ market diesel & ox. cat. (BD)
w/ Low S diesel & PM trap (DPF)
Compressed Natural Gas, uncontrolled (CNG)
w/ox. cat.
Pollutants Tested:
Criteria: PM, NOx, CO + HCs
Toxics (ex. Benzene); Carbonyls (ex. Formaldehyde)
Semivolatiles, PAHs, and Nitro-PAHs
Mutagenicity
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Pollutant: CARB Study ARCO Study
NOx BD ~ DPF > CNG DPF > CNG
PM BD >> CNG > DPF DPF = CNG
THC/NMHC CNG >> BD > DPF CNG >> DPF
CO CNG > BD > DPF CNG >> DPF
Benzene CNG > BD > DPF1 CNG > DPF
Aldehydes CNG > DPF2 CNG >> DPF
PAH Species BD > CNG > DPF3 DPF ~ CNG
Nitro-PAHs DPF ~ CNG
Mutagenicity CNG >> BD ~ DPF4
NO2/NOx DPF >> BD ~ CNG
CO2 DPF ~ BD ~ CNG
CA Studies, Emissions from Highest to Lowest:
1 For combined BTEX
(Benzene, Toluene,
Ethylbenzene &Xylene)
2 Baseline Diesel
Samples were
invalidated
3 Excluding
naphthalene, due to
contamination of
sampling media4 This test appears to
have had problems
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Comparison of Recent Transit Bus Study
Emission Data, CBD Test Cycle
NOx (g/mile) PM (g/mile)
BD DPF CNG BD DPF CNG
CARB Study 30 31 19 0.12 0.01 0.04
BP-ARCO Study 40 35 16 0.66 0.01 0.01
NYC Study 26 27 24 0.22 0.04 0.02
M. Lev-On et. al., SAE 2002, Presented as Test - Tunnel Background & C. LeTavec et.al SAE
World Congress, March 4-7, 2002); Chatterjee et. al., Society of Automotive Engineers 2002-
01-0430; WMATA Alternative Fuels Workshop, July 6, 2000: NYCT CleanFuel Bus Programs.
BD = Baseline Diesel
DPF = Diesel with DPF
CNG = Compressed Natural Gas, no controls
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1) T. Beer et. al., Comparison of Transport Fuels, Final Report to the Australian Greenhouse Office, 2001.
2) Ayala et al. Draft: ARBs study of emissions from Late-model diesel and CNG heavy-duty transit buses.
3) Chatterjee et. al. SAE 2001.
4) Clark et. al., Diesel & CNG Transit Buses, 1999
5) Clark et.al. JAWMA; 52: 89-94. 2002.
6) GraggK. MTC 2001.
7) Lanni et al. SAE. 2001-01-0511.
8) LeTavec et al. Average Vehicle Test Results (School Buses, CSHVR Driving Cycle)
9) Lev-On M et al. SAE. 2002-01-0432.
10) London Bus Study, cited in: International Experience on Ultra Low Sulfur Diesel and Biodiesel, Micheal P. Walsh, January 2000.
11) P.J.E. Ahlvik and A.R.L. Brandberg, SAE paper # 2000-01-1882.
Heavy-Duty Vehicle PM Emissions, Various Grades of Diesel
Fuel
0.0
0.2
0.4
0.6
0.8
1.0
1.2
ULSD + Trap D: 10ppmS D: 50ppmS D: 500ppmS
PME
missions(g/mile
)
TruckTransit BusSchool Bus
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1) T. Beer et. al., Comparison of Transport Fuels, Final Report to the Australian Greenhouse Office, 2001.
2) Ayala et al. Draft: ARBs study of emissions from Late-model diesel and CNG heavy-duty transit buses.
3) Chatterjee et. al. SAE 2001.
4) Clark et. al., Diesel & CNG Transit Buses, 1999
5) Clark et.al. JAWMA; 52: 89-94. 2002.
6) GraggK. MTC 2001.
7) Lanni et al. SAE. 2001-01-0511.
8) LeTavec et al. Average Vehicle Test Results (School Buses, CSHVR Driving Cycle)
9) Lev-On M et al. SAE. 2002-01-0432.
10) London Bus Study, cited in: International Experience on Ultra Low Sulfur Diesel and Biodiesel, Micheal P. Walsh, January 2000.
