Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use (2010)

Chapter: Appendix D: Description of GREET and Mobile6 Models and Their Applications

« Previous: Appendix C: Description of the Air Pollution Emission Experiments and Policy (APEEP) Model and Its Application
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

D
Description of GREET and Mobile6 Models and Their Applications

BACKGROUND

The Need for Emissions Data in the National Research Council Study

To evaluate the per vehicle miles traveled (VMT) total damages from transportation, the APEEP1 county emission-unit-damage costs must be evaluated against vehicle emissions. Although the passenger and freight fleets are diverse, particular vehicle and fuel combinations dominated in 2005, and certain vehicles and fuels are of particular interest for 2030. It is important to acknowledge life-cycle considerations related to both the vehicles and the fuels. In particular, feedstock production, fuel production, and vehicle manufacturing could have significant emissions contributions in the life-cycle inventory. The vehicle-fuel inventory should include these life-cycle components in addition to vehicle operation.

Available Options for Constructing Emissions Estimates

Although tools and data are available to evaluate the many vehicle and fuel operational emissions, GREET2 stands as one of the few resources to evaluate life-cycle component emissions (Argonne National Laboratory 2009). The GREET life-cycle factors cover a range of light-duty vehicles and the fuels they consume. GREET evaluates the many processes involved from

1

Air Pollution Emission Experiments and Policy.

2

Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation.

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

feedstock production through vehicle operation. Without using GREET, individual process assessments throughout the supply chain would need to be performed and combined for each vehicle and fuel of interest.

EMISSIONS DATA AND MODELING

The GREET Model

The Argonne GREET model is used to determine emissions from light-duty autos and trucks. The GREET model is a vehicle operation and fuel production life-cycle assessment tool, which captures fuel feedstock production, fuel refining, vehicle operation, and vehicle manufacturing. Feedstock production, fuel refining, and vehicle operation are estimated with the GREET 1.8b model; vehicle manufacturing is determined with GREET 2.7a. The version designations (1.8b and 2.7a) do not imply different generations of GREET but distinguish between a version developed for the fuel cycle (1.8b) versus a version developed for the vehicle cycle (2.7). The strength of the GREET model lies in its ability to estimate a variety of fuel inputs and vehicle combinations and their associated well-to-wheel life-cycle components. GREET allows for specification of critical inputs to these components (for example, emission factors, combustion technologies, energy efficiencies, and fuel types).

GREET evaluates several life-cycle components for the feedstock production, fuel production, and vehicle-manufacturing emissions inventory. For the feedstock and fuel production cycle, GREET captures extraction and creation of raw feedstock, transport to refineries, refinery processes, and transport to fueling stations. These constitute the well-to-pump components. On the vehicle-cycle side, GREET performs a materials-based life-cycle assessment capturing raw material extraction, processing, transport, and ultimately assembly into an automobile or light-duty truck. GREET does not estimate heavy-duty vehicle life-cycle factors, so additional data sources were needed to evaluate these vehicle classes.

GREET allows for the adjustment of many feedstock, fuel, and vehicle operation input parameters; however, particular inputs were targeted for the vehicle and fuel combinations evaluated. The evaluation year was toggled for the 2005 and 2030 scenarios to capture changes in both vehicle operational performance as well as efficiency changes in other devices, such as engines and turbines. The fraction of crude oil that comes from tar sands and the amount of reformulated gasoline were adjusted on the basis of the vehicle and fuel combination. For ethanol, GREET inputs for feedstocks (corn, herbaceous, and corn stover) and milling processes (dry or wet) were changed. Another critical input parameter for the assessment is the fraction of low-sulfur diesel. Last, the electricity mix for 2005 and 2030 were ad-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

justed on the basis of the U.S. Energy Information Administration’s Annual Energy Outlook, which reports historical mixes as well as future forecasts (EIA 2006, 2009a).

Mobile6.2

To evaluate heavy-duty vehicle emissions, EPA’s Mobile6.2 on-road emissions modeling tool was used (EPA 2009). Unlike GREET, Mobile6.2 is designed to evaluate the many different conditions under which vehicles may operate, and not feedstock production, fuel production, or vehicle-manufacturing life-cycle emissions. Mobile6.2 heavy-duty vehicle operational emission factors were used in combination with GREET feedstock and fuel production factors to create life-cycle inventories for several different vehicle classes.

GREET does not evaluate ammonia emissions, so Mobile6.2 is used to capture this pollutant for both light- and heavy-duty vehicles. Ammonia emissions, which result in secondary particle formation, were determined by Mobile6.2 for a set of vehicles that overlap with the vehicle and fuel combinations evaluated in GREET. Ammonia emissions were estimated for the vehicle operation component only; they were not estimated for the feedstock, fuel, and vehicle manufacturing components.

THE EMISSIONS MODELING PROCESS

Model Framework

The emissions model utilized GREET to generate feedstock, fuel production, operation, and vehicle-manufacturing factors for light-duty vehicles and Mobile6.2 to generate operational factors for heavy-duty vehicles. GREET feedstock and fuel production factors were applied to the heavy-duty vehicle Mobile6.2 operational factors, as described later in this appendix. For all vehicles, energy inputs, CO2, CH4, N2O, VOC, CO, NOx, PM10, PM2.5, and SOx emissions are determined for the life-cycle components. APEEP county unit damages are based on emissions of VOCs, NOx, PM2.5, and SOx.

GREET Temporal Boundaries

GREET can evaluate vehicles and life-cycle processes from 1990 through 2020. The tool has many time series for engines, turbines, and critical parameters that capture changes in efficiencies, emissions, and other parameters (for example, ethanol yields from corn and fuel sulfur levels) historically and up to 2020. GREET also makes the assumption that fleet age is 5 years. When evaluating life-cycle emissions in a year, GREET as-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

sumes that vehicles are 5 years older and assigns them the corresponding emissions. When using GREET to evaluate vehicles in 2005, emissions from vehicles correspond to year 2000. However, all other values in GREET’s assessment (such as fuel sulfur levels or electricity mixes) correspond to 2005.

The 2030 assessment is outside the GREET temporal upper range, so 2020 is used as a baseline (although adjustments are made and described later in this section).

GREET Vehicle-Manufacturing Emissions

The GREET 2.7a model was used to determine vehicle-manufacturing emissions. The model performs a life-cycle assessment from vehicle material inputs to determine emissions from manufacturing for cars and SUVs. The model distinguishes between internal-combustion-engine vehicles, hybrid electric vehicles, and fuel-cell electric vehicles from both conventional and light-weight materials. The material inputs are evaluated for the body, powertrain system, transmission system, chassis, battery, fluids, paint, traction motor, generator, electronic controller, and fuel-cell auxiliary system. These components are assessed from material extraction through assembly, and emissions are determined at each stage. Disposal is included.

There is no time dependency with GREET’s vehicle-manufacturing assessment, so process changes from 2005 through 2030 are not captured. Energy and emission factors are determined for the vehicle size, powerdelivery systems, and material-composition combinations, as shown in Table D-1 and Table D-2.

The car conventional-material factors are used for all light-duty autos, and the SUV conventional-material factors are used for light-duty trucks class 1 and 2.

GREET Light-Duty Auto and Truck Energy and Emissions Factors

Light-duty automobile and truck life-cycle energy inputs and emissions are determined from GREET. GREET distinguishes between light-duty trucks class 1 and 2 to capture the increased energy requirements and resulting emissions of the larger vehicles. Class 1 trucks are between zero and 6,000 lb gross-vehicle-weight rating (GVWR) and less than 3,750 lb loaded vehicle weight (LVW), and class 2 trucks have the same GVWR and greater than 3,750 LVW. For each vehicle and fuel combination, GREET is used to determine feedstock, fuel, and operational factors for light-duty autos, trucks in class 1 (LDT1), and trucks in class 2 (LDT2).

