1

MEMORANDUM 

TO: Jim Eddinger, U.S. Environmental Protection Agency, OAQPS/SPPD 

FROM: Amanda Singleton and Graham Gibson, ERG 

DATE: April 2010 

SUBJECT: New Unit Analysis for the Industrial, Commercial, and Institutional Boilers 

National Emission Standards for Hazardous Air Pollutants – Area Source 

1.0 INTRODUCTION 

This memorandum describes the estimation of new area source boilers projected to be 

built by 2013 from the baseline year of 2004. The results of this analysis are used to estimate 

costs and impacts for new sources for a national emission standard for hazardous air pollutants 

(NESHAP) for industrial/commercial/institutional boilers. The year 2013 was selected because 

it is five years from the expected proposal and promulgation dates of the boiler NESHAP. The 

methods used for this are similar to the methods used to project new major source boilers.1

This memorandum is separated into the following sections: 

1.0 Introduction 

2.0 Data Sources 

3.0 Methodology for Estimating New Units 

4.0 Results 

5.0 References 

Appendix A – Distribution of Model Boilers between Industrial and Commercial Sectors 

Appendix B – EIA Fuel Consumption 

Appendix C – Boiler Inspector Data: Boiler Installation Dates 

Appendix D – Distribution of New Units to Affected Sectors 
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2.0 DATA SOURCES

The number of existing area source boilers categorized into model boilers according to 

fuel type and boiler size.2 A 13-state boiler inspector inventory that was compiled in 2005 and 

2006 was used to estimate the number of existing model boilers nationwide3. These data served 

as the baseline for estimating new units expected to be installed. The inspector inventory also 

included boiler installation dates. The energy consumption forecasts were provided by the 

Energy Information Administration (EIA) of the U.S. Department of Energy4. The data 

forecasted energy consumption according to fuel type. 

3.0 METHODOLOGY FOR ESTIMATING NEW UNITS 

3.1 Distillate Liquid Units 

Similar to the projections made for major source boilers, the estimated number of new 

distillate liquid fuel boilers was estimated using fuel consumption data from the Energy 

Information Administration (EIA). The expected percent difference in fuel consumption was 

calculated for petroleum between 2004 and 2013. Appendix B shows the details of the EIA data. 

Table 3-1. Expected Fuel Consumption Differences by Sector4

Fuel Consumption (Quadrillion Btu per year) Percent Difference 

from 2004 

Fuel 2004 2013 2013 

Petroleum 40.13 44.80 11.6% 

Source: U.S. Department of Energy. Energy Information Administration. Annual Energy Outlook 2006 with 

Projections to 2030. Figure 3. Energy Consumption by Fuel, 1980-2030 (quadrillion Btu). 

Next, the projected fuel consumption was divided by the average capacity of the model 

boiler in each size range in order to estimate the total number of projected units. Finally, in 

order to get an estimate of the new units, the existing number of distillate oil fired boilers was 

subtracted from the total projected number of units in each target year. A summary of the results 

of this boiler forecast analysis is shown in Table 3-1. 

The methodology involved in estimating new liquid-fired area source boilers is identical 

to the method used in the major source analysis1

. No new boilers were projected burning 

gaseous fuels because they are not subject to the NESHAP and would have no effect on 
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regulatory impacts analyses. The EIA fuel consumption projections for liquid fuels, along with 

calculated percent differences for 2013, are given in Table 3-1. 

3.2 Coal, Wood, and Residual Liquid Units 

There are only a small amount of solid fuel and residual oil fired-boilers with installation 

data in the boiler inspector database. This installation data does not provide any indication of an 

upward trend in installation of boilers with these fuel types over recent years. As a result, the 

fuel consumption estimates and trends from the EIA were not deemed to be the most appropriate 

predictors of new solid fuel or residual oil fired boilers. Using engineering judgment, units 

burning these three fuel types were calculated based on the annual average number of units 

installed over a recent 10-year period. A summary of the installation dates of boilers in the 

boiler inspector dataset based on fuel type, and size category is presented in Table 3-2. Details 

of the installation dates are shown in Appendix C. 

