Gaseous Fuels in Transportation -- Prospects and Promise

OHVT MissionTo conduct, in collaboration with our heavy vehicle industry partners and their suppliers,

a customer-focused national program to research and develop technologies that will enable trucks and other heavy vehicles to be more energy efficient and able to use

alternative fuels while simultaneously reducing emissions.

Presented at theGas Storage Workshop

Kingston, Ontario, CanadaJuly 11-12, 2001

Gaseous Fuels in Transportation --Prospects and Promise

Dr. James J. Eberhardt, DirectorOffice of Heavy Vehicle Technologies

U.S. Department of Energy

Office of Heavy Vehicle Technologies

The Transportation Energy SituationTransportation Options for the 21st CenturyFuture of Combustion Engines in TransportationNatural Gas As Alternative FuelTwo-Pronged Fuels StrategyHydrogen As Alternative FuelSummary

Outline

Gaseous Fuels in Transportation --Prospects and Promise


Rationale for a Heavy Vehicle Technologies R&D Program

Since the 1973 Oil Embargo All of the Increase in U.S. Surface Transportation Fuel Consumption has been due to Heavy Vehicles

0

2

4

6

8

10

12

14

16

1970 1980 1990 2000 2010 2020Ener

gy U

se -

Mill

ion

Bar

rels

per

Day

Class 3-8 Trucks

Class 1-2 Trucks(Pickups, Vans, SUVs)

Automobiles

Projected

Sources: EIA Annual Energy Outlook 2000, DOE/EIA-0383(2000), December 1999Transportation Energy Data Book: Edition 20, DOE/ORNL-6959, October 2000

Railroad Marine

Off-Highway

Actual


The Transportation Sector Is Almost Totally Dependent on Liquid Carbon-Based Fuels

97%

2.8%

0.2%

Transportation Energy Consumption, 1997

Source: DOE/EIA Monthly Energy Review; July 1998

Electricity

Natural Gas

Petroleum

Creating Transportation

Options for the 21st

Century


1960s Steam (Rankine cycle) engines

1970s Gas turbines Stirling engines

1980s Adiabatic engines Alternative fuels

1990s Hybrids Fuel cells

Transportation Energy Conversion Technology R&D

History of “Promising” Alternatives


Less than $5M in a given year Greater than $5M in a given year • Program Terminated

1970 1975 1980 1985 1995 20001990

• Rankine Cycle Engine ($24M)

Automotive Gas Turbine ($393M)

EV Battery (>$410M)

Fuel Cell (>$150M)

Hybrid (>$220M)

• Automotive Stirling ($142M)

•

Transportation Energy Conversion Technology R&D


Alternatives to Carbon-based Fuels

-3000-2500-2000-1500-1000-500

0Hy

drog

en

Met

hane

Etha

ne

Prop

ane

Buta

ne

Pent

ane

Hexa

ne

Oct

ane

Nona

ne

Ceta

ne

Enthalpy of Combustion (kcal/mol)

As a chemical storage system, we have no practical substitute for the C-C bond.

Gas LiquidRoom Temp Transition


Energy Density of Fuels

1058990

922

683635

594

488

270 266

6814

0

200

400

600

800

1,000

1,200

Diesel Gasoline LNG Methanol CompressedHydrogen(@ 3626 psi)

Diesel Fuel LNG CNG(@ 3626 psi)

Compressed Hydrogen(@ 3626 psi)

Liquid H2MethanolF-TDiesel

Gasoline Ethanol

Thou

sand

Btu

per

ft3

NiMHBattery

Propane


0% 10% 20% 30% 40% 50% 70%

Conventional ICE

Compression-Igniton,

Fuel Cell-Stored Hydrogen

Today's Capability

Projected Capability(2004)

Peak Thermal Efficiency (%)