GREET allows for the adjustment of many vehicle and fuel parameters; however, certain critical parameters are adjusted some of the vehicle and fuel combinations to estimate life-cycle emissions. For reformulated gaso-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-1 GREET 2.7a Vehicle-Manufacturing Results for Cars

 

ICEV: Conventional Material

ICEV: Light-Weight Material

HEV: Conventional Material

HEV: Light-Weight Material

FCV: Conventional Material

FCV: Light-Weight Material

Lifetime VMT

160,000

160,000

160,000

160,000

160,000

160,000

Total energy

633

619

645

669

792

797

Fossil fuels

592

573

600

618

732

735

Coal

223

164

235

190

264

218

Natural gas

243

226

243

241

308

298

Petroleum

126

183

122

187

160

219

CO2

47

46

50

50

62

60

CH4

0.082

0.077

0.083

0.083

0.102

0.099

N2O

0.001

0.001

0.001

0.001

0.001

0.001

GHGs

50

48

52

52

65

63

VOC

0.206

0.205

0.206

0.205

0.205

0.205

CO

0.250

0.093

0.226

0.098

0.217

0.089

NOx

0.075

0.080

0.077

0.085

0.094

0.099

PM10

0.082

0.066

0.080

0.071

0.092

0.081

PM2.5

0.033

0.028

0.031

0.029

0.036

0.033

SOx

0.137

0.147

0.228

0.213

0.286

0.259

TABLE D-2 GREET 2.7a Vehicle-Manufacturing Results for SUVs

 

ICEV: Conventional Material

ICEV: Light-Weight Material

HEV: Conventional Material

HEV: Light-Weight Material

FCV: Conventional Material

FCV: Light-Weight Material

Lifetime VMT

180,000

180,000

180,000

180,000

180,000

180,000

Total energy

730

728

840

833

1030

970

Fossil fuels

683

672

780

766

951

890

Coal

263

194

316

244

350

271

Natural gas

280

266

318

299

399

361

Petroleum

140

212

146

223

203

259

CO2

54

54

65

62

80

73

CH4

0.095

0.090

0.108

0.103

0.132

0.120

N2O

0.001

0.001

0.001

0.001

0.001

0.001

GHGs

57

56

68

65

84

76

VOC

0.308

0.307

0.308

0.307

0.308

0.307

CO

0.298

0.105

0.316

0.116

0.297

0.103

NOx

0.085

0.092

0.096

0.102

0.118

0.117

PM10

0.095

0.078

0.107

0.089

0.121

0.100

PM2.5

0.038

0.033

0.041

0.036

0.047

0.041

SOx

0.151

0.166

0.297

0.267

0.373

0.317

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

line vehicles, GREET’s share of reformulated gasoline in total gasoline factor was set to 100%. For conventional and reformulated gasoline vehicles using petroleum derived from tar sands oil, GREET’s share of oil sands products in crude oil refineries was set to 100%. GREET assumes that in 2005 an 80% share of dry mill corn ethanol production (this increases to 90% by 2020). In evaluating E10 and E85 fueled vehicles from corn ethanol feedstock, this percentage was adjusted. For E10 and E85 from dry corn this was set to 100% while from wet corn, to 0% (or 100% wet milling plants). To evaluate the compression ignition direct injection low-sulfur diesel combination, the share of low-sulfur diesel in total diesel use was specified as 100% for 2005. For the other vehicle and fuel combinations, default GREET values were left unchanged. The ethanol yield factors were verified against existing literature and electricity mixes for the two time periods received slight adjustments based on the U.S. Energy Information Administration’s Annual Energy Outlook. The energy and emission factors for the different vehicle types (LDA, LDT1, and LDT2) in 2005 are shown in Table D-3, Table D-4, and Table D-5 and for 2020 in Table D-6, Table D-7, and Table D-8.

2030 Fuel Economy and Emission-Factor Adjustments

The implementation of 35 miles per gallon fuel economy standards for 2030 requires an adjustment to GREET default 2020 emission factors. The GREET model assumes fuel economies between 20 and 30 miles per gallon for conventional gasoline and E85 light-duty automobiles in 2020. For light-duty trucks the fuel economy ranges are even lower (20-24 miles per gallon for LDT1 and 17-20 miles per gallon for LDT2). For 2030, all energy and emission factors are adjusted based on the GREET default fuel economies and the expected 35 miles per gallon standard. Fuel and feedstock factors from GREET are reduced by the percentage reduction of default and 35 mile per gallons economies (for example, if the 2020 fuel economy is specified as 24 miles per gallon then the fuel and feedstock emission factors for 2020 are multiplied by 24/35 to determine the adjusted 2030 factors). This is based on the assumption that with an increase in fuel economy, a proportional reduction is needed in fuel production, which results in lower feedstock requirements. Vehicle operation combustion factors are also reduced using the same methodology. VOC evaporative losses and PM tire and brake wear factors were left unchanged from GREET default values as well as vehicle manufacturing. Both automobiles and light-duty trucks were assessed the adjusted factors. Trucks show the largest changes from default to the 35 miles per gallon standard due to relatively low GREET estimated 2020 fuel economies. All vehicles that had fuel economies greater than 35 miles per gallon in GREET in 2020 were not adjusted.

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-3 GREET Energy and Emission Factors for Light-Duty Autos in 2005

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

Btu/VMT

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

232

64

6

18

0.02

0.15

0.01

0.05

Fuel

1241

457

72

77

0.13

0.17

0.02

0.11

Operation

5259

5038

404

408

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SI Autos (Tar Sands)

Feedstock

853

62

50

64

0.02

0.14

0.01

0.06

Fuel

1295

457

72

78

0.13

0.17

0.02

0.11

Operation

5259

5038

404

408

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CG SI Autos (Conventional Oil)

Feedstock

236

65

17

29

0.02

0.15

0.01

0.05

Fuel

1007

447

68

71

0.13

0.14

0.02

0.10

Operation

5334

5257

410

414

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CG SI Autos (Tar Sands)

Feedstock

865

63

62

76

0.02

0.14

0.01

0.06

Fuel

1059

447

68

72

0.13

0.14

0.02

0.10

Operation

5334

5257

410

414

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SIDI Autos (Conventional Oil)

Feedstock

202

55

5

16

0.02

0.13

0.00

0.05

Fuel

1080

397

62

67

0.12

0.15

0.02

0.10

Operation

4573

4381

351

355

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SIDI Autos (Tar Sands)

Feedstock

742

54

44

56

0.02

0.12

0.01

0.05

Fuel

1126

397

63

68

0.12

0.15

0.02

0.10

Operation

4573

4381

351

355

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

193

53

19

29

0.02

0.12

0.00

0.04

Fuel

613

309

46

48

0.02

0.09

0.01

0.07

Operation

4383

4383

347

350

0.09

0.30

0.07

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Diesel (Fischer Tropsch)

Feedstock

280

18

22

35

0.02

0.11

0.00

0.05

Fuel

2882

68

106

114

0.03

0.25

0.06

0.09

Operation

4383

0

334

338

0.09

0.30

0.07

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Diesel (Soy BD20)

Feedstock

427

213

−30

−13

0.03

0.23

0.01

0.13

Fuel

9433

14

12

5

0.28

−0.03

0.00

−0.06

Operation

4383

3555

344

348

0.09

0.30

0.07

0.04

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CNG

Feedstock

436

24

31

64

0.03

0.16

0.00

0.07

Fuel

415

20

35

36

0.00

0.05

0.01

0.12

Operation

5615

0

333

342

0.15

0.30

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Dry Corn)

Feedstock

822

229

−225

−173

0.06

0.42

0.02

0.19

Fuel

6277

345

72

82

0.26

0.50

0.05

0.18

Operation

5334

1412

402

406

0.22

0.30

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Wet Corn)

Feedstock

898

498

−212

−144

−0.14

0.58

0.03

0.29

Fuel

6386

201

221

233

0.25

0.41

0.12

0.40

Operation

5334

1412

402

406

0.22

0.30

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Herbaceous)