Table 3-2 Distribution of Installation Dates in the Boiler Inspector Dataset 

Fuel 

Category 

Size 

Category 

No 

Installation 

Year 

Information 

Percentage 

of Units 

with 

Installation 

Data 

1900 

to 

1950 

1951 

to 

1960 

1961 

to 

1970 

1971 

to 

1980 

1981 

to 

1990 

1991 

to 

2002 

Post 

2002* 

Residual Oil 234 54.91% 34 72 75 27 44 21 12 

Wood/ 

Biomass 473 41.68% 121 30 16 35 91 43 2 

Coal 281 46.48% 61 26 20 40 51 40 6 

Total 

< 10 

mmBtu/hr 

180,741 4,439 10,717 21,401 22,790 46,753 94,854 12,509 

Residual Oil 7 65.00% 0 3 4 0 2 3 1 

Wood/ 

Biomass 26 84.24% 22 8 20 23 39 23 4 

Coal 14 60.00% 4 9 2 2 4 0 0 

Total 

≥ 10 

mmBtu/hr 

2,682 141 354 1,164 1,107 964 1,895 208 

 

*Boilers installed between 2003 and 2006 listed in the boiler inspector database were not included in the forecasting analysis 

because the total number of annual installations was not deemed to be a complete dataset of units installed in the states 

during these years. 
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Since the data collection activities for the area source boiler standard were conducted 

between 2004 and 2006, the boiler inspector dataset was deemed to be incomplete for certain 

states starting with the year 2003. Therefore, the time frame selected for the basis of calculating 

the average annual number of installations was the most recent 10-year period between 1993 and 

2002. 

As shown in Table 3-2, some of the units in the boiler inspector dataset did not provide 

data on the year the boiler was installed. In order to adjust for this data gap, the average number 

of annual installations for each fuel type and size category was adjusted to reflect the distribution 

of units without an installation date. The adjusted value represents an estimate of the annual 

number of units installed for each fuel and size category in the thirteen states which are 

contained in the boiler inspector dataset. Equations 1 and 2 were used to distribute the units with 

unknown installation dates. 

%Installation = 100 * ( Σ Ni ) / N2008 Equation 1 

Where: 

%Installation = Percentage of units expected to not have a known installation date 

Σ Ni = Sum of number of boilers with a known installation date between 1900 and 2006 

N2008 = Number of boilers in operation in 2008. 

This percentage was then applied to the average number of boiler installations between 

1993 and 2002 in order to account for any boilers with unknown installation dates. An average 

number of installations per year was calculated for the 10-year period between 1993 and 2002 

using Equation 2. 

Navg = Xavg / ( %Installation / 100 ) Equation 2 

Where: 

Navg = Average number of all known boilers installations between 1993 and 2002 

Xavg = Average number of known boiler installations between 1993 and 2002 

%Installation = Percentage of units expected to not have a known installation date 
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Since this boiler inspector data was representative of only 13 states, the average annual 

number of boiler installations was extrapolated to be representative of all 50 states. This was 

done by multiplying the average number of known boiler installations by a ratio of 50 over 13. 

Since this average was generated for a recent 10-year period, it was assumed to be a constant 

predictor of the annual number of new boiler installations for the next 10-year period. The 

results of this forecast analysis indicate that approximately 31 new coal, 40 new wood, and 28 

new residual oil fired units will be installed each year. 

Next, the number of projected new boilers in a target year (2013) was calculated using 

Equation 3. 

NTY = Xextrapolated * (TY – 2008) Equation 3 

Where: 

NTY = Number of new boiler installations in the target year (2013) 

Xextrapolated = Average number of boiler installations per year, nationwide 

TY = Target year (2013) 

Based on the data available, no growth trend in the number of installed coal, wood, and 

residual-oil fired units was identified over the last 10-year period. As a result, the projected 

number of annual installations is estimated to stay constant between 2004, the base year of this 

forecast analysis, and 2013. 

Table 2-2 Forecasted Solid Fuel and Residual Oil Fired Units 

Fuel 

Size 

Category 

Average 

Annual 

Number of 

New Boiler 

Installations 

Projected 

Number 

of New 

Units by 

2013 

< 10 

mmBtu/hr 19 95 

Residual 

Oil 

≥ 10 

mmBtu/hr 9 45 

< 10 

mmBtu/hr 28 140 

Wood/ 

Biomass 

≥ 10 

mmBtu/hr 12 60 

< 10 

mmBtu/hr 31 155 

Coal 

≥ 10 

mmBtu/hr 0* 0 

*No coal units at area source facilities ≥ 10 mmBtu per hour are listed in the boiler inspector database with an installation date 

since 1989. Additionally several Pennsylvania school board officials cited regional air pollution control regulations, increasing 

insurance costs, and maintenance issues as other reasons why there has not been a trend to replace old coal units with newer coal 

units. These officials noted that the units have switched to gas-fired units in recent years. Based on the average number of units 

installed each year over the last 10 year period, and other factors which have limited the number of new coal units in recent 

years, no new coal units at area source facilities ≥ 10 mmBtu/hr are predicted to come online by 2013. 
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3.3 Assigning Affected Sectors to New Units 

After the 2013 projections were estimated for each fuel category, the units were 

distributed according to affected sector, either commercial or industrial. In order to distribute the 

projected models to a sector, the SIC distribution of existing area source boilers was multiplied 

by the total number of projected units assigned to each new model boiler. The distribution of SIC 

codes and the resulting new model units assigned to each sector is shown in Appendix D. 

