On-Farm Renewable 

Energy Production 

Survey (2009) 

Volume 3 • Special Studies • Part 6 

AC-07-SS-6

Issued February 2011 

United States Department of Agriculture 

Tom Vilsack, Secretary 

National Agricultural Statistics Service 

Cynthia Z.F. Clark, Administrator 
 

 
 

2007 CENSUS OF AGRICULTURE CONTENTS III

USDA, National Agricultural Statistics Service 

Contents

Page 

Introduction .................................................................................................................................. V 

TABLES

1. Farms Reporting Wind Turbines, Capacity, Installation Cost, Percent Funded by 

 Outside Sources, and Year of Installation: 2009 .................................................................. 1

2. Farms Reporting Methane Digesters, Number of Digesters, Methane Produced, 

 Installation Cost, Percent Funded by Outside Sources, and Year of Installation: 2009 ....... 2

3. Farms Reporting Photovoltaic (PV) and Thermal Solar Panels by Type, Capacity, 

 Installation Cost, Percent Funded by Outside Sources, and Year of Installation: 2009 ....... 3

4. Farms Reporting Energy Savings, Energy Audits, and/or Federal Funding: 2009 .............. 4

APPENDICES

A. Statistical Methodology ........................................................................................................ A-1

B. General Explanation and Report Form ................................................................................. B-1
 

 
 

2007 CENSUS OF AGRICULTURE INTRODUCTION V

USDA, National Agricultural Statistics Service 

Introduction

BACKGROUND 

The 2009 On-Farm Renewable Energy Production 

Survey (OREPS) is a follow-on survey to the 2007 

Census of Agriculture. It is the first on-farm 

renewable energy production survey conducted on 

the national level by the U.S. Department of 

Agriculture (USDA), National Agricultural Statistics 

Service (NASS). 

The 2009 OREPS provides additional information on 

energy produced by wind turbines, solar panels, and 

methane digesters that were in operation on farms in 

2009. Wind turbines located on farm operations 

under a wind rights lease agreement are considered 

commercial and were excluded from this survey. 

Methane digesters not owned and operated by the 

farm operation were not included in the survey. 

This energy survey provides an inventory of farmgenerated energy practices with detailed data relating 

to the category or type of energy produced (wind, 

solar, and manure/methane digester), installation 

cost, percent of cost from outside funding, year 

installed, and total amount of utility savings from the 

use of on-farm renewable energy production. 

USES OF SURVEY DATA 

Producers, universities, legislators, utility providers, 

farm businesses, etc. are in need of renewable energy 

production and economic data in order to assess the 

growth and viability of new energy sources and 

make important marketing, business, and policy 

decisions. The production of on-farm renewable 

energy can provide cost saving alternatives for 

America‟s farmers and ranchers. The information 

gathered will help in the continued development of 

this expanding agricultural industry. 

AUTHORITY 

The census of agriculture is required by law under 

the “Census of Agriculture Act of 1997,” Public Law 

105-113 (Title 7, United States Code, Section 

2204g). The law authorizes the Secretary of 

Agriculture to conduct surveys deemed necessary to 

furnish annual or other data on the subjects covered 

by the census. The 2009 On-Farm Renewable 

Energy Production Survey was conducted under the 

provisions of this section. 

RENEWABLE ENERGY DEFINITION 

Renewable energy is energy that comes from natural 

sources (sun, wind, water, biomass, and geothermal)

and is renewable or naturally replenished. 

Renewable energy differs not only from fossil 

energy sources such as petroleum, gas, and coal, but 

also from nuclear energy. 

REFERENCE PERIOD 

Energy production and savings were measured for 

the 2009 calendar year. Installation costs and outside 

funding were as of time of installation. 

TABLES AND APPENDICES 

Tables. Tables 1 through 4 provide data from the 

survey at the U.S. and State level. 

Appendix A. Provides information about data 

collection and data processing activities and 

discusses the statistical methodology used in 

conducting and evaluating the survey. Tables A and 

B provide statistical precision estimates for selected 

survey items. 

Appendix B. Includes definitions of specific terms 
 

VI INTRODUCTION 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

and phrases used in this publication. It also provides 

facsimiles of the report form and instruction sheet 

used to collect data. 

RESPONDENT CONFIDENTIALITY 

In keeping with the provisions of Title 7 of the 

United States Code, no data are published that would 

disclose information about an individual operation. 

All tabulated data are subjected to an extensive 

disclosure review prior to publication. Any tabulated 

item that identifies data reported by a respondent or 

allows a respondent‟s data to be closely estimated or 

derived is suppressed and coded with a „D‟. The 

number of operations reporting an item is not 

considered confidential information and is provided 

even though other information may be withheld. 

DATA PRODUCTS AND CUSTOM 

TABULATIONS 

The 2009 On-Farm Renewable Energy Production 

Survey data, as well as the 2007 Census of 

Agriculture Volume 1 Geographic Area Series and 

related reports, are available on the NASS website at 

www.nass.usda.gov/. 

Custom-designed tabulations may be developed 

when data are not published elsewhere. These 

tabulations are developed to individual user 

specifications on a cost-reimbursable basis and 

shared with the public. The census Volume 1 on a 

downloadable desktop query tool and the census 

Quick Stats are alternative data sources that should 

be investigated before requesting a custom 

tabulation. 

All custom tabulations are subject to a thorough 

disclosure review prior to release to prevent the 

disclosure of any individual respondent data. 

Requests for custom tabulations can be submitted via 

the internet from the NASS home page, by mail, or 

by e-mail to: 

DataLab 

National Agricultural Statistics Service 

Room 6436A, Stop 2054 

1400 Independence Ave, S.W. 

Washington, D.C. 20250-2054

or 

Datalab@nass.usda.gov

ABBREVIATIONS AND SYMBOLS 

The following abbreviations and symbols are used 

throughout the tables: 

- Represents zero. 

(D) Withheld to avoid disclosing data for 

individual farms. 

(Z) Less than half of the unit shown. 

(NA) Not available. 

(X) Not applicable. 

W Watt. 

kW Kilowatt. 
 

2007 CENSUS OF AGRICULTURE 2009 ON-FARM RENEWABLE ENERGY PRODUCTION SURVEY 1

USDA, National Agricultural Statistics Service 

Table 1. Farms Reporting Wind Turbines, Capacity, Installation Cost, Percent Funded by Outside 

Sources, and Year of Installation: 2009

State Farms Number of

turbines

Average per turbine Percent of

installation

cost funded

by outside

sources 1

Year wind turbines installed 2

(number of turbines)

Rated

generating

capacity 1

(kilowatts)

Installation

cost 1

(dollars)

Prior to

2000

2000-

2004

2005-

2009

ALL WIND, TOTAL

United States ............................

SMALL WIND (1-100kW)

United States ............................

Alabama ...................................

Alaska .......................................

Arizona .....................................

Arkansas ..................................

California ..................................

Colorado ...................................

Connecticut ..............................

Delaware ..................................

Florida ......................................

Georgia .....................................

Hawaii .......................................

Idaho ........................................

Illinois .......................................

Indiana ......................................

Iowa ..........................................

Kansas .....................................

Kentucky ...................................

Louisiana ..................................