Feedstock

570

216

−282

−237

0.06

0.29

0.02

0.06

Fuel

4618

179

3

15

0.19

0.45

0.03

−0.02

Operation

5334

1412

402

406

0.22

0.30

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

Btu/VMT

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

407

229

−263

−261

0.03

0.24

0.02

0.11

Fuel

4206

179

3

14

0.19

0.43

0.03

−0.02

Operation

5334

1412

402

406

0.22

0.30

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Dry Corn)

Feedstock

287

79

1

17

0.02

0.17

0.01

0.06

Fuel

1343

430

66

69

0.13

0.16

0.02

0.11

Operation

5334

4990

409

413

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Wet Corn)

Feedstock

294

103

2

19

0.01

0.19

0.01

0.07

Fuel

1352

417

79

82

0.13

0.15

0.03

0.12

Operation

5334

4990

409

413

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

265

78

−4

11

0.02

0.16

0.01

0.05

Fuel

1197

416

60

63

0.13

0.15

0.02

0.09

Operation

5334

4990

409

413

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Corn Stover)

Feedstock

251

79

−2

9

0.02

0.16

0.01

0.06

Fuel

1161

416

60

63

0.13

0.15

0.02

0.09

Operation

5334

4990

409

413

0.23

0.30

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Electric

Feedstock

159

56

12

25

0.03

0.08

0.13

0.04

Fuel

2734

81

380

381

0.01

0.53

0.02

1.31

Operation

1778

84

0

0

0.00

0.00

0.01

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

180

10

13

27

0.01

0.07

0.00

0.03

Fuel

1539

29

243

250

0.01

0.14

0.04

0.16

Operation

2319

0

0

0

0.00

0.00

0.01

0.00

Vehicle

792

160

62

65

0.21

0.09

0.04

0.29

Grid-Independent SI HEV

Feedstock

159

44

11

20

0.01

0.10

0.00

0.04

Fuel

680

302

46

48

0.09

0.10

0.01

0.07

Operation

3604

3552

277

281

0.16

0.25

0.02

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Grid-Dependent SI HEV

Feedstock

159

48

12

21

0.02

0.09

0.04

0.04

Fuel

1358

229

156

158

0.06

0.24

0.01

0.48

Operation

3002

2408

185

188

0.10

0.17

0.01

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-4 GREET Energy and Emission Factors for Light-Duty Trucks 1 in 2005

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

Btu/VMT

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

297

82

7

23

0.02

0.19

0.01

0.07

Fuel

1587

584

92

98

0.17

0.22

0.03

0.15

Operation

6722

6439

516

520

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SI Autos (Tar Sands)

Feedstock

1090

79

65

82

0.03

0.18

0.01

0.08

Fuel

1655

584

93

99

0.17

0.22

0.03

0.15

Operation

6722

6439

516

520

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Conventional Oil)

Feedstock

301

83

22

37

0.02

0.19

0.01

0.07

Fuel

1287

572

87

91

0.16

0.18

0.02

0.13

Operation

6818

6719

524

528

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Tar Sands)

Feedstock

1106

80

80

97

0.03

0.18

0.01

0.08

Fuel

1353

572

87

92

0.16

0.18

0.02

0.13

Operation

6818

6719

524

528

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Conventional Oil)

Feedstock

258

71

6

20

0.02

0.16

0.01

0.06

Fuel

1380

508

80

86

0.15

0.19

0.02

0.13

Operation

5845

5599

449

453

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Tar Sands)

Feedstock

948

69

56

71

0.02

0.16

0.01

0.07

Fuel

1439

508

80

86

0.15

0.19

0.02

0.13

Operation

5845

5599

449

453

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

247

68

24

37

0.02

0.15

0.01

0.06

Fuel

783

394

59

61

0.02

0.12

0.02

0.09

Operation

5602

5602

443

447

0.19

0.67

0.08

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Fischer Tropsch)

Feedstock

358

23

28

45

0.03

0.14

0.00

0.07

Fuel

3684

87

136

146

0.04

0.32

0.08

0.11

Operation

5602

0

427

431

0.19

0.67

0.07

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Soy BD20)

Feedstock

546

273

−39

−17

0.04

0.30

0.02

0.16

Fuel

12057

17

16

7

0.35

−0.04

0.00

−0.07

Operation

5602

4544

440

444

0.19

0.67

0.08

0.04

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CNG

Feedstock

557

31

39

82

0.04

0.21

0.00

0.09

Fuel

530

25

44

46

0.00

0.07

0.02

0.15

Operation

7177

0

426

436

0.21

0.52

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Dry Corn)

Feedstock

1051

292

−288

−222

0.08

0.53

0.03

0.24

Fuel

8022

440

92

105

0.33

0.64

0.06

0.24

Operation

6818

1804

514

518

0.30

0.52

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Wet Corn)

Feedstock

1148

636

−271

−184

−0.18

0.74

0.04

0.38

Fuel

8162

256

282

298

0.32

0.53

0.15

0.51

Operation

6818

1804

514

518

0.30

0.52

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Herbaceous)

Feedstock

728

276

−360

−302

0.07

0.37

0.02

0.07

Fuel

5903

228

4

19

0.24

0.57

0.04

−0.03

Operation

6818

1804

514

518

0.30

0.52

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

Btu/VMT

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

520

293

−337

−333

0.04

0.31

0.02

0.14

Fuel

5376

228

4

18

0.24

0.55

0.03

−0.03

Operation

6818

1804

514

518

0.30

0.52

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Dry Corn)

Feedstock

367

101

1

21

0.03

0.22

0.01

0.08

Fuel

1716

550

84

88

0.17

0.20

0.02

0.13

Operation

6818

6378

523

527

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Wet Corn)

Feedstock

375

131

3

25

0.01

0.24

0.01

0.09

Fuel

1728

534

101

105

0.17

0.19

0.03

0.16

Operation

6818

6378

523

527

0.32

0.52

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

339

100

−5

14

0.03

0.20

0.01

0.07

Fuel

1530

531

77

80

0.16

0.20

0.02

0.11

Operation

6818

6378

523

527

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Corn Stover)

Feedstock

320

101

−3

12

0.03

0.20

0.01

0.07

Fuel

1484

531

77

80

0.16

0.19

0.02

0.11

Operation

6818

6378

523

527

0.32

0.52

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Electric

Feedstock

203

72

16

32

0.04

0.11

0.16

0.05

Fuel

3494

103

485

487

0.01

0.68

0.02

1.68

Operation

2273

108

0

0

0.00

0.00

0.01

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

230

13

16

34

0.02

0.09

0.00

0.04

Fuel

1967

37

310

320

0.02

0.18

0.06

0.21

Operation

2964

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Grid-Independent SI HEV

Feedstock

203

56

15

25

0.02

0.13

0.00

0.05

Fuel

870

386

59

62

0.11

0.12

0.02

0.09

Operation

4607

4540

354

358

0.22

0.44

0.02

0.01

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Grid-Dependent SI HEV

Feedstock

203

61

15

27

0.02

0.12

0.06

0.05

Fuel

1736

293

199

202

0.08

0.31

0.02

0.61

Operation

3836

3077

237

240

0.15

0.29

0.02

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-5 GREET Energy and Emission Factors for Light-Duty Trucks 2 in 2005

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

324

89

8

25

0.03

0.20

0.01

0.07

Fuel

1730

637

100

107

0.18

0.24

0.03

0.16

Operation

7329

7021

562

567

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SI Autos (Tar Sands)

Feedstock

1189

86

70

89

0.03

0.20

0.01

0.08

Fuel

1805

637

101

108

0.18

0.24

0.03

0.16

Operation

7329

7021

562

567

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Conventional Oil)

Feedstock

328

90

24

41

0.03

0.20

0.01

0.07

Fuel

1403

623

95

99

0.18

0.20

0.03

0.14

Operation

7433

7326

571

576

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Tar Sands)

Feedstock

1206

88

87

106

0.03

0.20

0.01

0.08

Fuel

1476

623

95

100

0.18

0.20

0.03

0.15

Operation

7433

7326

571

576

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Conventional Oil)

