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Publication #FE796

Fuel Sources and Carbon Dioxide Emissions by Electric Power Plants in the United States1

Alan W. Hodges and Mohammad Rahmani2

Introduction

The issue of global warming has drawn more attention in recent years due to rising sea levels, glacier retreat, Arctic shrinking, and altered patterns of agriculture (National Geographic 2007). Human activities add to global warming through carbon dioxide released by using coal, petroleum, natural gas, and other sources to produce energy for human consumption (IPCC 2007). Global warming has become an issue of concern because of its negative effects on the environment, human health, and economic well-being of all the people of the world (U.S. EPA 2008). The Intergovernmental Panel on Climate Change (IPCC) has set the goal of reducing carbon dioxide to 350 ppm (parts per million) by 2025 (EEA 2008). Nations and the international community as a whole are trying to bring the rate of increase in emissions of greenhouse gases under control, or to mitigate the effects of such emissions through carbon capture and storage (sequestration) technologies. Renewable Portfolio Standard (RPS) and Renewable Fuel Standard (RFS) policies adopted by many states are efforts to mitigate carbon dioxide emissions (USDOE/EIA 2008). RPS requires electric power facilities to use a minimum percentage of their fuel from renewable sources, and RFS requires blending of renewable fuels (ethanol) with gasoline at specified minimum levels.

Carbon dioxide (CO2) accounted for nearly 85 percent of total greenhouse gas emissions in 2006, with the balance from methane (CH4), nitrogen oxides (NO2), and fluorocarbons (HFC, PFC, and SF6). Electric power generation contributed almost 41 percent of the CO2 emissions from fossil fuels in the United States and 34 percent of all greenhouse gas emissions, the largest share of all major sectors of the U.S. economy, as shown in Table 1 (U.S. EPA 2008). Most electric power plants utilize coal and natural gas as the principal fuels. However, some are beginning to use non-polluting energy sources (e.g., sun, wind, and hydropower) and biomass fuels (which have little or no net emissions over the life cycle of feedstock growth and bio-fuel use) to generate electricity.

This report summarizes trends in carbon dioxide emissions of electric power plants by type of fuel and by state in the United States during the 2003–2007 period.

Data

This analysis uses monthly data, summarized annually for 2003–2007, on fuel consumption and electricity generation by electric power plants and industrial heat and power systems in the United States. The data are collected and published by the U.S. Department of Energy, Energy Information Administration (USDOE/EIA). Carbon dioxide uncontrolled emission factors are used to estimate the annual volume of carbon dioxide emissions by type of fuel used for electricity generation. Emission factors are the amount of carbon dioxide emitted per unit energy generated (pounds per million Btu/MMBtu) for each fuel type, based on EIA and Environmental Protection Agency (U.S. EPA) estimates. The most recent emission factors available from the 2000–2007 U.S. EPA studies were used for this analysis. The emission factor for mixed biogenic and non-biogenic municipal solid waste was adjusted upward based on U.S. EPA estimates from a 1997 study which showed that municipal solid waste in the United States contained 15.9 percent plastics. Table 2 shows the carbon dioxide emission factors by fuel groups and specific energy sources. Of course, nuclear and most renewable energy sources do not have direct CO2 emissions. While biomass fuels do emit CO2 upon combustion, the carbon is reabsorbed by growing plants over the lifecycle of biofuel production. However, direct emissions from biomass combustion are included in this analysis.

Electricity Generation and Fuel Types

The total electricity generation by electric power plants in the United States, net of internal uses, was about 4.2 gigawatt-hours (GWh, billion watt-hours) in 2007, as shown in Table 3. Three major fuel groups were used by electric power plants to generate electricity: coal, at over 48 percent, or more than 2 billion watt-hours; natural gas and propane, at over 21 percent, or nearly 900 million watt-hours; and nuclear energy, at 19 percent, or more than 800 million watt-hours. Renewable sources of energy, such as solar, geothermal, water, and wind, generated a total of 291 million watt-hours, or 7 percent of total electricity, and biomass generated 64 million watt-hours, or 1.5 percent, to the net electricity generation in the United States in 2007 (Table 3).