Fuel Cell-Methanol Reformer

Fuel Cell-Stored Hydrogen

Compression-Ignition Direct-Injection ICE

Gas Turbine

Conventional Spark Ignition ICE

Heavy Duty Diesel Engine

60%

Gasoline Direct Injection

Comparison of Energy Conversion Efficiencies


Vehicle Range Limitation -Challenge To Be Overcome By Alternatives

0 20 40 60 80 100

Comparison of Miles Driven (Same Volume of On-Board Fuel)

Diesel Engine-Conv. Diesel Fuel

Diesel Engine-F-T Diesel

Direct Injection Engine- GasolineAdv. NG Engine-CNG (3,600 psi)

Fuel Cell-Hydrogen (3,600 psi)

Fuel Cell - Gasoline

Office of Heavy Vehicle TechnologiesCreating Transportation Options for the 21st Century

Combustion Engines Are Still the Most Viable for Future

Heavy Vehicles


Increasing Efficiency

Decreasing Emissions

Source: Cummins, modified by DOE

THER

MA

L EF

FIC

IEN

CY

(%)

Source: Caterpillar

1930 1940 1950 1960 1970 1980 1990 2000

0.25

0.3

0.35

0.4

0.45

YEAR

PRODUCTION

RESEARCH

30

35

40

4550

55

Efficiency objective reached with DOE assisted R&D

BSF

C (L

B /

HP

-HR

)

ConsentDecree

YEAR

NO

x (g

m/h

p-hr

)

Part

icul

ates

(gm

/hp-

hr)

1987 Models

1988 Models

1991 Models1994 Models

EPA 2007

EPA/CARB 2004 (SOP)

1980 1990 20000

2

4

6

8

10

12

14

16 1.5

1.0

0.5

NOx

Particulates

ConsentDecree

Heavy-Duty Diesel Engine Progress

Diesel Engines Continue To Be The Most Viable Option for Heavy Vehicles


Progress in Reducing Diesel Emissions

Integrated systems approachProgress made in all 3 areasPartnerships with leading industry suppliers, truck/auto manufacturing, energy companies, and national labsCross-cutting applications

Fuels

Emission Controls

Engine Combustion

Auto Light Truck Heavy Truck


Laboratory Demonstrated Diesel Emissions –Tier 2 Results

Particulates (g/mi)

NO

x(g

/mi)

5,500 lb vehicleNOx Adsorber then Soot filterDiesel fuel reductant (< 5%)10.4 km per liter(24.4 mpg) city

0.0

0.2

0.4

0.6

0.00 0.02 0.04 0.06 0.08

Laboratory Setup:• Stationary engine control system• Stationary aftertreatment system• Urban Dyno Drive Schedule (UDDS) – First 1,392 secs. of FTP• Sulfur < 4 ppm, 48 Cetane• NOx accuracy +/- 0.025 g/mi• PM accuracy +/- 0.005 g/mi

Source: Cummins


Natural Gas Vehicles

Current natural gas engines can have very low engine-out emissions compared to current model diesels.Customers are seeking better fuel economy, higher power ratings, and lower capital expenditures.Ultra-low NOx emissions (<0.2 g/bhp-hr) will be needed to meet future regulations and to compete with emerging clean diesel technology.Efficiency may continue to be a barrier along with on vehicle storage.Recent price increases for natural gas create uncertainty for vehicle operators.Use of natural gas for power generation competes with use for vehicles.

Pros and Cons


Natural Gas as Fuel for Heavy Vehicles

Current natural gas engines operate at lower efficiency than conventional engines.On-board fuel storage for natural gas too expensive, too heavy and inconvenient for operators to refill.Natural gas transportation fuel facilities not widely available.Fueling facilities for natural gas are too expensive.

Technology Barriers


EPA Emissions Standards

February 10, 2000 EPA adopted Tier 2 Emissions Standards which became effective April 10, 2000. (Includes reducing sulfur levels in gasoline to 30 ppm.)December 2000 EPA adopted heavy-duty diesel engine emissions standards to be phased in 2007-2010.January 18, 2001 EPA issued rule requiring 80 percent of all on-road diesel fuel to have less than 15 ppm sulfur starting in 2006.