Feedstock

324

89

8

25

0.03

0.20

0.01

0.07

Fuel

1730

637

100

107

0.18

0.24

0.03

0.16

Operation

7329

7021

562

567

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Tar Sands)

Feedstock

1189

86

70

89

0.03

0.20

0.01

0.08

Fuel

1805

637

101

108

0.18

0.24

0.03

0.16

Operation

7329

7021

562

567

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

269

74

26

40

0.02

0.17

0.01

0.06

Fuel

854

430

64

66

0.03

0.13

0.02

0.10

Operation

6108

6108

483

487

0.30

1.03

0.08

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Fischer Tropsch)

Feedstock

391

26

30

49

0.03

0.15

0.00

0.07

Fuel

4016

95

148

159

0.05

0.35

0.09

0.13

Operation

6108

0

466

470

0.30

1.03

0.07

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Soy BD20)

Feedstock

595

297

−42

−18

0.04

0.32

0.02

0.18

Fuel

13146

19

17

7

0.38

−0.05

0.00

−0.08

Operation

6108

4955

480

483

0.30

1.03

0.08

0.05

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

NG

Feedstock

607

34

43

90

0.05

0.23

0.00

0.10

Fuel

578

27

48

50

0.00

0.08

0.02

0.17

Operation

7825

0

463

480

0.54

1.03

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Dry Corn)

Feedstock

1146

319

−314

−242

0.09

0.58

0.03

0.26

Fuel

8747

480

101

114

0.36

0.69

0.07

0.26

Operation

7433

1967

561

565

0.78

1.03

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Wet Corn)

Feedstock

1252

693

−295

−200

−0.19

0.81

0.04

0.41

Fuel

8899

279

308

324

0.35

0.58

0.16

0.55

Operation

7433

1967

561

565

0.78

1.03

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Herbaceous)

Feedstock

794

301

−392

−330

0.08

0.40

0.02

0.08

Fuel

6436

249

5

21

0.26

0.63

0.04

−0.03

Operation

7433

1967

561

565

0.78

1.03

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

567

320

−367

−364

0.05

0.33

0.02

0.15

Fuel

5861

249

5

20

0.26

0.60

0.04

−0.03

Operation

7433

1967

561

565

0.78

1.03

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Dry Corn)

Feedstock

400

110

1

23

0.03

0.24

0.01

0.09

Fuel

1871

599

92

96

0.19

0.22

0.03

0.15

Operation

7433

6954

570

575

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Wet Corn)

Feedstock

409

143

3

27

0.01

0.26

0.01

0.10

Fuel

1884

582

110

114

0.19

0.21

0.04

0.17

Operation

7433

6954

570

575

0.82

1.03

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

369

109

−5

16

0.03

0.22

0.01

0.07

Fuel

1668

579

83

88

0.18

0.21

0.02

0.12

Operation

7433

6954

570

575

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Corn Stover)

Feedstock

349

110

−3

13

0.03

0.22

0.01

0.08

Fuel

1618

579

83

87

0.18

0.21

0.02

0.12

Operation

7433

6954

570

575

0.82

1.03

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Electric

Feedstock

221

78

17

35

0.04

0.12

0.18

0.06

Fuel

3810

112

529

531

0.01

0.74

0.02

1.83

Operation

2478

117

0

0

0.00

0.00

0.01

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

269

15

19

40

0.02

0.10

0.00

0.04

Fuel

2305

43

364

375

0.02

0.21

0.07

0.24

Operation

3474

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Grid-Independent SI HEV

Feedstock

234

64

17

29

0.02

0.15

0.01

0.05

Fuel

1002

445

68

71

0.13

0.14

0.02

0.10

Operation

5310

5233

408

412

0.75

0.80

0.02

0.01

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Grid-Dependent SI HEV

Feedstock

230

69

17

31

0.03

0.14

0.06

0.05

Fuel

1929

335

220

223

0.09

0.34

0.02

0.67

Operation

4375

3545

273

276

0.50

0.54

0.02

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-6 GREET Energy and Emission Factors for Light-Duty Autos in 2020

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

314

57

13

25

0.02

0.11

0.00

0.04

Fuel

1125

410

64

69

0.12

0.11

0.01

0.06

Operation

4753

4553

365

369

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SI Autos (Tar Sands)

Feedstock

913

55

60

73

0.02

0.12

0.01

0.04

Fuel

1177

410

65

70

0.12

0.11

0.01

0.06

Operation

4753

4553

365

369

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CG SI Autos (Conventional Oil)

Feedstock

314

57

13

25

0.02

0.11

0.00

0.04

Fuel

1125

410

64

69

0.12

0.11

0.01

0.06

Operation

4753

4553

365

369

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CG SI Autos (Tar Sands)

Feedstock

913

55

60

73

0.02

0.12

0.01

0.04

Fuel

1177

410

65

70

0.12

0.11

0.01

0.06

Operation

4753

4553

365

369

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SIDI Autos (Conventional Oil)

Feedstock

273

50

12

21

0.01

0.09

0.00

0.03

Fuel

979

357

56

60

0.10

0.10

0.01

0.06

Operation

4133

3959

317

321

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

RFG SIDI Autos (Tar Sands)

Feedstock

794

48

52

63

0.02

0.10

0.01

0.03

Fuel

1023

357

57

60

0.10

0.10

0.01

0.06

Operation

4133

3959

317

321

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

262

48

24

33

0.01

0.09

0.00

0.03

Fuel

560

279

42

43

0.02

0.06

0.01

0.04

Operation

3961

3961

313

317

0.06

0.08

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Diesel (Fischer-Tropsch)

Feedstock

254

17

20

32

0.02

0.07

0.00

0.04

Fuel

2345

61

85

91

0.03

0.19

0.05

0.08

Operation

3961

0

302

306

0.06

0.08

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Diesel (Soy BD20)

Feedstock

454

189

−22

−6

0.02

0.14

0.01

0.09

Fuel

8561

66

18

11

0.23

−0.05

0.00

−0.07

Operation

3961

3218

314

318

0.06

0.08

0.02

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

CNG

Feedstock

352

19

25

52

0.03

0.09

0.00

0.05

Fuel

332

14

27

29

0.00

0.03

0.01

0.05

Operation

4527

0

269

275

0.12

0.07

0.01

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Dry Corn)

Feedstock

730

208

−204

−163

0.04

0.22

0.01

0.11

Fuel

5621

265

61

70

0.22

0.35

0.03

0.09

Operation

4753

1245

358

362

0.14

0.07

0.01

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Wet Corn)

Feedstock

737

399

−198

−146

−0.12

0.34

0.02

0.19

Fuel

5770

182

200

211

0.22

0.25

0.09

0.13

Operation

4753

1245

358

362

0.14

0.07

0.01

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E85 (Herbaceous)

Feedstock

477

169

−252

−217

0.04

0.16

0.01

0.03

Fuel

3122

163

5

15

0.17

0.35

0.02

0.00

Operation

4753

1245

358

362

0.14

0.07

0.01

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

342

170

−239

−237

0.02

0.11

0.01

0.06

Fuel

2805

163

5

14

0.17

0.34

0.02

0.00

Operation

4753

1245

358

362

0.14

0.07

0.01

0.00

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Dry Corn)

Feedstock

350

70

8

22

0.02

0.12

0.01

0.04

Fuel

1200

379

58

61

0.12

0.11

0.01

0.06

Operation

4753

4446

365

368

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Wet Corn)

Feedstock

351

87

9

24

0.00

0.13

0.01

0.05

Fuel

1212

372

70

73

0.12

0.10

0.02

0.06

Operation

4753

4446

365

368

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

328

67

4

17

0.02

0.11

0.00

0.04

Fuel

981

370

53

56

0.11

0.11

0.01

0.05

Operation

4753

4446

365

368

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Corn Stover)