Trends in electricity generation for each energy source during the 2003–2007 period are summarized in Table 3, and charted for major fuel groups in Figure 1. Total electricity generation increased by about 7 percent between 2003 and 2007. Generation from natural gas and propane showed a significant increase of more than 37 percent during this time. Generation from all non-biomass renewable energy sources, such as solar, water, wind, and geothermal, which result in no or minimal emissions of carbon dioxide, actually decreased during this period. However, use of solar energy to produce electricity increased by more than 13 percent during the 2003–2007 period. Wind is now the fastest growing source of electricity due to substantial investments, particularly in the Great Plains region of the United States, with generation increasing by almost threefold over the last five years. Major efforts to promote greater use of biomass fuels for electricity generation have resulted in this source increasing by over 7 percent. It should be noted that biomass is considered carbon neutral because the carbon released during combustion is recaptured through plant growth. Woody biomass captures carbon from the atmosphere, whereas fossil fuels transfer underground carbon to the atmosphere (Biomass Energy Resource Center 2008). Higher petroleum prices have negatively affected the use of this fuel for generating electricity, decreasing its share by 51 percent since 2003, and it now represents only a little more than 1 percent of all fuel types used for electricity in 2007.

Figure 1. 

Net electricity generation by U.S. power plants by major fuel groups, 2003–2007.


[Click thumbnail to enlarge.]

Carbon Dioxide Emissions and Fuel Types

The total carbon dioxide emissions by electric power plants in the United States exceeded 2.5 billion metric tons (2.756 Bn tons) in 2007 (Table 4). The largest fuel groups—coal, natural gas, and propane—dominated carbon dioxide emissions, over 94 percent of the total in 2007. Coal alone represented 78 percent of all CO2 emissions by electric power plants, or nearly 2 billion metric tons in 2007.

While total carbon dioxide emissions by power plants increased by 5 percent between 2003 and 2007, various fuel types showed different trends during this period. Bituminous coal, the highest contributor to power plant CO2 emissions in 2007 (38%), showed a slight decrease of 1.6 percent when compared to 2003, whereas sub-bituminous coal, the second largest contributor to CO2 emissions, registered an almost 9 percent increase between 2003 and 2007. Lignite coal, with only a 3.5 percent share of CO2 emissions in 2007, decreased its contribution towards CO2 emissions by more than 10 percent. At the same time, the share of emissions from coal-based synfuels increased by more than 26 percent. Natural gas showed an increase in CO2 emissions of more than 34 percent between 2003 and 2007. Biomass accounted for only 2.7 percent of CO2 emissions in 2007, but its share of carbon dioxide emissions decreased by 6 percent between 2003 and 2007. Figure 2 illustrates the trend during the 2003–2007 period in CO2 emissions for the major fuel groups.

Figure 2. 

CO2 emissions by U.S. power plants by major fuel groups, 2003–2007.


[Click thumbnail to enlarge.]

Emission Ratios

The emission ratio represents the amount of CO2 emitted per unit of electricity generated (metric tons CO2 per megawatt-hour). This relationship was used to compare CO2 emissions by electric power plants across the United States, irrespective of differences in area, population, and other characteristics. Emission ratios are shown in Table 5 by state for 2007 and 2003 and the percentage change during this period. Power plants in states with lower emission ratios used more environmentally friendly fuel sources than those with higher emission ratios. Vermont and Washington had the lowest emission ratios of 0.09 and 0.13, respectively, in 2007, and the highest decrease in emission ratios during the 2003–2007 period. Wyoming and North Dakota had the highest emission ratios of 0.99 and 1.02, respectively (Table 5).