Maine ........................................

Maryland ...................................

Massachusetts .........................

Michigan ...................................

Minnesota .................................

Mississippi ................................

Missouri ....................................

Montana ...................................

Nebraska ..................................

Nevada .....................................

New Hampshire ........................

New Jersey ...............................

New Mexico ..............................

New York ..................................

North Carolina ..........................

North Dakota ............................

Ohio ..........................................

Oklahoma .................................

Oregon .....................................

Pennsylvania ............................

Rhode Island ............................

South Carolina ..........................

South Dakota ............................

Tennessee ................................

Texas ........................................

Utah ..........................................

Vermont ....................................

Virginia .....................................

Washington ..............................

West Virginia ............................

Wisconsin .................................

Wyoming ..................................

1,420

1,406

3

8

63

7

134

98

1

-

5

4

43

39

28

49

39

18

1

2

32

2

22

34

99

3

21

63

7

8

11

3

28

58

12

5

44

20

37

26

2

-

11

9

102

31

43

11

50

4

46

20

1,845

1,831

4

8

78

11

160

147

(D)

-

5

4

67

44

36

58

48

20

(D)

(D)

34

(D)

30

47

144

3

28

78

9

10

11

3

34

65

12

9

57

22

63

27

(D)

-

13

13

148

41

54

13

67

4

59

35

(X)

6

(D)

1

1

2

3

3

(D)

-

1

(D)

1

4

5

2

8

6

(D)

(D)

5

(D)

7

2

20

1

3

3

1

1

3

8

1

5

2

(D)

2

2

1

3

(D)

-

4

(D)

4

1

3

1

19

5

8

2

(X)

12,972

(D)

4,394

2,768

5,800

13,955

4,581

(D)

-

5,250

(D)

1,799

12,778

11,448

7,870

23,840

10,084

(D)

(D)

17,353

(D)

43,218

9,981

37,647

4,467

7,779

6,293

1,563

1,455

9,850

47,518

4,807

22,254

12,800

15,778

11,257

4,156

3,209

7,148

(D)

-

19,064

8,177

8,493

2,562

16,847

2,971

12,669

44,400

15,329

4,648

(X)

49

-

-

51

-

50

-

-

-

-

-

-

25

(D)

(D)

29

-

-

-

(D)

(D)

45

(D)

51

-

(D)

62

-

-

-

63

-

64

-

(D)

39

(D)

(D)

(D)

(D)

-

-

-

-

-

46

35

(D)

-

33

(D)

(D)

356

-

3

15

5

38

26

-

-

-

-

16

9

(D)

4

17

5

-

-

8

-

5

4

15

-

(D)

9

-

(D)

6

-

10

12

(D)

5

15

(D)

19

4

(D)

-

(D)

-

19

7

3

-

30

(D)

22

(D)

535

532

-

-

30

(D)

60

38

-

-

-

4

23

12

(D)

9

8

5

-

-

11

-

-

10

46

-

(D)

33

5

5

(D)

(D)

5

21

(D)

(D)

13

10

22

4

-

-

(D)

8

46

10

33

4

12

-

18

(D)

(D)

899

4

5

30

(D)

52

80

(D)

-

5

-

28

23

28

43

21

10

(D)

(D)

15

(D)

25

33

83

3

20

36

4

(D)

(D)

(D)

17

32

7

(D)

29

(D)

22

15

-

-

8

5

81

18

18

9

23

(D)

17

29

See footnote(s) at end of table. --continued
 

2 2009 ON-FARM RENEWABLE ENERGY PRODUCTION SURVEY 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

Table 1. Farms Reporting Wind Turbines, Capacity, Installation Cost, Percent Funded by Outside 

Sources, and Year of Installation: 2009 - (continued)

State Farms Number of

turbines

Average per turbine Percent of

installation

cost funded

by outside

sources 1

Year wind turbines installed 2

(number of turbines)

Rated

generating

capacity 1

(kilowatts)

Installation

cost 1

(dollars)

Prior to

2000

2000-

2004

2005-

2009

LARGE WIND (>100kW)

United States ...........................

Iowa .........................................

Other States 3..........................

14

9

5

14

9

5

1,035

1,359

453

1,339,143

1,784,889

536,800

39

(D)

(D)

(D)

-

(D)

3

3

-

(D)

6

(D)

1 Only includes positive reported data. Operations that reported zero or failed to report are not included.

2 Numbers may not add to total number of turbines. Only includes operations reporting year installed.

3 Other States include Kansas, Minnesota, and Montana.

Table 2. Farms Reporting Methane Digesters, Number of Digesters, Methane Produced, Installation 

Cost, Percent Funded by Outside Sources, and Year of Installation: 2009

State Farms

Number of

methane

digesters

Average per methane digester Percent of

installation

cost funded

by outside

sources 1

Year methane digesters installed 2

(number of digesters)

Methane

produced 1

(cubic feet)

Installation

cost 1

(dollars)

Prior to

2000

2000-

2004

2005-

2009

United States .........

California ................

Michigan ................

Minnesota ..............

New York ...............

Pennsylvania .........

Vermont .................

Wisconsin ..............

Other States 3........

121

14

5

5

16

13

8

21

39

140

14

10

6

16

16

8

25

45

30,515,800

29,194,314

36,923,333

69,105,120

18,611,675

18,951,843

(D)

(D)

26,034,140

1,718,562

1,794,444

1,322,222

3,123,333

1,611,206

642,188

1,718,750

1,608,924

2,181,189

48

47

(D)

(D)

36

58

31

19

76

11

(D)

-

(D)

-

(D)

(D)

-

4

22

-

-

(D)

3

(D)

-

6

8

86

(D)

9

(D)

10

9

(D)

18

23

1 Only includes positive reported data. Operations that reported zero or failed to report are not included.

2 Numbers may not add to total number of digesters. Only includes operations reporting year installed.

3 Other States include Colorado, Connecticut, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Maryland, Mississippi, Missouri, Montana, Nebraska, North 

Carolina, Ohio, Oklahoma, Oregon, South Dakota, Tennessee, Texas, Washington, and Wyoming.
 

2007 CENSUS OF AGRICULTURE 2009 ON-FARM RENEWABLE ENERGY PRODUCTION SURVEY 3

USDA, National Agricultural Statistics Service 

Table 3. Farms Reporting Photovoltaic (PV) and Thermal Solar Panels by Type, Capacity, Installation 

Cost, Percent Funded by Outside Sources, and Year of Installation: 2009

State Farms

Farms reporting 1Average per farm Percent of

installation

cost funded

by outside

sources 1

Year solar panels installed 2

(number of solar panels)

PV solar

panels

Thermal

solar panels

PV rated

generating

capacity 1

(watts)

Installation

cost 1

(dollars)

Prior to

2000

2000-

2004

2005-

2009

United States .......................

Alabama ..............................

Alaska ..................................

Arizona ................................

Arkansas .............................

California .............................

Colorado ..............................

Connecticut .........................

Delaware .............................

Florida .................................

Georgia ................................

Hawaii ..................................

Idaho ...................................

Illinois ..................................

Indiana .................................

Iowa .....................................

Kansas ................................

Kentucky ..............................

Louisiana .............................