Feedstock

317

67

5

16

0.02

0.11

0.00

0.04

Fuel

953

370

53

56

0.11

0.10

0.01

0.05

Operation

4753

4446

365

368

0.15

0.07

0.01

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

Electric

Feedstock

126

41

9

20

0.02

0.04

0.09

0.03

Fuel

2061

53

283

285

0.00

0.23

0.01

0.53

Operation

1358

58

0

0

0.00

0.00

0.01

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

153

8

11

23

0.01

0.04

0.00

0.02

Fuel

1233

21

201

207

0.01

0.08

0.04

0.08

Operation

1964

0

0

0

0.00

0.00

0.01

0.00

Vehicle

792

160

62

65

0.21

0.09

0.04

0.29

Hydrogen (Liquid)

Feedstock

153

8

11

23

0.01

0.04

0.00

0.02

Fuel

3122

101

355

367

0.03

0.23

0.09

0.37

Operation

1964

0

0

0

0.00

0.00

0.01

0.00

Vehicle

792

160

62

65

0.21

0.09

0.04

0.29

Grid-Independent SI HEV

Feedstock

207

38

9

16

0.01

0.07

0.00

0.02

Fuel

740

270

42

45

0.08

0.07

0.01

0.04

Operation

3127

2996

240

244

0.11

0.06

0.01

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Grid-Dependent SI HEV

Feedstock

187

41

10

18

0.02

0.06

0.04

0.03

Fuel

1289

201

137

140

0.05

0.14

0.01

0.23

Operation

2618

2029

161

163

0.07

0.04

0.01

0.00

Vehicle

645

122

50

52

0.21

0.08

0.03

0.23

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-7 GREET Energy and Emission Factors for Light-Duty Trucks 1 in 2020

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

373

68

16

29

0.02

0.13

0.01

0.04

Fuel

1338

488

76

82

0.14

0.13

0.02

0.08

Operation

5652

5414

434

438

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SI Autos (Tar Sands)

Feedstock

1086

66

71

87

0.02

0.14

0.01

0.04

Fuel

1399

488

77

83

0.14

0.13

0.02

0.08

Operation

5652

5414

434

438

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Conventional Oil)

Feedstock

373

68

16

29

0.02

0.13

0.01

0.04

Fuel

1338

488

76

82

0.14

0.13

0.02

0.08

Operation

5652

5414

434

438

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Tar Sands)

Feedstock

1086

66

71

87

0.02

0.14

0.01

0.04

Fuel

1399

488

77

83

0.14

0.13

0.02

0.08

Operation

5652

5414

434

438

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Conventional Oil)

Feedstock

325

59

14

26

0.02

0.11

0.00

0.04

Fuel

1164

424

66

71

0.12

0.12

0.02

0.07

Operation

4915

4708

377

381

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Tar Sands)

Feedstock

944

57

62

75

0.02

0.12

0.01

0.04

Fuel

1217

424

67

72

0.12

0.12

0.02

0.07

Operation

4915

4708

377

381

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

311

57

28

39

0.02

0.10

0.00

0.04

Fuel

666

331

50

51

0.02

0.07

0.01

0.05

Operation

4710

4710

372

376

0.06

0.12

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Fischer-Tropsch)

Feedstock

302

20

23

38

0.03

0.08

0.00

0.05

Fuel

2789

72

101

109

0.03

0.23

0.06

0.09

Operation

4710

0

359

363

0.06

0.12

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Soy BD20)

Feedstock

540

224

–26

–7

0.02

0.16

0.01

0.11

Fuel

10179

78

21

13

0.28

–0.06

0.00

–0.09

Operation

4710

3827

373

377

0.06

0.12

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CNG

Feedstock

418

23

30

62

0.03

0.11

0.00

0.06

Fuel

395

17

33

34

0.00

0.03

0.01

0.06

Operation

5383

0

319

326

0.15

0.10

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Dry Corn)

Feedstock

868

247

–243

–193

0.05

0.27

0.01

0.13

Fuel

6683

316

72

83

0.26

0.41

0.04

0.11

Operation

5652

1480

426

430

0.17

0.10

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Wet Corn)

Feedstock

876

475

–236

–174

–0.14

0.40

0.02

0.22

Fuel

6861

217

237

251

0.26

0.30

0.10

0.16

Operation

5652

1480

426

430

0.17

0.10

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Herbaceous)

Feedstock

567

201

–300

–258

0.05

0.19

0.01

0.03

Fuel

3712

194

6

17

0.20

0.42

0.03

0.00

Operation

5652

1480

426

430

0.17

0.10

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

407

202

−284

−281

0.02

0.13

0.01

0.08

Fuel

3336

194

6

17

0.20

0.40

0.03

0.00

Operation

5652

1480

426

430

0.17

0.10

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Dry Corn)

Feedstock

417

84

10

26

0.02

0.14

0.01

0.05

Fuel

1426

451

69

72

0.14

0.13

0.02

0.07

Operation

5652

5287

434

437

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Wet Corn)

Feedstock

417

104

10

28

0.01

0.15

0.01

0.06

Fuel

1442

442

84

87

0.14

0.12

0.02

0.07

Operation

5652

5287

434

437

0.18

0.10

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

390

80

5

21

0.02

0.13

0.01

0.04

Fuel

1166

440

64

66

0.14

0.13

0.02

0.06

Operation

5652

5287

434

437

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Corn Stover)

Feedstock

376

80

6

19

0.02

0.13

0.01

0.05

Fuel

1134

440

64

66

0.14

0.12

0.02

0.06

Operation

5652

5287

434

437

0.18

0.10

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Electric

Feedstock

150

48

11

23

0.03

0.05

0.10

0.03

Fuel

2450

62

337

339

0.01

0.28

0.01

0.63

Operation

1615

69

0

0

0.00

0.00

0.01

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

181

10

13

27

0.01

0.05

0.00

0.03

Fuel

1466

26

238

246

0.01

0.10

0.04

0.09

Operation

2335

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Hydrogen (Liquid)

Feedstock

182

10

13

27

0.01

0.05

0.00

0.03

Fuel

3712

121

422

437

0.03

0.27

0.10

0.44

Operation

2335

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Grid-Independent SI HEV

Feedstock

246

45

10

19

0.01

0.08

0.00

0.03

Fuel

880

321

50

54

0.09

0.09

0.01

0.05

Operation

3718

3562

285

289

0.13

0.08

0.02

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Grid-Dependent SIHEV

Feedstock

222

49

11

22

0.02

0.07

0.04

0.03

Fuel

1533

239

163

166

0.06

0.17

0.01

0.28

Operation

3113

2413

191

194

0.09

0.06

0.01

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-8 GREET Energy and Emission Factors for Light-Duty Trucks 2 in 2020

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

RFG SI Autos (Conventional Oil)

Feedstock

436

80

19

34

0.02

0.15

0.01

0.05

Fuel

1564

570

89

96

0.16

0.16

0.02

0.09

Operation

6605

6327

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SI Autos (Tar Sands)

Feedstock

1269

77

83

101

0.03

0.16

0.01

0.05

Fuel

1635

570

90

97

0.16

0.16

0.02

0.09

Operation

6605

6327

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Conventional Oil)

Feedstock

436

80

19

34

0.02

0.15

0.01

0.05

Fuel

1564

570

89

96

0.16

0.16

0.02

0.09

Operation

6605

6327

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CG SI Autos (Tar Sands)

Feedstock

1269

77

83

101

0.03

0.16

0.01

0.05

Fuel

1635

570

90

97

0.16

0.16

0.02

0.09

Operation

6605

6327

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Conventional Oil)

Feedstock

379

69

16

30

0.02

0.13

0.01

0.04

Fuel

1360

496

78

83

0.14

0.14

0.02

0.08

Operation

5743

5502

441

445

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

RFG SIDI Autos (Tar Sands)

Feedstock

1103

67

72

88

0.03

0.14

0.01

0.04

Fuel

1422

496

79

84

0.14

0.14

0.02

0.08

Operation

5743

5502

441

445

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Diesel (Low Sulfur)