11) P.J.E. Ahlvik and A.R.L. Brandberg, SAE paper # 2000-01-1882.
Heavy-Duty Vehicle PM Emissions,
Diesel Fuel with Aftertreatments
0.000
0.200
0.400
0.600
0.800
1.000
1.200
Low Sulfur Diesel +
DPF + EGR
ULSD + Trap ULSD + Cat Diesel + Cat D: 500ppmS
PME
missions(g/mile
Truck Transit Bus School Bus
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1) T. Beer et. al., Comparison of Transport Fuels, Final Report to the Australian Greenhouse Office, 2001.
2) Ayala et al. Draft: ARBs study of emissions from Late-model diesel and CNG heavy-duty transit buses.
3) Chatterjee et. al. SAE 2001.
4) Clark et. al., Diesel & CNG Transit Buses, 1999
5) Clark et.al. JAWMA; 52: 89-94. 2002.
6) GraggK. MTC 2001.
7) Lanni et al. SAE. 2001-01-0511.
8) LeTavec et al. Average Vehicle Test Results (School Buses, CSHVR Driving Cycle)
9) Lev-On M et al. SAE. 2002-01-0432.
10) London Bus Study, cited in: International Experience on Ultra Low Sulfur Diesel and Biodiesel, Micheal P. Walsh, January 2000.
11) P.J.E. Ahlvik and A.R.L. Brandberg, SAE paper # 2000-01-1882.
Heavy-Duty Vehicle PM Emissions,
Alternative Fuels
0.000
0.200
0.400
0.600
0.800
1.000
1.200
D: 500ppmS Biodiesel F-T F-T + DPF LPG (propane) CNG CNG + Cat LNG
PME
missions(g/mile
)
Truck Transit Bus School Bus
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1) T. Beer et. al., Comparison of Transport Fuels, Final Report to the Australian Greenhouse Office, 2001.
2) Ayala et al. Draft: ARBs study of emissions from Late-model diesel and CNG heavy-duty transit buses.
3) Chatterjee et. al. SAE 2001.
4) Clark et. al., Diesel & CNG Transit Buses, 1999
5) Clark et.al. JAWMA; 52: 89-94. 2002.
6) GraggK. MTC 2001.
7) Lanni et al. SAE. 2001-01-0511.
8) LeTavec et al. Average Vehicle Test Results (School Buses, CSHVR Driving Cycle)
9) Lev-On M et al. SAE. 2002-01-0432.
10) London Bus Study, cited in: International Experience on Ultra Low Sulfur Diesel and Biodiesel, Micheal P. Walsh, January 2000.
11) P.J.E. Ahlvik and A.R.L. Brandberg, SAE paper # 2000-01-1882.
Heavy-Duty Vehicle NOx Emissions,
Diesel Fuel with Aftertreatments
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
Low Sulfur Diesel +
DPF + EGR
ULSD + Trap ULSD + Cat Diesel + Cat D: 500ppmS
NOxEmissions(g/
mile)
Truck Transit Bus School Bus
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1) T. Beer et. al., Comparison of Transport Fuels, Final Report to the Australian Greenhouse Office, 2001.
2) Ayala et al. Draft: ARBs study of emissions from Late-model diesel and CNG heavy-duty transit buses.
3) Chatterjee et. al. SAE 2001.
4) Clark et. al., Diesel & CNG Transit Buses, 1999
5) Clark et.al. JAWMA; 52: 89-94. 2002.
6) GraggK. MTC 2001.
7) Lanni et al. SAE. 2001-01-0511.
8) LeTavec et al. Average Vehicle Test Results (School Buses, CSHVR Driving Cycle)
9) Lev-On M et al. SAE. 2002-01-0432.
10) London Bus Study, cited in: International Experience on Ultra Low Sulfur Diesel and Biodiesel, Micheal P. Walsh, January 2000.
11) P.J.E. Ahlvik and A.R.L. Brandberg, SAE paper # 2000-01-1882.
Heavy-Duty Vehicle NOx Emissions,
Alternative Fuels
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
D: 500ppmS Biodiesel F-T LNG CNG CNG + Cat LPG(propane)
NOxEmissions(g
/mile)
Truck Transit Bus
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Conclusions
Despite the large estimated reductions in diesel
PM, ARB predicts that over 250 excess cancer casesper million residents in California will still beattributable to diesel PM in 2020.