Maine ...................................

Maryland ..............................

Massachusetts ....................

Michigan ..............................

Minnesota ............................

Mississippi ...........................

Missouri ...............................

Montana ..............................

Nebraska .............................

Nevada ................................

New Hampshire ...................

New Jersey ..........................

New Mexico .........................

New York .............................

North Carolina .....................

North Dakota .......................

Ohio .....................................

Oklahoma ............................

Oregon ................................

Pennsylvania .......................

Rhode Island .......................

South Carolina .....................

South Dakota .......................

Tennessee ...........................

Texas ...................................

Utah .....................................

Vermont ...............................

Virginia ................................

Washington .........................

West Virginia .......................

Wisconsin ............................

Wyoming .............................

7,968

33

16

255

41

1,906

504

26

4

88

32

520

131

58

127

40

116

67

13

97

21

63

75

73

23

93

238

65

51

49

138

258

156

104

29

130

187

332

173

12

20

55

66

573

133

110

83

205

27

176

176

7,236

24

15

242

37

1,825

445

23

4

69

30

469

121

45

112

34

93

56

13

87

19

50

53

51

23

84

226

65

51

35

138

241

140

67

28

115

167

294

160

10

18

45

59

541

125

103

70

188

24

134

168

1,835

13

1

41

5

385

117

10

-

39

4

213

21

18

27

19

36

21

2

27

11

22

27

34

1

22

35

7

6

26

24

38

29

55

2

23

37

97

37

6

5

12

9

67

20

28

16

39

5

78

18

4,449

865

865

2,002

833

11,229

1,654

4,173

15,500

2,162

3,625

1,790

916

4,575

543

1,988

408

776

876

1,680

2,665

3,678

841

1,409

706

1,022

988

742

1,832

1,641

14,081

1,261

2,501

1,015

429

1,614

428

3,002

1,750

(D)

(D)

696

1,065

783

1,211

1,304

869

1,547

521

2,484

1,275

31,947

6,948

9,134

19,992

7,502

78,910

16,879

29,571

101,250

12,223

28,545

16,665

12,524

39,018

5,262

17,791

4,607

6,305

10,970

13,892

24,201

27,624

7,416

11,178

11,593

9,429

9,180

5,632

21,971

16,173

112,855

12,888

21,661

10,198

5,048

12,122

4,612

22,147

20,699

30,960

5,047

7,470

8,657

7,692

14,573

15,510

12,868

10,377

8,166

17,607

10,362

44

47

42

50

(D)

41

47

52

54

40

66

28

55

44

-

47

55

29

(D)

26

26

53

30

45

(D)

54

48

57

33

(D)

64

39

59

47

47

53

45

44

44

(D)

54

49

29

42

51

34

22

16

(D)

27

42

18,881

25

66

1,200

238

4,242

1,843

(D)

-

148

22

1,498

442

344

132

42

186

62

(D)

330

115

154

198

193

14

114

562

149

152

413

216

675

315

159

17

185

164

793

122

18

42

44

199

511

183

444

104

588

52

866

287

45,028

9

(D)

1,271

47

27,544

1,462

54

-

54

76

1,790

220

803

131

142

81

36

(D)

216

(D)

173

64

133

58

63

565

232

166

-

2,204

690

459

163

40

781

210

1,046

290

(D)

28

109

114

806

580

272

186

740

56

424

411

108,532

96

79

1,795

132

64,328

2,520

428

(D)

488

378

4,189

396

384

323

380

172

387

74

1,161

298

959

278

240

48

360

882

317

542

416

9,631

1,000

1,867

388

68

454

351

3,284

2,048

236

53

148

396

1,850

504

582

360

872

(D)

1,333

793

1 Only includes positive reported data. Operations that reported zero or failed to report are not included.

2 Only includes operations reporting year installed.
 

4 2009 ON-FARM RENEWABLE ENERGY PRODUCTION SURVEY 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

Table 4. Farms Reporting Energy Savings, Energy Audits, and/or Federal Funding: 2009

[Only operations that reported wind turbines, methane digesters, and/or solar panels]

State

Total farms

reporting wind

turbines, digesters,

and/or solar panels

Average dollars

saved on

2009 utility bills

per farm 1

Performed

energy audit

(farms)

Received

federal funding

(farms)

United States ......................

Alabama ..............................

Alaska .................................

Arizona ................................

Arkansas .............................

California .............................

Colorado .............................

Connecticut .........................

Delaware .............................

Florida .................................

Georgia ...............................

Hawaii .................................

Idaho ...................................

Illinois ..................................

Indiana ................................

Iowa ....................................

Kansas ................................

Kentucky .............................

Louisiana ............................

Maine ..................................

Maryland .............................

Massachusetts ....................

Michigan .............................

Minnesota ...........................

Mississippi ..........................

Missouri ..............................

Montana ..............................

Nebraska ............................

Nevada ...............................

New Hampshire ..................

New Jersey .........................

New Mexico ........................

New York ............................

North Carolina .....................

North Dakota .......................

Ohio ....................................

Oklahoma ...........................

Oregon ................................

Pennsylvania ......................

Rhode Island .......................

South Carolina ....................

South Dakota ......................

Tennessee ..........................

Texas ..................................

Utah ....................................

Vermont ..............................

Virginia ................................

Washington .........................

West Virginia .......................

Wisconsin ...........................

Wyoming .............................

8,569

33

17

259

42

1,956

518

28

4

91

32

522

147

76

152

74

125

68

13

108

24

78

94

157

25

102

253

68

51

49

139

260

202

107

32

148

200

342

196

13

20

63

71

624

133

128

85

217

31

214

178

2,406

1,006

1,393

2,461

1,070

4,395

1,415

2,061

2,375

1,013

872

2,125

1,487

1,688

518

1,573

689

831

(D)

1,221

1,125

917

529

1,364

490

547

1,737

1,117

2,084

1,162

2,641

2,080

5,067

1,083

803

2,000

1,037

1,251

4,534

3,138

(D)

555

921

1,198

2,188

2,948

920

1,181

606

1,506

1,330

613

1

2

8

2

237

14

8

2

8

2

10

5

3

2

7

-

3

1

13

3

37

13

18

1

3

25

1

-

8

30

1

23

6

-

7

2

21

10

1

-

1

2

14

4

11

1

2

7

30

3

1,101

6

3

46

2

282

48

3

3

5

10

19

8

14

7

22

11

3

-

9

4

19

8

29

1

12

47

7

1

2

26

35

40

7

13

9

28

46

52

2

2

11

4

32

5

27

8

14

9

49

51

1 Only includes positive reported data. Operations that reported zero or failed to report are not included.
 

2007 CENSUS OF AGRICULTURE APPENDIX A A-1

USDA, National Agricultural Statistics Service 

Appendix A.

Statistical Methodology

THE SURVEY POPULATION 

The target population for the 2009 On-Farm 

Renewable Energy Production Survey (OREPS) was 

all farms and ranches that selected yes to the 

question “At any time during 2007, did this 

operation generate energy or electricity on the farm 

using wind or solar technology, methane digester, 

etc?” on the 2007 Census of Agriculture. 

Operations that were listed on the U.S. 