Feedstock

363

66

33

46

0.02

0.12

0.01

0.04

Fuel

778

387

58

60

0.02

0.09

0.01

0.06

Operation

5504

5504

435

439

0.07

0.17

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Fischer-Tropsch)

Feedstock

353

23

27

44

0.03

0.09

0.00

0.06

Fuel

3259

84

118

127

0.04

0.27

0.08

0.11

Operation

5504

0

420

424

0.07

0.17

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Diesel (Soy BD20)

Feedstock

631

262

−30

−8

0.03

0.19

0.01

0.13

Fuel

11895

92

25

16

0.32

−0.07

0.00

−0.10

Operation

5504

4472

436

440

0.07

0.17

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

CNG

Feedstock

489

27

35

72

0.04

0.13

0.00

0.07

Fuel

461

20

38

40

0.00

0.04

0.01

0.07

Operation

6290

0

373

381

0.18

0.14

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Dry Corn)

Feedstock

1014

288

−284

−226

0.06

0.31

0.01

0.15

Fuel

7810

369

85

97

0.31

0.48

0.05

0.13

Operation

6605

1730

498

502

0.20

0.14

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Wet Corn)

Feedstock

1024

555

−275

−203

−0.17

0.47

0.02

0.26

Fuel

8018

253

278

293

0.31

0.35

0.12

0.18

Operation

6605

1730

498

502

0.20

0.14

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E85 (Herbaceous)

Feedstock

663

234

−351

−302

0.05

0.22

0.01

0.04

Fuel

4337

227

7

20

0.23

0.49

0.03

0.00

Operation

6605

1730

498

502

0.20

0.14

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

 

 

Total Energy

Petroleum

CO2

CO2e

VOC

NOx

PM2.5

SOx

BTU/VMT

BTU/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

E85 (Corn Stover)

Feedstock

475

236

−332

−329

0.03

0.15

0.01

0.09

Fuel

3898

227

7

20

0.23

0.47

0.03

0.00

Operation

6605

1730

498

502

0.20

0.14

0.02

0.00

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Dry Corn)

Feedstock

487

98

11

31

0.03

0.16

0.01

0.06

Fuel

1667

527

81

84

0.17

0.15

0.02

0.08

Operation

6605

6178

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Wet Corn)

Feedstock

488

121

12

33

0.01

0.17

0.01

0.07

Fuel

1685

517

98

101

0.17

0.14

0.03

0.08

Operation

6605

6178

507

511

0.22

0.14

0.02

0.01

Vehicle

633

126

47

50

0.21

0.08

0.03

0.14

E10 (Herbaceous)

Feedstock

456

93

6

24

0.03

0.15

0.01

0.05

Fuel

1363

514

74

78

0.16

0.15

0.02

0.07

Operation

6605

6178

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

E10 (Corn Stover)

Feedstock

440

93

7

22

0.02

0.15

0.01

0.05

Fuel

1325

514

74

78

0.16

0.15

0.02

0.07

Operation

6605

6178

507

511

0.22

0.14

0.02

0.01

Vehicle

730

140

54

57

0.31

0.08

0.04

0.15

Electric

Feedstock

176

56

13

27

0.03

0.06

0.12

0.04

Fuel

2863

73

394

396

0.01

0.32

0.01

0.74

Operation

1887

80

0

0

0.00

0.00

0.01

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

Hydrogen (Gaseous)

Feedstock

232

13

16

34

0.02

0.06

0.00

0.03

Fuel

1875

33

305

314

0.02

0.13

0.05

0.12

Operation

2989

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Hydrogen (Liquid)

Feedstock

233

13

16

34

0.02

0.06

0.00

0.03

Fuel

4750

154

540

559

0.04

0.35

0.13

0.56

Operation

2989

0

0

0

0.00

0.00

0.01

0.00

Vehicle

1030

203

80

84

0.31

0.12

0.05

0.37

Grid-Independent SI HEV

Feedstock

305

56

13

24

0.02

0.10

0.00

0.04

Fuel

1094

399

62

67

0.11

0.11

0.01

0.06

Operation

4619

4424

354

358

0.20

0.11

0.02

0.01

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Grid-Dependent SIHEV

Feedstock

272

59

14

27

0.02

0.09

0.05

0.04

Fuel

1835

295

193

197

0.08

0.20

0.01

0.32

Operation

3821

2995

238

240

0.13

0.07

0.02

0.00

Vehicle

840

146

65

68

0.31

0.10

0.04

0.30

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Mobile6.2 Heavy-Duty Truck Energy and Emissions Factors

The operational factors for heavy-duty vehicles were determined with Mobile6.2 and are shown in Table D-9 and Table D-10. Default Mobile6.2 values were used for these vehicles.

GREET and Mobile6.2 Comparison

The GREET vehicle operation factors can be compared against Mobile6.2’s to evaluate the accuracy of particular vehicles. GREET assumes default emission factors for conventional gasoline and diesel vehicles and the operating conditions of the vehicles is not transparent. Mobile6.2 is designed to model emissions from conventional fuel vehicles and low level ethanol blends and provides the ability to adjust many vehicle operation and fuel characteristics in determining emission factors. Table D-11 and Table D-12 compare the GREET default conventional gasoline and diesel vehicle emissions against Mobile6.2. The lack of transparency in the vehicle and operating characteristics used to generate GREET factors results in some difficulty in verification using Mobile6.2. In 2005, GREET assumes low-sulfur concentrations of 26 ppm in gasoline and 200 ppm in conven-

TABLE D-9 Mobile6.2 Energy and Emission Factors for Heavy-Duty Vehicles in 2005

 

Total Energy

CO2

VOC

NOx

PM2.5

SOx

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

HDGV2A

12500

888

1.79

4.13

0.07

0.05

HDGV2B

12500

888

1.79

4.13

0.07

0.05

HDGV3

13587

963

2.47

4.71

0.08

0.06

HDGV4

14205

1005

5.30

5.90

0.07

0.06

HDGV5

15823

1124

3.10

5.40

0.06

0.06

HDGV6

15823

1119

2.91

5.30

0.07

0.07

HDGV7

17123

1217

3.43

6.09

0.07

0.07

HDGV8A

18382

1296

4.05

6.79

0.00

0.00

HDDV2A

10195

795

0.23

3.99

0.12

0.01

HDDV2B

10195

795

0.23

3.99

0.12

0.01

HDDV3

11250

879

0.25

4.44

0.13

0.01

HDDV4

12921

1004

0.31

5.41

0.11

0.01

HDDV5

13316

1036

0.32

5.68

0.25

0.01

HDDV6

15000

1176

0.47

7.99

0.26

0.01

HDDV7

17400

1354

0.58

9.94

0.33

0.01

HDDV8A

20077

1561

0.56

12.89

0.36

0.02

HDDV8B

21048

1647

0.66

15.10

0.36

0.02

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-10 Mobile6.2 Energy and Emission Factors for Heavy-Duty Vehicles in 2030

 

Total Energy

CO2

VOC

NOx

PM2.5

SOx

Btu/VMT

g/VMT

g/VMT

g/VMT

g/VMT

g/VMT

HDGV2A

12376

876

0.35

0.18

0.02

0.02

HDGV2B

12376

876

0.35

0.18

0.02

0.02

HDGV3

13298

945

0.76

0.23

0.02

0.02

HDGV4

13298

949

0.82

0.21

0.02

0.02

HDGV5

15625

1107

0.91

0.24

0.02

0.02

HDGV6

15432

1090

0.90

0.24

0.02

0.02

HDGV7

16779

1191

0.95

0.27

0.03

0.02

HDGV8A

17606

1255

1.00

0.28

0.00

0.00

HDDV2A

10038

785

0.10

0.25

0.01

0.01

HDDV2B

10038

785

0.10

0.25

0.01

0.01

HDDV3

11154

873

0.12

0.26

0.02

0.01

HDDV4

12794

998

0.14

0.41

0.02

0.01

HDDV5

13182

1030

0.15

0.44

0.02

0.01

HDDV6

15000

1169

0.19

0.47

0.02

0.01

HDDV7

17400

1352

0.23

0.58

0.03

0.01

HDDV8A

19773

1544

0.26

0.64

0.03

0.02

HDDV8B

20714

1616

0.29

0.75

0.03

0.02

TABLE D-11 Comparison of Emission Factors (g/VMT) for a Light-Duty Gasoline Automobile in 2005

 

VOC Exhaust

VOC Evap

NOx

PM2.5 Exhaust

PM2.5 TBW

SOx

GREET

0.15

0.07

0.3

0.008

0.007

0.01

Mobile6.2

0.27

0.87

0.8

0.005

0.007

0.02

TABLE D-12 Comparison of Emission Factors (g/VMT) for a Light-Duty Diesel Automobile in 2005

 

VOC Exhaust

NOx

PM2.5 Exhaust

PM2.5 TBW

GREET

0.09

0.3

0.07

0.007

Mobile6.2

0.33

1.3

0.15

0.007

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

tional diesel. GREET further specifies sulfur contents for low-sulfur diesel. Outside of fuel sulfur levels, vehicle emission factors are fixed based on inputs and assumptions from 1990 through 2020.