Conclusions

Coal contributed over 78 percent of the total carbon dioxide emissions by electric power plants, but generated less than half (48.6%) of all the electricity generated by U.S. power plants in 2007. Natural gas showed significantly lower CO2 emissions for the electricity it generated (16% of CO2 emissions for 21.5% of the generated electricity). Biomass fuels produced only 0.5 percent of the electricity in 2007and caused 2.7 percent of the CO2 emissions. Non-biomass renewable fuel sources generated 7 percent of the electricity and produced less than 0.1 percent of carbon dioxide emissions. Nuclear energy generated a significant share of electricity (19.4%). However, the claim that nuclear energy does not cause any CO2 emissions has been challenged by the fact that extraction, production, and processing of fissile fuels (uranium, plutonium, and thorium) indirectly involve greenhouse gas emitting industries (Fritsche 1997). While the trend for electricity generation between 2003 and 2007 showed a 37 percent increase in natural gas usage, the use of non-polluting energy sources (e.g., sun, wind, and hydropower) registered a 1.1 percent decrease during the same time period. A 183 percent increase in wind energy usage during the 2003–2007 period is evidence of the potential for wind energy, although its share in electricity generation is still very small (0.8 percent).

A recent report by the International Energy Agency estimated that $45 trillion is needed to cut world carbon emissions in half by 2050 (Kanter 2008). Certainly, a major portion of this amount will be spent on low- or non-CO2 emitting sources of energy. The application of new technologies for using solar energy and an increased focus on wind energy for electricity generation show great promise in reducing CO2 emissions. States such as Nebraska, Nevada, New York, Oklahoma, Vermont, and Washington have reduced their emission ratios by over 10 percent since 2003 using energy sources with lower CO2 emissions.

To reduce greenhouse gas emissions, many states have adopted a Renewable Portfolio Standard policy requiring electric power facilities to reach a specified minimum percentage of their fuels from renewable resources by a certain date (USDOE/EIA 2007). Presently, 30 states (including the District of Columba) have adopted a mandatory Renewable Portfolio Standard (RPS), and four states have voluntary goals. The mandated goals for renewable resource use range from 4 percent in Massachusetts in 2009 to 25 percent in Illinois, Minnesota, and Oregon in 2025 (USDOE/EIA 2007). It is assumed that the use of renewable energy resources will reduce greenhouse gas emissions. Renewable Portfolio Standards may bring economic and health benefits such as job creation and cleaner air in addition to reducing greenhouse gas emissions (PEW Center 2008).

References

Bioenergy Resource Center. 2008. Biomass emissions: Air emissions from modern wood energy systems. Biomass Energy Resource Center, Montpelier, VT. http://www.biomasscenter.org/index.php/resources/fact-sheets/fse-biomass-emissions.html

EEA. 2008. Climate change targets: 350 ppm and the EU two-degree target. European Environment Agency, Copenhagen, Denmark (June 23). http://www.eea.europa.eu/highlights/climate-change-targets-350-ppm-and-the-eu-2-degree-target

Fritsche, Uwe R. 1997. Comparing greenhouse-gas emissions and abatement costs of nuclear and alternative energy options from a life-cycle perspective. Paper presented at the CNIC Conference on Nuclear Energy and Greenhouse-Gas Emissions, Tokyo, Japan (November).

Kanter, James. 2008. Nations urged to spend $45 trillion to battle carbon emission. International Herald Tribune, June 6. http://www.nytimes.com/2008/06/06/business/worldbusiness/06iht-energy.2.13521947.html

IPCC. 2007. Climate Change 2007. Synthesis Report to Intergovernmental Panel on Climate Change, Valencia, Spain (November). http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf

National Geographic. 2007. Effects of Global Warming. http://environment.nationalgeographic.com/environment/global-warming/gw-effects.html

PEW Center. 2008. Global Climate Change. Renewable Portfolio Standards (RPS). PEW Center, Arlington, VA (May). http://www.pewclimate.org/what_s_being_done/in_the_states/rps.cfm