Environmental Protection Agency‟s AgStar site 

(http://www.epa.gov/agstar/projects/index.html) as 

having a methane digester project that was operable 

in 2009 and earlier were also included in the sample 

population. 

DATA COLLECTION 

Method of Enumeration 

The 2009 OREPS was conducted primarily by mail. 

It was supplemented with electronic data reporting 

via the internet and data collected by telephone and 

personal enumeration. 

Report Form 

A four page report form was designed to capture data 

for number of on-farm renewable energy production 

devices, installation costs, sales to the grid, and 

utility savings. The main focus of the 2009 OREPS 

was to provide detailed information on wind 

turbines, solar panels and methane digesters. The 

“other forms of energy produced” question in 

Section 5 of the OREPS report form was primarily 

for clarification and was not summarized or 

published. The “other solar powered devices (fence 

chargers)” question in Section 3 was included to 

prevent misreporting of solar panels versus small 

solar powered devices. These devices were included 

in the 2007 Census of Agriculture published count of 

farms having renewable energy producing devices 

but were not included in the published OREPS solar 

panel section. The questions pertaining to energy 

sales were not summarized or published in this first 

energy release due to reporting errors. There was 

confusion between actual sales and net metering. On 

future energy surveys, sales questions will be 

clarified and additional net metering questions will 

be asked. 

Report Form Mailings and Respondent 

Follow-up

The 2009 On-Farm Renewable Energy Production 

Survey report form mail packet was mailed from the 

Census Bureau‟s National Processing Center (NPC) 

at Jeffersonville, IN on May 3, 2010. The mail 

packet included a labeled report form, an instruction 

sheet, a letter requesting prompt response with 

electronic data reporting instructions, and a return 

envelope to NPC for data capture. The report form 

carried a return due date of May 24, 2010. A second 

mailing to nonrespondents took place from NPC on 

June 4, 2010. 

Telephone follow-up interviews to nonrespondents 

took place from June 20 to July 9, 2010 from NASS 

Data Collection Centers. A process was used to 

exclude operations from receiving a follow-up 

telephone call if their report form was received in the 

mail. 

Data collection for the 2009 OREPS was coordinated 

with other NASS agricultural surveys. In some cases, 

if an operation was selected for multiple surveys, 

NPC mailed the materials to NASS field offices. 

Field office personnel then were responsible for 

collecting the data and completing other survey 

report forms in an effort to reduce the number of 

contacts and respondent burden. 
 

A-2 APPENDIX A 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

REPORT FORM PROCESSING 

Data Capture

All report forms returned to NPC were immediately 

checked in using bar codes printed on the mail label 

and were removed from follow-up mailings. All 

forms were reviewed prior to data keying to identify 

inconsistencies and ensure the data could be keyed. 

Major inconsistencies, respondent remarks, and 

blank forms were reviewed by analysts and adjusted 

prior to keying. In some cases, report forms were 

mailed to field offices for further editing. All forms 

with any data were scanned and an image was 

created for each page of the report form. After 

images were created, the data were keyed directly 

from the report form. 

Data Editing and Analysis 

Data from each report form were processed through 

a computer edit which flagged inconsistent entries. 

Each report form with a flagged entry was reviewed 

by an analyst. Action was required for any record 

with reported data that were obviously incorrect. In 

some cases, respondents may have failed to provide 

all of the information requested, only indicating the 

presence of an item but not the amount. Only 

number of wind turbines and methane digesters were 

coded for machine imputation. Percents and averages 

of positive reported data were used for all other 

items. 

After the initial edit, an automated imputation 

program supplied missing wind turbine and digester 

numbers based on State or national averages. A postimputation computer edit was performed to ensure 

imputation actions provided acceptable results. 

Instances where imputed data failed edit checks were 

referred to analysts for corrective action. 

The computer edit ensured the data on a report form 

were internally consistent. An analysis tool was 

provided to examine the data across records to check 

for distributional irregularities and data outliers. 

Analysts corrected suspect data when necessary and 

re-edited the record. 

ESTIMATION 

Nonresponse Weighting 

While effort was expended to obtain a response from 

each farm, a complete set of responses was not 

achieved. Nonresponse can lead to biases in 

published estimates because the information 

concerning on-farm energy production of the 

nonresponding farms could not be factored into the 

estimates. Estimates of totals, for example, will be 

biased low. It is necessary to reduce this bias 

through the use of a procedure called nonresponse 

weight adjustment. Nonresponse weight adjustment 

gives more weight to the data reported by responding 

farms in an effort to account for the data that would 

have been reported by the nonresponding farms. 

This will increase the estimates of totals obtained by 

the respondents and reduce this bias. 

Most of the estimates published from the 2009 

OREPS are ratios of estimated totals. The potential 

for bias exists for these estimated ratios, although it 

is difficult to predict whether the bias is upward or 

downward. Nevertheless, nonresponse adjustments 

were calculated and factored into the ratio estimates 

as well. 

Conceptually, each farm on the mail list begins the 

survey with a weight of one. In other words, if each 

farm on the list would provide the requested data, the 

data could be simply added up to estimate the total. 

In the presence of nonresponse, adjustments are 

computed and applied to the initial weights of the 

responding farms resulting in a nonresponse adjusted 

weight greater than 1 for these farms. The initial 

weight of each nonresponding farm is adjusted to 

zero. The adjustments are computed in a manner 

that requires the sum of the nonresponse-adjusted 

weights across the responding farms on the mail list 

to equal the sum of the initial weights across all 

farms on the mail list. 

If the total number of farms on the mail list is N, the 

sum of the initial weights across all farms on the 

mail list equals N, because the initial weight for each 

farm on the list is 1. The sum of the nonresponse- 
 

2007 CENSUS OF AGRICULTURE APPENDIX A A-3

USDA, National Agricultural Statistics Service 

adjusted weights across all responding farms on the 

mail list must equal N. In fact, the sum of the 

nonresponse-adjusted weights across all farms on the 

list would sum to N as well because the nonresponse 

adjusted weight of nonresponding farms is set to 0. 

Weight-Adjustment Groups 

To compute nonresponse adjustments, each record 

on the mail list is first placed in a weight-adjustment 

group. The groups are defined in such a way that all 

farms that reside in the same group appear to share 

similarities with respect to the characteristics used to 

define the group. It is necessary that the 

characteristics by which the weight-adjustment 

groups are defined be available for responding and 

nonresponding farms alike. Therefore, it was not 

possible to define weight-adjustment groups using 

data collected via the survey. Information used to 

define the groups was obtained from historical 

information maintained on the mail list and available 

for each farm. 

The information used to create the weightadjustment groups was a measure of general farm 

sales (GFS), expressed in total dollars. This measure 

is available for all farms on the mail list. The basic 

definition of the weight-adjustment groups is given 

below: 

Weight 

Adjustment 

Definition Group ID 

GFS<= $50,000 10

$50,000< GFS <= $250,000 20

$250,000< GFS <=$500,000 30

$500,000< GFS <= $1,000,000 40

$1,000,000 < GFS <= $5,000,000 50

$5,000,000 < GFS 60

Methane Digester Farms 900

Farms on the mail list were placed in mutually 

exclusive groups based on the farm‟s GFS. One 

additional weight-adjustment group was composed 

of farms believed to possess a methane digester. 