4.0 RESULTS

The results of the new boiler analysis by model and year for the industrial and 

commercial sectors are presented in Appendices A-1 and A-2, respectively. The combined total 

number of new boilers for 2013 is expected to be 6,779. The majority of all new boilers are 

expected to be liquid-fired boilers in the commercial sector. 

5.0 REFERENCES

1. Gibson, G., ERG. New Unit Analysis for Industrial, Commercial, and Institutional 

Boilers and Process Heaters National Emission Standards for Hazardous Air Pollutants – 

Major Source. April, 2010. 

2. Singleton, A. ERG. Methodology for Developing Model Units for Industrial, 

Commercial, and Institutional Boilers National Emission Standards for Hazardous Air 

Pollutants – Area Source. April 2010. 

3. Thirteen-state Boiler Inspector Inventory. Data compiled 2005-2006. For a description of 

the dataset see April 2010 Memorandum: Development of Model Units for Area Source 

Boilers. ERG, April 2010. 

4. U.S. Department of Energy. Energy Information Administration. Annual Energy Outlook 

2006 (Early Release) with Projections to 2030. Figure 3. Energy Consumption by Fuel, 

 1980-2030 (quadrillion Btu). 
Appendix A: EIA Fuel Consumption Data

Annual Energy Outlook 2006 (Early Release)

Release Date: December 12, 2005

Next Release Date: December 2006

(Full report available early 2006)

Figure 3. Energy Consumption by Fuel, 1980-2030 (quadrillion Btu)

 Petroleum Natural Gas Coal Nuclear Hydropower Renewable/Other(excl. Hydro.)