U.S. DOE/EIA. 2008., EIA-906/920 Fuel Stock Data at Electric Power Generating Facilities, 2003-2007. U.S. Department of Energy, The Energy Information Administration, Washington, D.C. http://www.eia.doe.gov/cneaf/electricity/page/eia906_920.html

U.S. DOE/EIA. 2009. Carbon Dioxide Uncontrolled Emission Factor, Electric Power Annual with Data for 2007. U.S. Department of Energy, Energy Information Administration, Washington, D.C. (January). http://www.eia.doe.gov/cneaf/electricity/epa/epata3.html

U.S. DOE/EIA. 2007. States with Renewable Portfolio Standard. U.S. Department of Energy, Energy Information Administration, Washington, D.C. (June). http://eetd.lbl.gov/ea/EMP/reports/62569.pdf [May 7, 2012].

U.S. EPA. 2008. Climate Change, Basic Information. U.S. Environmental Protection Agency, Washington, D.C. (April 1). http://www.epa.gov/climatechange/basicinfo.html

U.S. EPA. 2007. Renewable Fuel Standard Implementation: Frequently Asked Consumer Questions. EPA420-F-07-062, U.S. Environmental ProtectionAgency, Washington, D.C. [25 March 2013].

U.S. EPA. 2008. U.S. Greenhouse Gas Inventory Reports–Trends in Greenhouse Gas Emissions. U.S. Environmental Protection Agency, Washington, D.C. (April 10). http://www.epa.gov/climatechange/emissions/usinventoryreport.html

Tables

Table 1. 

Greenhouse gas emissions by major sectors of the U.S. economy, 2006.

Sector

Emissions

Percent of Total

 

(Tg CO2 equivalent)

(%)

Electric Power

2,338

34

Transportation

1,970

28

Industry

1,372

20

Agriculture

534

8

Commercial

395

6

Residential

345

5

Total

6,952

100

Source: U.S. Environmental Protection Agency (2008).

Table 2. 

Carbon dioxide emission factors for electric power generation by fuel types in the United States.

Fuel Group

Energy Source

Pounds Per Million Btu

Biomass

Agriculture Crop Byproducts

195.0

 

Black Liquor

195.0

 

Landfill Gas

115.1

 

Municipal Solid Waste (mixed biogenic & non-biogenic)

179.6

 

Municipal Solid Waste (non-biogenic)

195.0

 

Other Biomass Gases

115.1

 

Other Biomass Liquid (ethanol, fish oil)

115.1

 

Other Biomass Solid (animal manure; waste)

195.0

 

Sludge Waste

199.5

 

Wood Waste Liquids (red liquor; sludge wood)

195.0

 

Wood Waste Solids (paper; pellets; railroad ties; utility poles)

195.0

Coal

Bituminous and Anthracite Coal

205.3

 

Lignite Coal

215.4

 

Coal-Based Synfuel (briquettes; pellets; extrusions)

205.3

 

Sub-Bituminous Coal

212.7

 

Waste / Other Coal

205.3

Natural Gas & Propane

Natural Gas

117.1

 

Propane

139.2

Nuclear

Nuclear (uranium; plutonium; thorium)

0.0

Petroleum

Distillate Fuel Oil (diesel and No. 1, 2 & 4 fuel oils)

161.4

 

Jet Fuel

156.3

 

Kerosene

159.5

 

Residual Fuel Oil (No. 5, 6 & Bunker C fuel oil)

173.9

 

Waste Oil (liquid butane; crude oil; liquid byproducts

210.0

Renewables (non-biomass)

Solar (photvoltaic; thermal)

0.0

 

Geothermal

16.6

 

Water (conventional; pumped storage)

0.0

 

Wind

0.0

Residual

Blast Furnace Gas

117.0

 

Municipal Solid Waste (non-biogenic)

91.9

 

Other Gas (butane; coal processes; coke-oven)

141.5

 

Other (batteries; chemicals; coke breeze; hydrogen)

0.0

 

Petroleum Coke

225.1

 

Purchased Steam

0.0

 

Tires

189.5

Source: Energy Information Administration, Carbon Dioxide Uncontrolled Emission Factors, Electric Power Annual Data for 2000–2007 (http://www.eia.doe.gov/cneaf/electricity/epa/epata3.html).