The differences between GREET and Mobile6.2 emission factors are most likely due to the variations in vehicle operation and fuel input parameters. These differences could be from cold start and warm running, fuel vapor pressure, summer or winter fuel mix, and vehicle model assumptions. While the Mobile6.2 factors tend to be larger than the GREET factors. The GREET factors are assumed to be reasonable, given the uncertainty in vehicle and fuel parameters and that they are within the bounds of Mobile6.2 estimates for the year.

EPA Mobile6 Ammonia Emissions Factors

Ammonia emissions, which ultimately contribute to particulate formation, are evaluated by APEEP but not included in the default transportation damage assessment. GREET does not evaluate ammonia emissions but Mobile6.2 does for a subset of vehicle and fuel combinations included in GREET. Table D-13 summarizes the Mobile6.2 ammonia emission factors for 2005 and 2030.

For light-duty gasoline vehicles, the ammonia factors are about 0.1 g/VMT; for light-duty diesel vehicles, they range from 0.01 to 0.03 g/VMT for both years. The heavy-duty gasoline and diesel vehicle factors are 0.05 and 0.03 g/VMT.

Applying GREET Feedstock and Fuel Production Factors to Heavy-Duty Vehicles

Feedstock and fuel production factors from GREET are used to supplement the Mobile6.2 heavy-duty-vehicle operational emissions. Because Mobile6.2 evaluates only the operational phase of heavy-duty vehicles, there is a need to supplement this component with feedstock and fuel production requirements so that results are commensurate with light-duty vehicles evaluated in GREET. To do this, the GREET feedstock and fuel production factors from reformulated gasoline and low-sulfur diesel light-duty vehicles are used. Using the energy content of gasoline or diesel consumed during vehicle operation, the corresponding GREET feedstock and fuel production factors are prorated and assessed to the heavy-duty vehicles. This procedure is done across all of the energy and emissions factors for each of the heavy-duty vehicles assessed with Mobile6.2.

Heavy-duty vehicle-manufacturing factors are not included in the assessment. Unlike feedstock and fuel production processes that are specific to a fuel (which is the same for both light- and heavy-duty vehicles), vehicle-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

TABLE D-13 Mobile6.2 Ammonia Emissions (g/VMT)

 

2005

2030

HDGV2B

0.045

0.045

HDGV3

0.045

0.045

HDGV4

0.045

0.045

HDGV5

0.045

0.045

HDGV6

0.045

0.045

HDGV7

0.045

0.045

HDDV2B

0.027

0.027

HDDV3

0.027

0.027

HDDV4

0.027

0.027

HDDV5

0.027

0.027

HDDV6

0.027

0.027

HDDV7

0.027

0.027

HDDV8A

0.027

0.027

HDDV8B

0.027

0.027

LDGV

0.100

0.102

LDGT1

0.100

0.102

LDGT2

0.097

0.102

LDGT3

0.097

0.102

LDDV

0.007

0.007

LDDT

0.027

0.027

LDDT12

0.007

0.007

manufacturing processes are unique. There is no known information that estimates the energy requirements and resulting emissions of manufacturing heavy-duty gasoline and diesel fuels of different classes. As a result, this component was excluded from the assessment.

COUNTY-LEVEL DAMAGE CALCULATIONS

The vehicle feedstock, fuel, operation, and manufacturing per VMT emission factors are used in conjunction with APEEP county unit-damage factors to determine county resolution total damages. For each of the lifecycle components, particular assumptions were made in performing the calculations. APEEP has county-level pollutant-unit damages for all states except Alaska and Hawaii. For every county, APEEP reports ground levels and various heights of emission-unit damages (dollar per metric tonne emitted) for VOCs, NOx, PM2.5, SO2, and NH3 (ammonia).

Feedstock Production Damages

The location of feedstock production and associated emissions is not clear for the various fuel energy inputs. From crude oil to corn to coal, the

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

identification of feedstock production locations is not transparent. Feedstock can be produced internationally (for example, conventional crude oil from overseas or tar sands crude oil from Canada) or domestically (for example, coal or corn), and transport of raw energy inputs can occur along the fuel production pathway. The difficulty of estimating feedstock production and transport locations resulted in the assignment of these emissions to the county where travel occurs. The feedstock emissions are assessed the lowest level above ground-level height in APEEP.

Fuel Production Damages

Fuel production damages are assessed to particular geographic regions based on petroleum refinery and ethanol plant locations. PADD (Petroleum Administration for Defense Districts) regions are used to identify five geographic areas of the United States for petroleum production and consumption statistics. The regions are East Coast, Midwest, Gulf Coast, Rocky Mountain, and West Coast and serve as a common resolution for petroleum data. The U.S. Energy Information Administration reports petroleum refinery locations and production capacity (EIA 2009b). Using these locations, associated counties could be determined for assessment of APEEP damage factors for conventional fueled vehicles. Without knowing which refinery produces the fuel for a VMT in another county, PADD resolution was used to assess fuel production unit damages. For each PADD, a weighted-average APEEP fuel factor (further referred to as APEEPFUEL) was determined from the percentage of PADD fuel production capacity for each refinery and the corresponding county. The result produced five APEEPFUEL pollutant damage factors, one for each PADD. The APEEPFUEL damage factors were assessed to each county in the United States based on its PADD location. The fuel production life-cycle emissions were used in conjunction with the APEEPFUEL factors to determine fuel production damages for each county given a specific vehicle’s per VMT emissions.

A PADD-based resolution approach was also used for ethanol fuel production. Using ethanol refinery locations (RFA 2009), APEEPFUEL factors were determined for ethanol production for each of the five PADD regions. Given the mix of ethanol in the fuel (10% or 85%), this fraction was multiplied by the APEEPFUEL ethanol factor and the remainder by the APEEP FUEL gasoline factor. For example, for an E10 vehicle operating in a county in PADD 1, 10% × APEEPFUEL,ETHANOL and 90% × APEEPFUEL,GASOLINE are added and assessed to that county. This mixed APEEPFUEL factor for each pollutant is then multiplied by the corresponding fuel production emissions for an E10 vehicle. Similar to feedstock production, the fuel production APEEP factors are based on the lowest level height above ground level.

For electric vehicles, power-plant emissions were assumed to occur ac-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

cording to petroleum PADD locations. Given the complexity of modeling electricity-generation emissions associated with specific driving locations, fuel production emissions were assigned to the petroleum production locations within relevant PADD regions.

Vehicle Operation Damages

Vehicle operation VMT are based on county populations, which are assumed to be a reasonable metric for disaggregation of total state VMT. Given the GREET and Mobile6.2 per VMT emissions factors, VMT estimates are needed for each U.S. county to determine total emissions in that county. State-level VMT is available but not any higher resolution (FDA 2008). Using U.S. census population estimates, state-level VMT is disaggregated to each county by the fraction of population. These county VMT are then multiplied by the GREET and Mobile6.2 vehicle operational emission factors to determine total emissions for each county. The emissions of each pollutant are then joined with the APEEP ground-level-pollutant county factors to determine total damages.