Children and other sensitive populations needspecial protection from the adverse health effectscaused by diesel exhaust.
Since exposure cannot be prevented, the sourcesthemselves diesel engines must be cleaned up.
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Final Conclusions The advances in diesel technology making new
vehicles much cleaner are very positive.
However, the NO2 & NOx increases from newtechnology still must be addressed.
If diesel vehicles and equipment cannot meetcurrent or future emissions standards, which aredesigned to protect public health, those enginesmust be phased out.
For older vehicles and equipment that will remainin use for many decades, here in the U.S. andabroad, the diesel industry must rise to thechallenge of developing clean-up technology.
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Diesel fuel is widely used throughout our society. It powers trucks that deliver products to ourcommunities, buses that carry us to school and work, agricultural equipment that plants and harvestsour food, and backup generators that can provide electricity during emergencies. It is also used formany other applications. Diesel engines have historically been more versatile and cheaper to runthan gasoline engines or other sources of power. Unfortunately, the exhaust from these enginescontains substances that can pose a risk to human health.
In 1998, the California Environmental Protection Agencys Office of Environmental Health Hazard
Assessment (OEHHA) completed a comprehensive health assessment of diesel exhaust. Thisassessment formed the basis for a decision by the California Air Resources Board (ARB) to formallyidentify particles in diesel exhaust as a toxic air contaminant that may pose a threat to human health.The American Lung Association of California (ALAC) and its 15 local associations work to preventlung disease and promote lung health. Since 1904, theAmerican Lung Association has been fighting lungdisease through education, community service, advocacyand research.
This fact sheet by OEHHA and ALAC providesinformation on health hazards associated with dieselexhaust.
What is diesel exhaust?What is diesel exhaust?What is diesel exhaust?What is diesel exhaust?
Diesel exhaust is produced when an engine burns diesel fuel. It is a complex mixture of thousands ofgases and fine particles (commonly known as soot) that contains more than 40 toxic aircontaminants. These include many known or suspected cancer-causing substances, such as benzene,arsenic and formaldehyde. It also contains other harmful pollutants, including nitrogen oxides(a component of urban smog).
How are people exposed to diesel exhaust?How are people exposed to diesel exhaust?How are people exposed to diesel exhaust?How are people exposed to diesel exhaust?
Diesel exhaust particles and gases are suspended in the air, so exposure to this pollutant occurswhenever a person breathes air that contains these substances. The prevalence of diesel-poweredengines makes it almost impossible to avoid exposure to diesel exhaust or its byproducts, regardlessof whether you live in a rural or urban setting. However, people living and working in urban andindustrial areas are more likely to be exposed to this pollutant. Those spending time on or near roadsand freeways, truck loading and unloading operations, operating diesel-powered machinery or
Diesel exhaustcontains more
than 40 toxic aircontaminants
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working near diesel equipment face exposure to higher levels of diesel exhaust and face higher healthrisks.
What are the health effects of diesel exhaust?What are the health effects of diesel exhaust?What are the health effects of diesel exhaust?What are the health effects of diesel exhaust?
As we breathe, the toxic gases and small particles of diesel exhaust are drawn into the lungs. Themicroscopic particles in diesel exhaust are less than one-fifth the thickness of a human hair and aresmall enough to penetrate deep into the lungs, where they contribute to a range of health problems.
Diesel exhaust and many individual substances contained init (including arsenic, benzene, formaldehyde and nickel)have the potential to contribute to mutations in cells thatcan lead to cancer. In fact, long-term exposure to dieselexhaust particles poses the highest cancer risk of any toxicair contaminant evaluated by OEHHA. ARB estimates thatabout 70 percent of the cancer risk that the average
Californian faces from breathing toxic air pollutants stems from diesel exhaust particles.
In its comprehensive assessment of diesel exhaust, OEHHA analyzed more than 30 studies of peoplewho worked around diesel equipment, including truck drivers, railroad workers and equipmentoperators. The studies showed these workers were more likely to develop lung cancer than workerswho were not exposed to diesel emissions. These studies provide strong evidence that long-termoccupational exposure to diesel exhaust increases the risk of lung cancer. Using information fromOEHHAs assessment, ARB estimates that diesel-particle levels measured in Californias air in 2000could cause 540 excess cancers (beyond what would occur if there were no diesel particles in theair) in a population of 1 million people over a 70-year lifetime. Other researchers and scientificorganizations, including the National Institute for Occupational Safety and Health, have calculatedcancer risks from diesel exhaust that are similar to those developed by OEHHA and ARB.