Table 3. 

Net electricity generation by energy source in the United States, 2003–2007.

Fuel Group and Energy Source

2003

2004

2005

2006

2007

Change 2003–07

Share 2007

 

(gigawatt–hours)

(%)

(%)

Coal

1,973,737

1,978,620

2,013,179

1,990,926

2,020,572

2.4

48.6

 

Bituminous and Anthracite Coal

1,063,588

1,022,139

1,042,601

1,039,727

1,040,008

–2.2

25.0

 

Lignite Coal

91,834

88,973

91,054

88,382

82,894

–9.7

2.0

 

Coal-Based Synfuel

55,508

71,339

70,241

57,287

73,135

31.8

1.8

 

Sub-Bituminous Coal

753,820

785,637

796,645

791,639

810,150

7.5

19.5

 

Waste / Other Coal

8,987

10,531

12,639

13,890

14,385

60.1

0.3

Natural Gas & Propane

649,924

708,875

757,989

813,061

893,244

37.4

21.5

 

Natural Gas

649,908

708,853

757,974

813,044

893,211

37.4

21.5

 

Propane

16

21

15

17

32

101.4

0.0

Nuclear (uranium; plutonium; thorium)

763,733

788,528

781,986

787,219

806,487

5.6

19.4

Renewable (non-biomass)

294,514

290,275

297,441

326,492

291,171

–1.1

7.0

 

Solar

534

575

550

508

606

13.5

0.0

 

Geothermal

14,424

14,811

14,692

14,568

14,839

2.9

0.4

 

Water

267,271

259,929

263,763

282,689

241,319

–9.7

5.8

 

Wind

11,187

14,144

17,811

26,589

32,143

187.3

0.8

Biomass

62,140

61,749

62,714

63,425

64,073

3.1

1.5

 

Agricultue Crop Byproducts

725

747

675

661

726

0.2

0.0

 

Black Liquor

18,660

17,782

18,230

18,268

18,231

–2.3

0.4

 

Landfill Gas

5,077

5,128

5,135

5,677

6,200

22.1

0.1

 

Municipal Solid Waste

15,102

14,824

14,883

15,137

15,234

0.9

0.4

 

Other Biomass Gases

1,088

840

758

788

854

–21.4

0.0

 

Other Biomass Liquid

8

12

7

10

11

44.4

0.0

 

Other Biomass Solid

345

408

369

315

296

–14.3

0.0

 

Sludge Waste

263

209

200

181

229

–12.9

0.0

 

Wood Waste Liquids

647

315

197

154

72

–88.8

0.0

 

Wood Waste Solids

18,222

19,479

20,254

20,227

20,212

10.9

0.5

Petroleum

102,734

100,040

100,095

44,655

49,956

–51.4

1.2

 

Distillate Fuel Oil

15,169

10,660

11,198

7,236

8,423

–44.5

0.2

 

Jet Fuel

60

277

338

302

597

902.3

0.0

 

Kerosene

439

422

517

185

482

9.8

0.0

 

Residual Fuel Oil

85,940

87,551

87,189

36,054

39,561

–54.0

1.0

 

Waste Oil

1,127

1,129

853

877

893

–20.7

0.0

Residual

39,504

45,289

44,648

49,731

44,948

13.8

1.8

 

Blast Furnace Gas

2,826

3,513

3,689

3,574

3,383

19.7

0.1

 

Municipal Solid Waste (non-biogenic)

*

*

*

6,661

6,666

**

0.2

 

Other Gas

12,758

13,232

12,613

12,469

11,999

–6.0

0.3

 

Other

5,024

5,863

4,124

3,925

3,697

–26.4

0.1

 

Petroleum Coke

16,672

20,731

22,427

19,709

15,752

–5.5

0.4

 

Purchased Steam

1,097

816

625

2,139

2,264

106.3

0.1

 

Tires

1,128

1,134

1,171

1,254

1,188

5.3

0.0

Total All Fuel Types

3,883,185

3,970,555

4,055,423

4,064,702

4,159,514

7.1

100.0

Year-Over-Year Percent Change

 

2.25

2.14

0.23

2.33

   

* Reported as mixed municipal solid waste.