These farms are generally economically large but 

were placed in the group 900 without regard to the 

GFS. Weight-adjustment groups were created and 

weight adjustments were carried out separately for 

each state. 

To ensure there were sufficient numbers of 

responding farms in each group, some collapsing of 

weighting groups occurred, resulting in some States 

having more weight adjustment groups than others. 

Nonresponse-Adjustment Computation 

A separate nonresponse adjustment is calculated 

within each weight-adjustment group. All 

responding records within each group will receive 

the same nonresponse adjusted weight. The 

nonresponse-adjustment is obtained by dividing the 

total number of farms contained in a group by the 

number of responding farms in the group. If the total 

number of farms in the group is 50 and the number 

of responding farms in the group is 40, the 

nonresponse-adjustment for the responding farms is 

50/40 or 1.25. The nonresponse-adjusted weight for 

all responding farms in the group is the product of 

the survey weight and the nonresponse adjustment of 

1.25. This is simply (1 x 1.25) or 1.25. Note that 

1.25 x 40 = 50, the total number of farms in the 

group.

The assumption being made is that within each 

weight-adjustment group, the data the 

nonrespondents would have provided had they 

responded is similar to the data provided by the 

respondents. This assumption is made somewhat 

more plausible by the fact that farms in the same 

group share similar characteristics with respect to the 

information used to define the group- the GFS. 

Coverage Weighting Adjustments 

The target population for the 2009 OREPS was the 

set of all farms in the United States producing at 

least $1,000 worth of raw agricultural commodities 

and producing on-farm renewable energy in 2009. 

Realistically, it is a nearly impossible task to 

compose a list of farms that is complete. Due to this 

incompleteness of the 2009 OREPS mail list, 

estimates produced from it, even if perfectly 

corrected to account for nonresponse, will still be 

downward biased because farms not on the list 
 

A-4 APPENDIX A 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

would not have any representation. This bias due to 

list incompleteness is called coverage bias, or more 

specifically, bias due to under coverage of the list. 

To reduce the amount of this bias, an additional 

adjustment was calculated and applied to the 

nonresponse-adjusted weight for each responding 

farm. This is called the coverage adjustment. The 

coverage adjustment was calculated within the same 

weight-adjustment groups defined above. 

Coverage Adjustment Computation 

Each farm on the 2009 OREPS mail list was a 

respondent to the 2007 Census of Agriculture. The 

weights of all 2007 census respondents were fully 

adjusted for nonresponse and coverage error. 

Coverage adjustment for the 2007 census was made 

possible through the use of survey data that was 

based on a list (or frame) of geographic land 

segments. In theory, every acre of land in the U.S. 

is contained in one of these segments. This implies 

that a survey based on such a frame will have 

complete coverage and represent all farms in the 

U.S. This survey was used to derive estimates of the 

magnitude of the coverage error associated with the 

census mail list. The nonresponse-adjusted weight 

for each 2007 agricultural census respondent 

received a coverage adjustment based on the 

estimated coverage error obtained from the area 

frame survey. This resulted in a fully coverageadjusted weight for each census respondent. 

These weights were pulled forward for every farm 

on the 2009 OREPS mail list. Summing these 

weights across every farm on the list produces an 

estimate of the total number of farms producing onfarm energy in 2007. These estimates account for 

both 2007 census nonresponse and coverage bias. 

Information contained in the census weights is used 

to create a coverage adjustment for the 2009 OREPS. 

This information is somewhat dated (2007 vs. 2009), 

but still useful for accounting for the 2009 OREPS 

list coverage bias 

The coverage-adjustment for responding farms to the 

2009 OREPS was calculated by first summing the 

2007 census fully adjusted weight across all farms 

residing in the weight-adjustment group. This gives 

an estimate of the total number of energy producing 

farms in a state that would fall into that group, 

whether they are contained on the 2009 OREPS mail 

list or not. This number is divided by the sum of the 

nonresponse-adjusted weights for all responding 

farms in the group. This results in the 2009 OREPS 

coverage adjustment for that group. If the sum of the 

fully adjusted census weights in a group for all farms 

in the group is 60 and the sum of the nonresponseadjusted weight across all responding farms in the 

group is 50, the 2009 OREPS coverage-adjustment is 

60/50 or 1.2. Multiplying the coverage adjustment 

by the nonresponse adjusted weight results in the 

fully-adjusted 2009 OREPS weight. In the given 

example with 40 responding farms, this would be 

1.25 x 1.2=1.5. Note that 1.5 x 40=60. This 

represents the estimated total number of energyproducing farms that would fall into that group, 

whether on the list or not. All responding farms in a 

group will have the same fully-adjusted 2009 

OREPS weight. 

Summary Weights 

Many of the fully adjusted weights for the 2009 

OREPS are not whole numbers (integers). Using 

these weights to create the estimates published in the 

tables would result in the tables having lots of 

fractional values. These would be difficult to read or 

could cause consistency problems between different 

tables. To avoid some of these problems, summary 

weights were created by moving the fully adjusted 

weights randomly up or down to the nearest integer 

in an unbiased manner by retaining the weighting 

cell total. This process is called weight 

integerization. The resulting integer summary 

weights are used to actually produce the numbers 

published in the tables. 

Explanation of Published Ratios 

Table 1. Wind Turbines – Calculations for columns 

3, 4, and 5 in Table 1 include only those surveyed 

farms reporting positive data values for both the 

numerator and the denominator. 

Column 3. Average Rated Generating Capacity Per 

Turbine - This is computed as the estimated total 

kilowatts of rated generating capacity, divided by the 

estimated number of actively generating turbines. 
 

2007 CENSUS OF AGRICULTURE APPENDIX A A-5

USDA, National Agricultural Statistics Service 

Column 4. Average Installation Cost Per Turbine -

This is computed as the estimated total system 

installation cost (includes outside funding) for all 

turbines, divided by the estimated number of 

turbines owned and used. 

 

Column 5. Percent of Installation Cost Provided by 

Outside Funding - This is computed as the 

estimated installation cost received from outside 

funding, divided by the estimated total installation 

cost. 

Table 2. Methane Digesters – Calculations for 

columns 3, 4, and 5 in Table 2 include only those 

surveyed farms reporting positive data values for 

both the numerator and denominator. 

Column 3. Average Methane Volume Production 

Per Digester - This is computed as the estimated 

total amount of methane produced, divided by the 

estimated total number of methane digesters. 

Column 4. Average Installation Cost Per Digester - 

This is computed as the estimated total installation 

cost of methane digesters, divided by the estimated 

total number of digesters on farms with positive 

installation costs. 

Column 5. Percent of Installation Cost Provided by 

Outside Funding - This is computed as the 

estimated installation cost provided by outside 

funding, divided by the estimated total installation 

cost. 

Table 3. Solar Panels – Calculations for columns 4, 

5, and 6 in Table 3 include only surveyed farms 

reporting positive data values for both the numerator 

and denominator. 

Column 4. Average Photovoltaic Solar Panel 

Generating Capacity Per Farm - This is computed 

as the estimated total generating capacity of all 

photovoltaic solar panels, divided by the estimated 

total number of farms utilizing photovoltaic solar 

panels. 