Exposure to diesel exhaust can have immediate health effects. Diesel exhaust can irritate the eyes,nose, throat and lungs, and it can cause coughs, headaches, light-headedness and nausea. In studies
with human volunteers, diesel exhaust particles made peoplewith allergies more susceptible to the materials to which theyare allergic, such as dust and pollen. Exposure to dieselexhaust also causes inflammation in the lungs, which mayaggravate chronic respiratory symptoms and increase thefrequency or intensity of asthma attacks.
Diesel engines are a major source of fine-particle pollution.
The elderly and people with emphysema, asthma, and chronic heart and lung disease are especiallysensitive to fine-particle pollution. Numerous studies have linked elevated particle levels in the air toincreased hospital admissions, emergency room visits, asthma attacks and premature deaths amongthose suffering from respiratory problems. Because childrens lungs and respiratory systems are stilldeveloping, they are also more susceptible than healthy adults to fine particles. Exposure to fineparticles is associated with increased frequency of childhood illnesses and can also reduce lungfunction in children.
Diesel exhaustincreases the risk of
cancer
And it can causecoughs and
aggravate asthma
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Diesel exhaustcontributes to smog
and fine-particlepollution
Like all fuel-burning equipment, diesel engines produce nitrogen oxides, a common air pollutant inCalifornia. Nitrogen oxides can damage lung tissue, lower the bodys resistance to respiratoryinfection and worsen chronic lung diseases, such as asthma. They also react with other pollutants inthe atmosphere to form ozone, a major component of smog.
What is being done to reduce the health risks from diesel exhaust?What is being done to reduce the health risks from diesel exhaust?What is being done to reduce the health risks from diesel exhaust?What is being done to reduce the health risks from diesel exhaust?
Improvements to diesel fuel and diesel engines have already reduced emissions of some of thepollutants associated with diesel exhaust. However, diesel exhaust is still one of the most widespreadand toxic substances in Californias air.
ARBs Diesel Risk Reduction Plan, when fully implemented,will result in a 75 percent reduction in particle emissions fromdiesel equipment by 2010 (compared to 2000 levels), and an85 percent reduction by 2020. The plan calls for the use ofcleaner-burning diesel fuel, retrofitting of existing engines with
particle-trapping filters, and the use in new diesel engines ofadvanced technologies that produce nearly 90 percent fewerparticle emissions, as well as the use of alternative fuels.
The use of other fuels, such as natural gas, propane andelectricity offer alternatives to diesel fuel. All of them produce fewer polluting emissions thancurrent formulations of diesel fuel. As a result of ARB and local air-quality regulations, public transitagencies throughout California are using increasing numbers of passenger buses that operate withalternative fuels or retrofitted equipment.
For further informationFor further informationFor further informationFor further information
Office of Environmental Health Hazard AssessmentOffice of Environmental Health Hazard AssessmentOffice of Environmental Health Hazard AssessmentOffice of Environmental Health Hazard Assessment1001 I Street, P.O. Box 4010, Sacramento, CA 95812-4010(916) 324-7572www.oehha.ca.gov
Air Resources BoardAir Resources BoardAir Resources BoardAir Resources Board1001 I Street, Sacramento, CA 95814(800) 363-7664www.arb.ca.gov
American Lung Association of CaliforniaAmerican Lung Association of CaliforniaAmerican Lung Association of CaliforniaAmerican Lung Association of California921 11th Street, Suite 700, Sacramento, CA 95814(916) 442-4446For your local office, call (800) LUNG-USAwww.californialung.org
The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. For a list ofsimple ways you can reduce demand and cut your energy costs, see OEHHAs web site atwww.oehha.ca.gov/public_info.html.
http://www.arb.ca.gov/http://www.californialung.org/http://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.californialung.org/http://www.arb.ca.gov/8/2/2019 RTD Presentation
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PROJECT GOALS
This project was part of the U.S. Department of Energys (DOEs)
reedomCAR and Vehicle Technologies (FCVT) Program. Onef the goals of the FCVT Program is to develop and deploy
dvanced transportation technologies that reduce the nations
use of imported oil and improve air quality. The goal of this
project was to demonstrate the emission performance of
natural gas transit buses. The project was performed in coop-
ration with DOEs Clean Cities Program, which supports
partnerships that deploy clean-burning alternative fuel
ehicles and build associated fueling infrastructure.