Vehicle-Manufacturing Damages

PADD regions are used to aggregate vehicle-manufacturing APEEP costs, similar to fuel production. Census data were examined for information on vehicles, parts, and tire manufacturing facilities (including number of facilities, employee counts, and county). The census data details the location and employee count for over 8,000 facilities. For each county in the United States, the total number of employees from these industries was determined. A weighted-average vehicle-manufacturing APEEP factor (further referred to as APEEPMANUFACTURING) was determined for each PADD based on the percentage of employees and the APEEP factor foreach county in a PADD. Again, this process was done because of the lack of information that identifies whether a vehicle is driven in a particular county where it was manufactured. The PADD-based approach assumes that for a vehicle driven in a particular county, the manufacturing took place in that county’s PADD and the weighted-average APEEPMANUFACTURING factor is applied.

Total Life-Cycle Damages

Total damages are determined from feedstock production, fuel production, vehicle operation, and vehicle-manufacturing factors. This assessment was performed for each vehicle and fuel combination. Given a specific vehicle and fuel combination, the feedstock, fuel, operation, and manufacturing emission factors (in grams of VOC, NOX, PM2.5, and SO2 per VMT)

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

are multiplied by the APEEP county and pollutant factors (dollar damages per gram of pollutant, which may be weighted averages for the PADD region). Furthermore, the APEEP factors are reported in dollars of damage of emission for mortality, morbidity, and other damages (for example, agricultural or visibility impairment). For each vehicle and fuel combination, the life-cycle emission factors are joined with the APEEP pollutant damage factors for mortality, morbidity, and other to determine total damages for each county. The result is a mortality-morbidity-and-other dollar damages for each county and each vehicle type (light-duty autos, truck 1, and truck 2) in both 2005 and 2030.

Damages Related to Electric Vehicles and Grid-Dependent Hybrids

For the vehicle-manufacturing component and the fuel feedstock (for example, coal or natural gas) component of the life cycles of electric vehicles (EVs) and grid-dependent hybrid vehicles (GD-HVs), the GREET model’s estimates of emissions per VMT were paired with results from the APEEP model, a process that provided estimates of the physical health and other nonclimate-change-related effects and monetary damages per ton of emissions that form criteria air pollutants. However, the allocation of electric-utility-related damages to the vehicle operations and electricity production components of the life cycles were approximated by applying a GREET-generated kWh/VMT and applying that to the estimated average national damages per kWh from the electricity analysis presented in Chapter 2.

The committee used 1.59 cents/kWh for 2005 and 0.79 cents/kWh for 2030 for the damages due to producing (not consuming) electricity for both EVs and GD-HEVs. Those values were obtained by determining the aggregate marginal damages for coal-fired and natural gas plants based on their shares of net generation and the average marginal damages for each type of plant. For example, for 2005: [0.485 (coal share of net generation) × 3.2 cents/kWh] + [0.213 (natural gas share of net generation) × 0.16 cents/kWh] = 1.59 cents/kWh.

We estimated the fuel (electricity generation) component damages based on the damages associated with producing electricity at the rate of 0.52 kWh/VMT, and the fuel damages for 2005 were calculated as follows: 0.52 kWh/VMT × 1.59 cents/kWh = 0.83 cents/VMT. For 2030, the estimate for fuel damage is 0.31 cents/VMT. For the vehicle operation component, we estimated damage associated with a 10% loss of electricity over transmission and distribution lines (for example, 0.05 kWh/VMT for 2005) (DOE 2009).

A similar approach was used for estimating the electricity-related dam-

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×

ages for GD-HEVs. However, no more than 35% of energy supplied to GD-HEVs was estimated to come from the grid.

REFERENCES

Argonne National Laboratory. 2009. The Greenhouse Gases, Regulated Emissions, and Energy Use on Transportation (GREET) Model. U.S. Department of Energy, Argonne National Laboratory [online]. Available: http://www.transportation.anl.gov/modeling_simulation/GREET/ [accessed Oct. 12, 2009].

DOE (U.S. Department of Energy). 2009. Overview of the Electric Grid. Office of Electricity Delivery and Energy Reliability, U.S. Department of Energy [online]. Available: http://sites.energetics.com/gridworks/grid.html [accessed Sept. 4, 2009].

EIA (Energy Information Administration). 2006. Annual Energy Outlook 2007, With Projections to 2030. DOE/EIA-0383(2007). Energy Information Administration, Office of Integrated Analysis and Forecasting, U.S. Department of Energy, Washington, DC. February 2006 [online]. Available: http://tonto.eia.doe.gov/ftproot/forecasting/0383(2007).pdf [accessed Nov. 19, 2009].

EIA (Energy Information Administration). 2009a. Annual Energy Outlook 2009, With Projections to 2030. DOE/EIA-0383(2009). Energy Information Administration, Office of Integrated Analysis and Forecasting, U.S. Department of Energy, Washington, DC. March 2009 [online]. Available: http://www.eia.doe.gov/oiaf/aeo/pdf/0383(2009).pdf [accessed Apr. 22, 2009].

EIA (Energy Information Administration). 2009b. Ranking of U.S. Refineries. Energy Information Administration [online]. Available: http://www.eia.doe.gov/neic/rankings/refineries.htm [accessed Nov. 19, 2009].

EPA (U.S. Environmental Protection Agency). 2009. Mobile6 Vehicle Emission Modeling Software. U.S. Environmental Protection Agency [online]. Available: http://www.epa.gov/OMS/m6.htm [accessed Nov. 13, 2009].

FDA (Federal Highway Administration). 2008. Highway Statistics Series. Policy Information. U.S. Department of Transportation, Federal Highway Administration [online]. Available: http://www.fhwa.dot.gov/policy/ohpi/hss/index.cfm [accessed Nov. 13, 2009].

RFA (Renewable Fuel Association). 2009. Biorefinery Locations. Renewable Fuel Association, Washington, DC [online]. Available: http://www.ethanolrfa.org/industry/locations/ [accessed Nov. 13, 2009].

Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 432
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 433
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 434
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 435
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 436
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 437
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 438
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 439
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 440
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 441
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 442
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 443
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 444
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 445
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 446
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 447
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 448
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 449
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 450
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 451
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 452
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 453
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 454
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 455
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 456
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 457
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 458
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 459
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 460
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 461
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 462
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 463
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 464
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 465
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 466
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 467
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 468
Suggested Citation: "Appendix D: Description of GREET and Mobile6 Models and Their Applications." National Research Council. 2010. Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Washington, DC: The National Academies Press. doi: 10.17226/12794.
×
Page 469
Next: Appendix E: Supplemental Information on Land-Use Externalities from Biofuels: A Case Study of the Boone River Watershed »
Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use Get This Book
×
Buy Paperback | $47.00
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Despite the many benefits of energy, most of which are reflected in energy market prices, the production, distribution, and use of energy causes negative effects. Many of these negative effects are not reflected in energy market prices. When market failures like this occur, there may be a case for government interventions in the form of regulations, taxes, fees, tradable permits, or other instruments that will motivate recognition of these external or hidden costs.

The Hidden Costs of Energy defines and evaluates key external costs and benefits that are associated with the production, distribution, and use of energy, but are not reflected in market prices. The damage estimates presented are substantial and reflect damages from air pollution associated with electricity generation, motor vehicle transportation, and heat generation. The book also considers other effects not quantified in dollar amounts, such as damages from climate change, effects of some air pollutants such as mercury, and risks to national security.

While not a comprehensive guide to policy, this analysis indicates that major initiatives to further reduce other emissions, improve energy efficiency, or shift to a cleaner electricity generating mix could substantially reduce the damages of external effects. A first step in minimizing the adverse consequences of new energy technologies is to better understand these external effects and damages. The Hidden Costs of Energy will therefore be a vital informational tool for government policy makers, scientists, and economists in even the earliest stages of research and development on energy technologies.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Done