Column 5. Average Installation Cost Per Farm -

This is computed as the estimated total solar panel 

system installation cost, divided by the estimated 

number of farms having positive solar panel 

installation cost. 

Column 6. Percent of Installation Cost Provided by 

Outside Funding - This is computed as the 

estimated installation cost received from outside 

funding, divided by the estimated total installation 

cost. 

Table 4. Energy Cost Savings - 

Column 2. Average Dollars Saved on Utility Bills 

Per Farm - This is computed as the estimated total 

amount saved on utility bills for farms having wind 

turbines, solar panels, and/or methane digesters, 

divided by the estimated total number of farms 

having positive utility bill savings. 

MEASURES OF PRECISION AND 

ACCURACY OF THE ESTIMATES

All numbers published in the tables are merely 

estimates of particular characteristics of the entire 

population of energy-producing farms. The true 

values of these characteristics are unknown and 

unknowable. Even though an attempt was made to 

contact every farm on the mail list, the estimates 

produced by the survey will not exactly attain the 

true values. This is due to a number of factors, such 

as survey nonresponse, mail list incompleteness, and 

the weight integerization process. Hypothetically, if 

the entire survey process was repeated over and over 

again, each replication of the survey would almost 

certainly produce a different estimate for the same 

population value every time. This is because each 

time the survey is carried out, a different set of 

respondents would be obtained, response rates would 

fluctuate, and the estimated coverage rates of the 

mail list could change. 

It is possible to obtain an idea of how much this 

variation would be on average by calculating the 

estimate‟s variance. The variance of an estimate 

gives a measure of the average squared random 

fluctuation that would be seen in an estimate if the 

survey was carried out multiple times. This is 

referred to as the precision of the estimate. Because 

the variance measures random fluctuation in squared 

units, the square root of the variance is computed to 
 

A-6 APPENDIX A 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

obtain a random fluctuation measure that is in the 

same units as the original estimate. This is called the 

standard error (se) of the estimate. The standard 

error can then be divided by the estimate itself to 

show the relative size of the standard error to the 

estimate. If this ratio is small, the estimate is quite 

precise. If this ratio is large, the estimate is 

imprecise. An estimate of 100 with a standard error 

of 2 would result in a relative standard error of .02 or 

2 percent. This would be a very precise estimate. 

An estimate of 100 with a standard error of 20 would 

result in a relative standard error of 20 percent. This 

might be considered to be an imprecise estimate. The 

idea of precision can be made a little more clear by 

stating that if the estimate is 100 with a standard 

error of 2, you could be quite confident that the true 

population value would be in the interval 96 to 104 

(within two standard deviations of the estimate). 

Unbiased estimates are generally accurate. This is to 

say that if the survey is hypothetically repeated over 

and over, the average of the estimates obtained 

would be very close to the true value being 

estimated. This does not mean that any particular 

realization of the estimate will be “close” to the true 

value. An accurate estimate that is not precise has a 

good chance of missing the true value of the 

characteristic being estimated by a significant 

amount. 

If the estimate contains some bias, both precision 

and accuracy are measured by computing the mean 

squared error (mse) of the estimate. Bias is 

systematic error that would be about the same for 

every hypothetical replication of the survey. Bias is 

not random fluctuation and affects the accuracy of 

the estimate. The weight adjustments described 

earlier are used to decrease biases in the estimates. 

However, the weight integerization process 

introduces some bias. Ideally, the amount of bias 

contained in an estimate should be small or nonexistent, but in conducting actual surveys, some 

biases may be hard to avoid. Biased estimates can 

be precise, but in hypothetical replications of the 

survey, will tend to be systematically lower or higher 

than the true population value being estimated. 

Highly biased estimates are generally quite 

inaccurate and are not desirable. 

The mean squared error is computed by adding a 

term to the variance called the estimated squared 

bias. The mean squared error can be used to measure 

the combined effects of random variation and bias 

contained in an estimate. Like the variance, the 

mean squared error is measured in squared units, so 

the square root of the mean squared error is often 

taken. This results in what is called the root mean 

squared error (rmse). Like the standard error, the 

ratio of the root mean squared error to the estimated 

value can be created. It is often multiplied by 100 

and expressed as a percent. This ratio gives a 

measure of the relative root mean squared error

(relative rmse) of the estimate. When this ratio is 

small (close to 0 percent), the estimate is both very 

precise and very accurate. A large ratio (20 percent 

or more) might indicate that the estimate is precise 

but not very accurate. Another possibility is that the 

estimate might be accurate but not very precise. A 

third possibility is that the estimate might reflect 

only a moderate level of both accuracy and 

precision. 
 

2007 CENSUS OF AGRICULTURE APPENDIX A A-7

USDA, National Agricultural Statistics Service 

Table A. Reliability Estimates of Operations Reporting Small and Large Wind Turbines: 2009

State

Small wind turbines Large wind turbines

Farms

Average per turbine

Farms

Average per turbine

Rated generating

capacity Installation cost Rated generatingcapacity Installation cost

Number Relative

RMSE kW RelativeRMSE Dollars RelativeRMSE Number RelativeRMSE kW RelativeRMSE Dollars RelativeRMSE

United States ....................

Alabama ...........................

Alaska ...............................

Arizona .............................

Arkansas ..........................

California ..........................

Colorado ...........................

Connecticut ......................

Delaware ..........................

Florida ..............................

Georgia .............................

Hawaii ...............................

Idaho ................................

Illinois ...............................

Indiana ..............................

Iowa ..................................

Kansas .............................

Kentucky ...........................

Louisiana ..........................

Maine ................................

Maryland ...........................

Massachusetts .................

Michigan ...........................

Minnesota .........................

Mississippi ........................

Missouri ............................

Montana ...........................

Nebraska ..........................

Nevada .............................

New Hampshire ................

New Jersey .......................

New Mexico ......................

New York ..........................

North Carolina ..................

North Dakota ....................

Ohio ..................................

Oklahoma .........................

Oregon .............................

Pennsylvania ....................

Rhode Island ....................

South Carolina ..................

South Dakota ....................

Tennessee ........................

Texas ................................

Utah ..................................

Vermont ............................

Virginia .............................

Washington ......................

West Virginia ....................

Wisconsin .........................

Wyoming ..........................

Other States 1...................