WMATAS NEED FOR CLEANER BUSES
The Washington Metropolitan Area Transit Authority (WMATA)
erves the public transportation needs of metropolitanWashington, DC, including Northern Virginia and Southern
Maryland. More than 1.7 million commuters ride WMATAs
ail cars and buses daily, and many of the areas tourists
ide the system as well. WMATA serves 348 bus routes with
,433 buses, including 164 that run on compressed natural
as (CNG, Figure 1).
The Washington, DC metropolitan area has air quality chal-
enges. The U.S. Environmental Protection Agency (EPA) clas-
ifies it as a severe ozone nonattainment area, even though
here are no significant stationary sources of air pollution.
The air pollution is primarily due to motor vehicle emissions.
To help alleviate this air pollution, the Washington, DC
City Council, the WMATA Board of Directors, and WMAT
officials developed a plan in 2001 to convert much of the
WMATA bus fleet from diesel to CNG. Under this plan,
WMATA will purchase CNG buses and modify fueling and
maintenance facilities to accommodate CNG buses, whene
reasonably possible (subject to ongoing vehicle availabilityand funding).
EMISSION TESTING OF WMATAS CNG BUSES
The Clean Cities Program worked closely with WMATA d
ing the CNG planning process, and DOE is interested in t
effects of the conversion to CNG buses, including real-wor
emission performance. In July 2002, DOE and its National
Renewable Energy Laboratory (NREL) evaluated the emissi
of new WMATA CNG buses and comparable diesel buses u
a heavy-duty chassis dynamometer.
Test VehiclesFive CNG and four diesel buses were randomly selected fro
the fleet of available buses. Of the four diesel buses, two h
low mileage (2,290 and 5,000 miles) and two had more th
100,000 miles. This difference in mileage had a negligible
effect on test results; emissions data from the low-mileage
high-mileage diesel buses were similar. All of the natural g
buses had between 1,900 and 2,600 miles. Test vehicle spe
cations are shown in Table 1.
Figure 1. Natural gas transit buses at WMATAs Bladensburg fueling facility. WM
operates 164 CNG-powered buses to reduce air pollution in the Washington
metropolitan area. Leslie Eudy, NREL/PIX
Evaluating the Emission Reduction Benefits oWMATA Natural Gas BusesPROJECT IMPACT
This project demonstrated the emission reduction performance
of natural gas transit buses versus conventional diesel counterparts:
the natural gas buses had 53% lower oxides of nitrogen (NOx),
85% lower total particulate matter (TPM), and 89% lower
carbon monoxide (CO). It is anticipated that these advantages
will encourage more extensive use of natural gas buses in U.S.
cities as transit agencies seek ways to meet stricter emissionmandates. Full replacement of conventionally fueled U.S. transit
buses with natural gas buses could
displace the equivalent of more than
600 million gallons of petroleum-
based fuels annually and result in
substantial air quality benefits.
Advantages of WMATAnatural gas transit buses:
53% lower NOx
85% lower TPM
89% lower CO
http://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.htmlhttp://www.oehha.ca.gov/public_info.html8/2/2019 RTD Presentation
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The CNG vehicles tested were model year 2001, 40-foot, low-
loor New Flyer buses. They were equipped with Cummins
Westport 8.3-L C-Gas Plus CNG engines and an oxidation
catalyst.
The diesel vehicles tested were model year 2000, 40-foot,
ow-floor Orion buses. They were equipped with Detroit
Diesel Series 50 engines and an oxidation catalyst, and they
used diesel fuel with a sulfur content of approximately
19 parts per million.
Test Equipment and Procedures
The vehicles were tested at WMATAs facility in Landover, MD
on West Virginia Universitys Transportable Heavy-Duty
Vehicle Emission Testing Laboratory. The laboratory is unique-
y configured using driveshafts to connect each drive axle to
ndividual dynamometers to avoid tire slippage experienced
on the more typically used dynamometer rolls. Exhaust gasesare collected and analyzed on site to determine regulated
emission rates using instruments made by Rosemount
Analytical and Varian.