EPA Emissions Standards

Tier 2 Regulations for Light-Duty Vehicles (LDVs):0.07 g/mi NOx and 0.01 g/mi PM; represent 77 to 95% reduction from Tier 1 levelsIncludes all LDVs under 10,000 lbsPhased in 2004-2008

Heavy-Duty Diesel Engine Regulations:0.2 g/bhp-hr NOx and 0.01 g/bhp-hr PM; represents about 90% reduction from 2004 regsPhased in 2007-2010

Heavy-duty regulations include ultra-low sulfur diesel fuel


New Emissions StandardsIntroduce New Challenges

Impact of EPA 2007 emissions standards0.2 g/bhp-hr NOx will be difficult to achieve with natural gas as well as dieselOther regulated emissions also toughProgress in emissions control technologies R&D indicates diesel engines are likely to meet standards

Emissions advantage of natural gas is diminishing.


Homogeneous Charge Compression Ignition (HCCI) Engines

- 6°

+ 4°

+ 10°

Potential of HCCI EnginesHigh efficiencyVery low NOxLower cost (possibly no need for high pressure injection system, 1/3rd of diesel engine cost)Low cycle-to-cycle variationFuel flexibilityUnthrottled operation

Spark ignition HCCIRecent HCCI experiments by HondaNatural gas may be a good

fuel choice for HCCI.

Technical challenges of HCCIDifficult to controlDifficult to startHigh peak heat release and peak pressureHigh hydrocarbon and CO emissions

On-Board Gas Storage –

The Subject of This Workshop


Current and projected pressures (3,600 psito 10,000 psi) are inconvenient and potentially very hazardous.

Challenges

On-Board Natural Gas Storage

Heavy and strong tanks are required.Multistage compression is required and very expensive.


Breakthrough Enables Two-Pronged Fuels Strategy

Clean, High Efficiency Compression Ignition

Engines (Diesel or Homogeneous Charge)

Liquid Fuels for All Heavy Vehicles

Gaseous Fuels for Light and

Medium Trucks


HYDROGENHYDROGEN

Hydrogen can be stored on board and supplied directly to the fuel cell:

Strategy for Fuel Cell Vehicles

HydrocarbonHydrocarbonFuelFuel

H2- RichGas

FUELFUELCELLCELL

Hydrogen can be derived on-board from fuels such as ethanol, methanol, natural gas, gasoline or FT fuels:

Storage (volume, pressure, weight) and Infrastructure Issues

Complexity, Cost, & Start-up Issues

FUEL FLEXIBLEFUEL FLEXIBLEFUEL FUEL

PROCESSORPROCESSOR

Hydrogen As Alternative Fuel


Hydrogen ProductionLas Vegas, NV Station - autothermal reformer/steam methane reformerPalm Desert Station, CA - autothermal reformer

advanced cyclic reformerelectrolyzers

Chula Vista, CA Station – steam methane reformer

StoragePressurized Tanks – 5,000 to 10,000psiCryogas Tank - private auto company vehicle

Vehicles30% Hydrogen/70% Natural Gas Mixture

Hydrogen Infrastructure


TomorrowToday

Compressed Storage Tanks

Cryogenic Liquid HydrogenMetal Hydrides and Carbon-nanotubes?

Hydrogen Storage


The transportation sector is almost totally dependent on liquid carbon-based fuels.Combustion engines are still the most viable transportation energy conversion technologies for the near future despite a history of R&D on “promising” alternatives.Vehicle range limitation is one challenge that needs to be overcome by alternatives, especially gaseous fuels.EPA enacted emissions regulations that include ultra-low sulfur fuel requirements have diminished the emissions advantage of gaseous fuels burned in internal combustion engines. Research results show that ultra-low sulfur fuel will enable diesel engines to meet stringent emissions standards.Breakthroughs are needed in on-board storage and engine efficiency (e.g., HCCI) to improve prospects for gaseous fuels as alternatives to liquid carbon-based fuels for transportation.

Summary

Gaseous Fuels in Transportation -- Prospects and Promise

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