** Added to municipal solid waste-biogenic (MSB) for percentage calculation.

Table 4. 

Carbon dioxide emissions by U.S. electric power plants by energy source, 2003–2007.

Fuel Group and Energy Source

2003

2004

2005

2006

2007

Change 2003–07

Share 2007

 

(1,000 metric tons)

(%)

(%)

Coal

1,927,847

1,939,598

1,933,992

1,954,332

1,987,563

3.1

78.1

 

Bituminous and Anthracite Coal

1,002,095

968,583

986,591

982,394

985,365

–1.7

38.7

 

Lignite Coal

100,958

94,349

52,427

95,244

90,281

–10.6

3.5

 

Coal-Based Synfuel

52,449

66,406

64,158

52,197

66,462

26.7

2.6

 

Sub-Bituminous Coal

761,676

797,903

816,458

808,874

829,454

8.9

32.6

 

Waste / Other Coal

10,669

12,358

14,359

15,623

16,001

50.0

0.6

Natural Gas & Propane

304,670

333,614

354,359

375,018

409,854

34.5

16.1

 

Natural Gas

304,659

333,597

354,348

375,007

409,828

34.5

16.1

 

Propane

11

17

11

11

26

134.6

0.0

Biomass

73,967

75,700

70,677

66,292

69,462

–6.1

2.7

 

Agricultue Crop Byproducts

1,253

1,115

1,109

1,122

1,270

1.4

0.0

 

Black Liquor

21,335

23,069

18,448

19,744

21,509

0.8

0.8

 

Landfill Gas

3,439

3,644

3,483

4,001

4,426

28.7

0.2

 

Municipal Solid Waste

21,932

22,207

22,052

13,679

13,935

–13.2

0.7

 

Other Biomass Gases

597

487

511

519

539

–9.7

0.0

 

Other Biomass Liquid

6

6

3

5

5

–17.8

0.0

 

Other Biomass Solid

479

671

528

507

510

6.4

0.0

 

Sludge Waste

329

381

270

214

267

–19.0

0.0

 

Wood Waste Liquids

789

201

150

339

103

–87.0

0.0

 

Wood Waste Solids

23,808

23,920

24,024

26,161

26,897

13.0

1.1

Petroleum

85,062

82,894

82,691

37,405

42,067

–50.5

1.7

 

Distillate Fuel Oil

12,604

8,789

9,000

5,685

7,049

–44.1

0.3

 

Jet Fuel

58

200

254

213

377

553.2

0.0

 

Kerosene

354

374

421

168

412

16.5

0.0

 

Residual Fuel Oil

71,178

72,493

72,275

30,554

33,474

–53.0

1.3

 

Waste Oil

868

1,038

742

784

755

–13.0

0.0

Residual

28,770

35,573

36,524

39,747

34,607

20.3

1.4

 

Blast Furnace Gas

2,188

2,281

2,702

2,885

2,472

13.0

0.1

 

Municipal Solid Waste (non-biogenic)

*

*

*

5,065

5,105

**

0.2

 

Other Gas

7,400

9,215

8,077

8,124

7,662

3.5

0.3

 

Petroleum Coke

18,040

22,835

24,447

22,203

17,936

–0.6

0.7

 

Tires

1,142

1,242

1,298

1,470

1,431

25.3

0.1

Non-Biomass Renewables / Geothermal

2,283

2,344

2,325

2,305

2,348

2.9

0.1

Total All Sources

2,422,599

2,469,723

2,480,568

2,475,098

2,545,900

5.1

100.0

Annual Percent Change

 

1.95

0.44

–0.22

2.86

   

* Reported as mixed municipal solid waste.