The emission testing laboratory can be programmed with
various driving cycles to simulate different types of vehicle
operation. The driver matches the vehicles operation to the
peed and acceleration of the programmed test cycle using
a display inside the vehicle. For the WMATA testing, the
Central Business District (CBD) cycle was used, which simu-
ates the stop-and-go operation of transit buses being oper-
ated in congested urban areas.
Each test bus was run, without stopping, through four con
secutive CBD cycles on the dynamometer. The first cycle w
a warm-up cycle; the cumulative emissions from the final
three cycles were collected and measured. Measured emiss
included total hydrocarbons (THC), non-methane hydroca
bons (NMHC), CO, carbon dioxide (CO2), NOx, and TPM.
Results and Conclusions
Figure 2 shows the emission results for the CNG and dieselbuses. On average, the CNG buses reduced emission of NOx53%, TPM by 85%, and CO by 89% compared with the dies
buses. Overall, the Cummins Westport 8.3-L C-Gas Plus en
reduced these measured emissions significantly in this tran
bus application compared with model year 2000 diesel buse
NEXT STEPS
During the 2003 model year, WMATA will re-power someof its older diesel buses to incorporate new diesel engines
equipped with exhaust gas recirculation designed to meet
October 2002 requirements of the EPA Diesel Engine Cons
Decree. NREL will use this unique opportunity to evaluate
the emissions performance of the latest diesel engines com
pared with the latest CNG engines in transit buses.
Because of the interest in California and nationwide to con
sider regulating currently unregulated emissions, NREL als
plans to measure toxic emissions such as 1,3-butadiene an
benzene from CNG and diesel WMATA buses. The regulate
and unregulated emission testing is planned for 2003.
OR FURTHER INFORMATION, CONTACT
REL Alternative Fuels Team
Margo Melendezational Renewable Energy Laboratory617 Cole Blvd., MS 1633olden, CO 80401hone: 303-275-4479
ax: 303-275-4415-mail: [email protected] Printed with a renewable-source ink on paper containing at least
50% wastepaper, including 20% postconsumer waste.
either the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the acompleteness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any sommercial product, process, or ser vice by trade name, trademark, manufact urer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Uniteovernment or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect t hose of the United States government or any agency thereof.
Sponsored by the
www.eere.energy.gov
A Strong Energy Portfolio for a Strong AmericaEnergy efficiency and clean, renewable energy will mean a stronger eca cleaner environment, and greater energy independence for Americaing with a wide array of state, community, industry, and university pthe U.S. Department of Energys Office of Energy Efficiency and RenEnergy invests in a diverse portfolio of energy technologies.
Figure 2. Average chassis dynamometer emissions of natural gas and
diesel buses.
Produced by the
National Renewable Energy Laboratory (NREL)
NREL is a U.S. Department of Energy National Laboratory
Operated by Midwest Research Institute Battelle Bechtel
NREL/FS-540-33280 June 2003
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Engine, Bus and Truck ManufacturersOrganization Description
Blue Bird CorporationBlue Bird Corporation manufactures and markets a full product line of
school, transit, and shuttle buses. Special options are available on manyvehicles, including engines that can be fueled with either CNG or LNG.
CaterpillarCaterpillar is the world's largest manufacturer of construction and mining
equipment, diesel and natural gas engines, and industrial gas turbines.Chance Coach
Chance Coach offers a complete line of transit buses and trolleys, includingCNG and LPG-powered models.
Clean Air Power
Through its partnership with Caterpillar, Inc., Clean Air Power has been
providing conversion kits for a full-range of Caterpillar engines and fitting
standard engines with Dual-Fuel electronic controls since 1996. Its low-emissions vehicle systems are ideal for heavy-duty fleet owners, equipment
rental companies and engine manufacturers that need to reduce emissions of
their diesel vehicles in order to comply with federal and state regulations, aswell as display a responsible corporate and community image.
Cummins
Cummins is the world's largest designer and manufacturer of diesel engines
ranging from 55 to 3,500 horsepower. The key markets for these engines areon-highway vehicles, industrial equipment, and power generation. Cummins
is also a leader in the development and manufacturing of heavy-duty natural
gas engines.