1,406

3

8

63

7

134

98

1

-

5

4

43

39

28

49

39

18

1

2

32

2

22

34

99

3

21

63

7

8

11

3

28

58

12

5

44

20

37

26

2

-

11

9

102

31

43

11

50

4

46

20

-

1.4

48.1

11.9

6.9

8.5

5.5

6.9

16.0

-

12.3

12.1

8.7

7.8

9.3

7.4

5.7

16.5

60.1

27.9

7.2

29.5

6.4

10.7

4.8

23.6

11.9

6.2

8.0

34.3

16.0

46.7

14.4

7.6

10.9

35.7

10.6

14.7

7.9

7.0

30.6

-

7.6

23.7

6.9

9.0

4.9

11.0

7.6

19.9

5.4

12.8

-

6

(D)

1

1

2

3

3

(D)

-

1

(D)

1

4

5

2

8

6

(D)

(D)

5

(D)

7

2

20

1

3

3

1

1

3

8

1

5

2

(D)

2

2

1

3

(D)

-

4

(D)

4

1

3

1

19

5

8

2

-

3.4

(D)

11.0

11.0

57.3

4.3

12.5

(D)

-

13.6

(D)

2.8

8.0

11.7

10.2

7.9

11.3

(D)

(D)

9.0

(D)

7.2

11.8

6.1

4.2

38.4

13.4

6.7

7.9

18.5

7.2

5.7

7.4

5.2

(D)

8.4

13.5

4.5

7.7

(D)

-

35.8

(D)

9.4

4.7

2.2

25.5

16.7

14.8

1.2

8.2

-

12,972

(D)

4,394

2,768

5,800

13,955

4,581

(D)

-

5,250

(D)

1,799

12,778

11,448

7,870

23,840

10,084

(D)

(D)

17,353

(D)

43,218

9,981

37,647

4,467

7,779

6,293

1,563

1,455

9,850

47,518

4,807

22,254

12,800

15,778

11,257

4,156

3,209

7,148

(D)

-

19,064

8,177

8,493

2,562

16,847

2,971

12,669

44,400

15,329

4,648

-

1.7

(D)

24.9

16.0

56.9

4.1

4.6

(D)

-

8.4

(D)

5.5

14.1

9.3

9.3

9.3

7.0

(D)

(D)

6.9

(D)

7.9

19.3

4.5

6.6

23.9

5.9

15.4

12.4

14.1

11.9

10.9

9.9

6.8

10.8

11.8

9.9

10.2

20.9

(D)

-

13.1

13.0

4.2

9.8

5.5

34.0

7.9

16.0

1.9

10.4

-

14

-

-

-

-

-

-

-

-

-

-

-

-

-

-

9

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

5

8.4

-

-

-

-

-

-

-

-

-

-

-

-

-

-

6.0

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

20.0

1,035

-

-

-

-

-

-

-

-

-

-

-

-

-

-

1,359

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

453

9.7

-

-

-

-

-

-

-

-

-

-

-

-

-

-

5.8

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

54.0

1,339,143

-

-

-

-

-

-

-

-

-

-

-

-

-

-

1,784,889

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

536,800

8.9

-

-

-

-

-

-

-

-

-

-

-

-

-

-

5.6

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

55.7

1 Other States include Kansas, Minnesota, and Montana.
 

A-8 APPENDIX A 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

Table B. Reliability Estimates of Operations Reporting Methane Digesters and Solar Panels: 2009

State

Methane digesters Solar panels

Farms

Average per methane digester

Farms

Average per farm

Methane produced Installation cost PV rated

generating capacity Installation cost

Number Relative

RMSE

Cubic

feet

Relative

RMSE Dollars RelativeRMSE Number RelativeRMSE Watts RelativeRMSE Dollars RelativeRMSE

United States .............

Alabama .....................

Alaska ........................

Arizona .......................

Arkansas ....................

California ....................

Colorado ....................

Connecticut ................

Delaware ....................

Florida ........................

Georgia ......................

Hawaii ........................

Idaho ..........................

Illinois .........................

Indiana .......................

Iowa ...........................

Kansas .......................

Kentucky ....................

Louisiana ...................

Maine .........................

Maryland ....................

Massachusetts ...........

Michigan ....................

Minnesota ..................

Mississippi .................

Missouri .....................

Montana .....................

Nebraska ...................

Nevada ......................

New Hampshire .........

New Jersey ................

New Mexico ...............

New York ...................

North Carolina ............

North Dakota ..............

Ohio ...........................

Oklahoma ..................

Oregon .......................

Pennsylvania .............

Rhode Island ..............

South Carolina ...........

South Dakota .............

Tennessee .................

Texas .........................

Utah ...........................

Vermont .....................

Virginia .......................

Washington ................

West Virginia ..............

Wisconsin ..................

Wyoming ....................

Other States 1............

121

-

-

-

-

14

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

5

5

-

-

-

-

-

-

-

-

16

-

-

-

-

-

13

-

-

-

-

-

-

8

-

-

-

21

-

39

1.5

-

-

-

-

8.9

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

1.0

1.0

-

-

-

-

-

-

-

-

1.5

-

-

-

-

-

1.0

-

-

-

-

-

-

1.0

-

-

-

2.1

-

4.9

30,515,800

-

-

-

-

29,194,314

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

36,923,333

69,105,120

-

-

-

-

-

-

-

-

18,611,675

-

-

-

-

-

18,951,843

-

-

-

-

-

-

(D)

-

-

-

(D)

-

26,034,140

2.0

-

-

-

-

20.5

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

(Z)

(Z)

-

-

-

-

-

-

-

-

(Z)

-

-

-

-

-

(Z)

-

-

-

-

-

-

(D)

-

-

-

(D)

-

6.0

1,718,562

-

-

-

-

1,794,444

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

1,322,222

3,123,333

-

-

-

-

-

-

-

-

1,611,206

-

-

-

-

-

642,188

-

-

-

-

-

-

1,718,750

-

-

-

1,608,924

-

2,181,189

1.3

-

-

-

-

23.3

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

(Z)

(Z)

-

-

-

-

-

-

-

-

(Z)

-

-

-

-

-

(Z)

-

-

-

-

-

-

(Z)

-

-

-

1.8

-

5.6

7,968

33

16

255

41

1,906

504

26

4

88

32

520

131

58

127

40

116

67

13

97

21

63

75

73

23

93

238

65

51

49

138

258

156

104

29

130

187

332

173

12

20

55

66

573

133

110

83

205

27

176

176

-

1.5

7.7

8.0

4.9

6.6

5.4

5.1

12.1

17.1

6.3

6.8

6.0

6.1

8.2

6.3

6.7

4.1

9.6

10.3

5.9

11.2

5.9

6.5

6.6

13.3

6.1

4.3

4.3

12.6

8.4

5.5

4.2

6.2

8.1

9.9

6.5

5.2

5.3

5.6

7.9

10.4

3.3

6.5

4.3

5.3

6.2

5.7

5.6

9.9

6.0

5.6

-

4,449

865

865

2,002

833

11,229

1,654

4,173

15,500

2,162

3,625

1,790

916

4,575

543

1,988

408

776

876

1,680

2,665

3,678

841

1,409

706

1,022

988

742

1,832

1,641

14,081

1,261

2,501

1,015

429

1,614

428

3,002

1,750

(D)

(D)

696

1,065

783

1,211

1,304

869

1,547

521

2,484

1,275

-

3.8

23.3

7.9

4.9

14.6

5.6

4.5

16.4

19.3

6.6

9.3

3.5

3.5

19.1

5.7

13.8

11.4

5.9

11.7

6.0

26.8

6.5

9.2

7.4

13.4

12.7

3.0

6.6

13.7

5.6

4.4

4.2

4.8

8.1

6.1

10.7

22.9

8.0

4.8

(D)

(D)