** Added to municipal solid waste-biogenic (MSB) for percentage calculation.

Table 5. 

Emission ratios by U.S. power plants, 2003 and 2007, and percent change.

State

Electricity Generation, 2007

Carbon Dioxide Emissions, 2007

Emission Ratio, 2003

Emission Ratio, 2007

Change Emission Ratio 2003–07

 

(gigawatt–hours)

(1,000 metric tons)

(metric tons per megawatt–hour)

(metric tons per megawatt–hour)

(%)

Vermont

6,382

576

0.14

0.09

–37

Nevada

31,888

16,615

0.70

0.52

–26

Washington

106,079

14,078

0.16

0.13

–18

Oklahoma

72,253

51,036

0.80

0.71

–12

New York

146,499

53,821

0.41

0.37

–10

Nebraska

32,957

20,866

0.71

0.63

–10

Iowa

49,760

41,351

0.91

0.83

–9

New Hampshire

23,413

8,425

0.39

0.36

–8

Virginia

78,594

42,239

0.58

0.54

–8

Florida

225,832

132,280

0.63

0.59

–7

New Mexico

35,953

31,800

0.96

0.88

–7

Connecticut

33,494

10,953

0.35

0.33

–6

New Jersey

63,088

20,888

0.35

0.33

–6

Kansas

50,080

39,179

0.83

0.78

–6

Colorado

52,954

42,872

0.86

0.81

–6

Massachusetts

47,513

26,601

0.59

0.56

–5

Minnesota

53,611

36,949

0.73

0.69

–5

Mississippi

49,880

29,216

0.61

0.59

–4

Wisconsin

63,402

47,227

0.78

0.74

–4

Ohio

156,069

130,774

0.87

0.84

–4

Utah

43,691

38,355

0.91

0.88

–4

Missouri

91,147

77,281

0.87

0.85

–3

Wyoming

45,581

45,180

1.03

0.99

–3

Rhode Island

7,049

2,997

0.43

0.42

–2

Arkansas

55,074

30,839

0.57

0.56

–2

Pennsylvania

227,278

131,161

0.59

0.58

–2

Texas

405,582

258,103

0.65

0.64

–1

Maryland

49,968

31,159

0.63

0.62

–1

Montana

28,491

20,199

0.71

0.71

0

Arizona

113,022

55,854

0.49

0.49

0

Maine

15,660

8,348

0.53

0.53

0

Louisiana

92,766

54,669

0.59

0.59

0

Michigan

120,282

80,972

0.67

0.67

0

West Virginia

93,940

84,886

0.90

0.90

0

Indiana

130,728

124,119

0.94

0.95

1

North Dakota

30,820

31,573

1.02

1.02

1

Idaho

11,319

2,044

0.18

0.18

2

Kentucky

97,477

93,899

0.94

0.96

2

Illinois

200,332

101,608

0.49

0.51

3

Alabama

144,575

91,482

0.61

0.63

4

Hawaii

11,714

9,703

0.80

0.83

4

Georgia

145,394

97,958

0.64

0.67

5

Delaware

8,510

7,836

0.88

0.92

5

South Carolina

103,911

44,712

0.41

0.43

6

Tennessee

94,930

57,854

0.58

0.61

6

California

214,099

67,108

0.29

0.31

8

North Carolina

130,239

79,783

0.57

0.61

8

Oregon

53,578

11,197

0.`9

0.21

9

Alaska

6,888

4,128

0.55

0.60

9

South Dakota

5,664

3,061

0.46

0.54

16

Footnotes

1.

This document is FE796, one of a series of the Food and Resource Economics Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 2009. Reviewed January2012. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Alan W. Hodges, extension scientist, and Mohammad Rahmani, coordinator of economic analysis, Food and Resource Economics Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.