Cummins Toughest
Standards
Cummins Toughest Standards site is designed to provide customers with keyinformation about the company's on-highway engine product line, which will
meet October 2002 EPA emission standards.
Cummins/Westport Natural
Gas Engines
Cummins Inc. and Westport Innovations Inc. formed a joint partnership todevelop, manufacture, and market low-emission, high-performance,
alternative fuel engines. The partnership has produced a new product line of
heavy-duty natural gas and propane engines for use in buses, trucks, and all
types of other regional/urban vocational vehicles.
Detroit Diesel Corporation
(DDC)
DDC, a subsidiary of DaimlerChrysler AG, designs, manufactures, and
services heavy-duty diesel and alternative fuel engines. The company offers a
complete line of engines from 22 to 10,000 horsepower for marine, military,construction, industrial, generator-set, mining, trucking, and automotive
markets.
Electric Fuel
Transportation Corporation
Electric Fuel Transportation Corporation designs, manufactures, and marketszero-emission, zinc-air, fuel cell electric buses for transit and school bus
applications.
Freightliner TrucksFreightliner Trucks is one of North America's leading manufacturers of
medium- and heavy-duty diesel trucks and specialized chassis.
GilligThe only heavy duty bus manufacturer in North American that does not
manufacturer heavy duty natural gas buses
GMC Commercial
Medium-Duty
General Motors offers a full product line of medium-duty commercial trucks
for all applications.
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International Truck and
Engine's Green DieselTechnology
This site promotes the International Truck and Engine Corporation's GreenDiesel Technology, which uses a combination of a catalyzed particulate filter,
low sulfur diesel fuel, and a specialized engine design to lower emissions and
odors from heavy-duty buses and trucks.
John Deere
John Deere is one of the world's leading manufacturers of agricultural,
construction, forestry, and lawn and turf care equipment. The company alsomanufactures diesel engines and other powertrain components for on- and
off-highway applications.
John Deere Natural Gas
Engines
John Deere CNG engines are designed for use in school buses, shuttle/transit
buses, and other on-highway applications.
Kenworth Kenworth is a manufacturer of custom heavy-duty trucks and chassis.
Mack Truck
Mack Truck is one of North America's larges manufacturers of heavy-duty
diesel trucks. Mack also offers a product line of heavy-duty vehicles capable
of operating on CNG and LNG.
NABI NABI is a manufacturer of heavy-duty buses for all urban transit applications.
Navistar InternationalCorporation
Navistar International Corporation is the parent company of International
Truck and Engine Corporation, a leading producer of mid-range dieselengines, medium trucks, school buses, heavy trucks, severe service vehicles,and parts and service sold under the International brand.
Neoplan USANeoplan USA is a manufacturer of standard and low floor transit buses,
articulated units, suburban models, and luxury coaches. Neoplan USA offers
a variety of buses with CNG and LNG engines.
New FlyerNew Flyer is the largest transit bus manufacturer in North America. It offers a
full line of transit and shuttle buses and alternative fuel buses that run onCNG, LNG, and hybrid electric diesel buses.
Nova BUS CorporationNova BUS Corporation is a leader in the design, production, and marketing of
urban transit buses. Nova BUS products include CNG and LNG models.
Orion Bus Industries
Orion Bus Industries manufactures heavy-duty transit buses to meet all urbantransit applications, including full sized passenger buses, low-floor models,
and shuttles. Orion offers a broad array of engine choices and is a leader in
alternative fuel technology.
PACCARPACCAR manufactures heavy-duty on- and off-road Class 8 trucks sold
around the world under the Kenworth, Peterbilt, DAF, and Foden nameplates.
Peterbilt
With a full line of Class 6-8 trucks, Peterbilt is a leading producer of heavyvehicles used by the commercial trucking and construction industries.
Peterbilt's line of trucks includes dual fuel models powered by a combination
of diesel and natural gas.
Propane School Bus.com
This site was developed by the Propane Promotional Consortium and thePropane Education and Research Council to promote the purchase of low-
emission, alternative fuel school buses capable of running on liquefied
petroleum gas (LPG).
Sterling Trucks
Sterling, a daughter company of Freightliner, LLC, manufactures and markets
vocationally oriented Class 5-8 heavy and medium-duty trucks under the
brands of Sterling and Western Star Trucks. Company products target specific
market applications in the construction, distribution, and urban services
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