3.9

8.7

2.4

4.2

1.2

10.1

2.7

9.2

13.8

5.1

-

31,947

6,948

9,134

19,992

7,502

78,910

16,879

29,571

101,250

12,223

28,545

16,665

12,524

39,018

5,262

17,791

4,607

6,305

10,970

13,892

24,201

27,624

7,416

11,178

11,593

9,429

9,180

5,632

21,971

16,173

112,855

12,888

21,661

10,198

5,048

12,122

4,612

22,147

20,699

30,960

5,047

7,470

8,657

7,692

14,573

15,510

12,868

10,377

8,166

17,607

10,362

-

2.8

12.3

9.0

2.7

8.0

4.5

2.7

17.6

18.7

4.0

8.3

3.2

6.9

16.6

6.4

18.6

5.4

7.5

10.1

7.2

15.0

2.4

6.7

5.2

11.2

13.2

3.2

4.8

8.2

4.7

4.4

4.6

4.3

3.5

10.6

16.2

9.7

6.9

2.8

28.3

6.9

2.7

13.4

1.9

5.7

1.7

5.4

2.6

7.4

8.2

2.7

-

1 Other States include Colorado, Connecticut, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Maryland, Mississippi, Missouri, Montana, Nebraska, North 

Carolina, Ohio, Oklahoma, Oregon, South Dakota, Tennessee, Texas, Washington, and Wyoming.
 

2007 CENSUS OF AGRICULTURE APPENDIX B B-1

USDA, National Agricultural Statistics Service 

Appendix B.

General Explanation and Report Form

DEVELOPMENT OF THE REPORT FORM 

The 2009 On-Farm Renewable Energy Production 

Survey report form was developed through input 

from other government agencies, special interest 

groups and each of NASS‟s field offices. Report 

form testing was conducted in several States and 

included various types of producers. Producers were 

asked to evaluate the report form through cognitive 

interviews. 

TERMS AND DEFINITIONS 

The following definitions and explanations provide a 

detailed description of specific items and terms used 

in this publication and on the report form. Copies of 

the 2009 On-Farm Renewable Energy Production 

Survey report form and instruction sheet are included 

in this appendix. 

Biodiesel. A non-petroleum based diesel fuel 

consisting of long-chain alkyl esters. Biodiesel is 

typically made by chemically-reacting lipids (e.g., 

vegetable oil) and alcohol. It can be used (alone or 

blended with conventional petrodiesel) in 

unmodified diesel-engine vehicles. 

Energy Audit. An audit conducted by a certified 

energy manager or professional engineer that focuses 

on potential capital-intensive projects and involves 

detailed gathering of field data and engineering 

analysis. The audit will provide detailed project costs 

and savings information with a high level of 

confidence sufficient for major capital investment 

decisions. 

Ethanol. A fuel produced by converting crops such 

as corn, sugarcane, or wood into alcohol sugar 

(CH3CH2OH). This may then be blended with 

gasoline to enhance octane, reduce exhaust pollution, 

and reduce reliance on petroleum fuels. 

Generating Capacity. The ability to generate 

electricity is measured in watts. Wind turbines 

currently manufactured have power ratings ranging 

from 250 watts to 5 megawatts (MW). A 10-kW 

wind turbine can generate about 10,000 kWh 

annually at a site with wind speeds averaging 

12 miles per hour, or about enough to power a 

typical household. A 5-MW turbine can produce 

more than 15 million kWh in a year - enough to 

power more than 1,400 households. The average 

U.S. household consumes about 10,000 kWh of 

electricity each year. 

Geothermal Energy. Energy, in the form of heat, 

stored in the earth, which originates from the original 

formation of the planet, from radioactive decay of 

minerals, and from solar energy absorbed at the 

surface. 

The “Grid”. The grid consists of two 

infrastructures: the high-voltage transmission 

systems, which carry electricity from the power 

plants and transmit it hundreds of miles away, and 

the lower-voltage distribution systems, which draw 

electricity from the transmission lines and distribute 

it to individual customers. 

Hydroelectric Energy. Power produced through 

use of the gravitational force of falling or flowing 

water 

Kilowatt. kW = 1,000 watts, megawatt (MW) = 1 

million watts, and gigawatt (GW) = 1 billion watts. 

Kilowatt Hour. One kilowatt (1,000 watts) of 

electricity produced or consumed for one hour. For 

example, one 50-watt light bulb left on for 20 hours 

consumes one kilowatt-hour of electricity (50 watts x 

20 hours = 1,000 watt-hours = 1 kilowatt-hour). 
 

B-2 APPENDIX B 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 

Manure/Methane Digester. Anaerobic digestion 

involves the decomposition of manure and 

processing of by-products and other materials into 

effluent and biogas. Microorganisms perform the 

decomposition process in an anaerobic digester, 

which can be designed in several ways. Once biogas 

is harvested from the processed manure, it can be run 

through an engine to generate electricity, used in 

place of natural gas, or flared. 

Methane. A chemical compound with the molecular 

formula CH4. It is the simplest alkane, and the 

principal component of natural gas. 

Outside Funding Sources. Federal, state, and local 

governments, universities, and private industries 

provide funds for renewable energy installation 

costs. 

Solar Energy. Energy, in the form of heat, 

generated by the sun. 

Solar Panel, Photovoltaic. Solar photovoltaic 

modules use solar cells to convert light from the sun 

into electricity. 

Solar Panel, Thermal. Flat plate and evacuated 

tube solar collectors are typically used to collect heat 

for space heating or domestic hot water. 

Wind Power. Winds are caused by the uneven 

heating of the atmosphere by the sun, the 

irregularities of the earth's surface, and rotation of 

the earth. Wind flow patterns are modified by the 

earth's terrain, bodies of water, and vegetative cover. 

This wind flow, or motion energy, when "harvested" 

by modern wind turbines, can be used to generate 

electricity. The terms "wind energy" or "wind 

power" describe the process by which the wind is 

used to generate mechanical power or electricity. 

The power available in the wind is proportional to 

the cube of its speed, which means that doubling the 

wind speed increases the available power by a factor 

of eight. A turbine operating at a site with an average 

wind speed of 12 mph could in theory generate about 

33 percent more electricity than one at an 11-mph 

site, because the cube of 12 (1,768) is 33 percent 

larger than the cube of 11 (1,331). 

Wind Powered Device. Usually wind turbines, but 

can also be windmills. If the energy created is used 

directly by machinery, such as a pump or grinding 

stones, the machine is a windmill. If the energy is 

converted to electricity, the machine is called a wind 

generator, wind turbine, wind power unit (WPU), 

wind energy converter (WEC), or aero generator. 

Wind turbines convert wind energy to electricity. 
 

2007 CENSUS OF AGRICULTURE APPENDIX B B-3

USDA, National Agricultural Statistics Service 
 

B-4 APPENDIX B 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 
 

2007 CENSUS OF AGRICULTURE APPENDIX B B-5

USDA, National Agricultural Statistics Service 
 

B-6 APPENDIX B 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 
 

2007 CENSUS OF AGRICULTURE APPENDIX B B-7

USDA, National Agricultural Statistics Service 
 

B-8 APPENDIX B 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service 
 

2007 CENSUS OF AGRICULTURE APPENDIX B B-9

USDA, National Agricultural Statistics Service 
 

B-10 APPENDIX B 2007 CENSUS OF AGRICULTURE 

USDA, National Agricultural Statistics Service