1980 34.20236 20.3941 15.38779 2.739169 2.900144 2.594276

31.93104 19.92776 15.89158 3.007589 2.757968 2.712606

30.23161 18.50509 15.29993 3.131148 3.265558 2.719794

30.05392 17.35679 15.87882 3.202549 3.52726 2.960638

31.05133 18.50699 17.05914 3.552531 3.385811 3.044835

30.92215 17.83393 17.46494 4.075563 2.970192 3.062536

32.19608 16.70793 17.24367 4.380109 3.071179 3.060363

32.86505 17.74434 18.01708 4.753933 2.634508 3.052424

34.22199 18.55244 18.88587 5.586968 2.334265 3.154384

34.21111 19.71169 19.10017 5.602161 2.837263 3.456946

33.55253 19.72959 19.17742 6.10435 3.046391 3.086181

32.84536 20.14893 19.00137 6.422132 3.015943 3.142144

33.52659 20.83508 19.15709 6.479206 2.617436 3.289711

33.84148 21.35117 19.86225 6.410499 2.891613 3.264345

34.67027 21.84202 19.96779 6.693877 2.683457 3.381322

1995 34.55347 22.78427 20.14979 7.075436 3.205307 3.463953

35.75685 23.19692 21.02473 7.086674 3.589656 3.547143

36.26565 23.32851 21.49186 6.596992 3.640458 3.434695

36.93354 22.93558 21.72283 7.067809 3.297054 3.263578

37.95965 23.01009 21.68023 7.610256 3.267575 3.331056

38.40362 23.91645 22.64488 7.862349 2.811116 3.347116

38.33315 22.90578 21.94353 8.032697 2.241858 3.086492

38.40135 23.6282 21.96475 8.143089 2.689017 3.146319

39.0473 23.06872 22.37145 7.958858 2.824533 3.257195

2004 40.13009 22.99105 22.52786 8.231732 2.725219 3.391071

2005 40.22358 22.86413 23.36663 8.080544 2.684348 3.199024

2006 40.37086 22.82558 23.44147 8.219225 2.9446 3.411935

2007 41.31838 23.04497 23.83594 8.409397 3.02649 3.681045

2008 41.8396 23.54848 24.28613 8.422953 3.026717 3.746748

2009 42.43158 23.73113 24.82422 8.438003 3.026791 3.837737

2010 43.14035 24.04343 25.08521 8.441965 3.026791 4.053943

2011 43.77956 24.54411 25.19279 8.453347 3.026791 4.083359

2012 44.33028 25.14415 25.52124 8.463369 3.026791 4.102375

2013 44.79918 25.65771 25.541 8.466047 3.026789 4.187376

2014 45.28099 26.06837 25.59385 8.54078 3.029312 4.282938

2015 45.68502 26.66649 25.66214 8.658575 3.029312 4.397181

46.18589 27.08545 25.89554 8.795967 3.029313 4.519976

46.70186 27.25442 26.23202 8.944653 3.029313 4.610708

47.23509 27.43787 26.64282 9.038681 3.029313 4.699439

47.72386 27.63786 27.01812 9.085279 3.029313 4.817065

48.14332 27.70358 27.64628 9.089217 3.038146 4.964722

48.58918 27.72145 28.24059 9.089217 3.038146 5.073628

49.03895 27.71264 28.91274 9.089217 3.038146 5.210188

49.46225 27.7791 29.54434 9.089217 3.038146 5.323104

50.04314 27.78877 30.26782 9.089217 3.038147 5.476065

50.57268 27.77851 30.88905 9.089217 3.038146 5.569607

51.17701 27.78358 31.57012 9.089217 3.038145 5.703391

51.81902 27.70945 32.33249 9.089217 3.038146 5.782818

52.42754 27.63842 33.14792 9.089216 3.038145 5.868527

53.01973 27.5401 33.92978 9.089216 3.038145 5.911229

2030 53.5784 27.65664 34.48717 9.0881 3.038145 5.985361
Appendix B-1: Calculation of Projected Number of New Industrial Boilers in 2013

Annual Energy 

Consumption 

(MMBtu/yr)

Percentage of 

Boilers with 

Known 

Installation 

Date

Projected Annual 

Energy 

Consumption 

(MMBtu/yr)

Estimate

Number of 

Units

New Biomass Unit 2 Industrial Biomass 3,746 8,760 7.4 0.65 <= 10 41.7% 

New Biomass Unit 3 Industrial Biomass 2,806 8,760 131.0 0.65 > 10 84.2% 

New Coal Unit 2 Industrial Coal 1,882 8,760 6.7 0.65 <= 10 46.5% 

New Distillate Unit 2 Industrial Liquid 10,926 8,760 6.8 0.5 <= 10 3.24E+08 3.61E+08 407

New Distillate Unit 4 Industrial Liquid 1,863 8,760 25.3 0.5 > 10 2.07E+08 2.31E+08 90

Total 5.30E+08 57.5% 5.92E+08 497 

Design Capacity 

Size Category 

Model Identifier Sector Capacity Factor (mmBtu/hr)

Standard Fuel 

Category

Average 

Annual 

Operation 

Hours

Total Number of New Are

Number of 

Boilers in 

2008

2008 

2013 - Fuel Consumptio

Projections

Average Design 

Capacity 

(mmBtu/hr)
Appendix B-2: Calculation of Projected Number of New Commercial Boilers in 2013

Annual Energy 

Consumption 

(MMBtu/yr)

Percentage of 

Boilers with 

Known 

Installation 

Date

Projected Annual 

Energy 

Consumption 

(MMBtu/yr)

Estimate

Number of 

Units

New Biomass Unit 1 Commercial Biomass 3,746 8,760 7.4 0.65 <= 10 41.7% New Biomass Unit 4 Commercial Biomass 660 8,760 21.0 0.65 > 10 84.2% 

New Coal Unit 1 Commercial Coal 1,255 8,760 6.7 0.65 <= 10 46.5% 

New Distillate Unit 1 Commercial Liquid 145,787 8,760 6.8 0.5 <= 10 4.32E+09 4.82E+09 5,435New Distillate Unit 3 Commercial Liquid 7,290 8,760 25.3 0.5 > 10 8.08E+08 9.02E+08 352

New Residual Unit 1 Commercial Liquid 2,061 8,760 5.9 0.5 <= 10 5.37E+07 6.00E+07 95

New Residual Unit 2 Commercial Liquid 76 8,760 17.6 0.5 > 10 5.85E+06 6.53E+06 45

Total 5.18E+09 57.5% 5.79E+09 5,927 

Total Number of New Are

Number of 

Boilers in 

2008

2008 

2013 - Fuel Consumptio

Projections

Average Design 

Capacity 

(mmBtu/hr)

Design Capacity 

Size Category 

Model Identifier Sector Capacity Factor (mmBtu/hr)

Standard Fuel 

Category

Average 

Annual 

Operation 

Hours
Appendix C: Boiler Installation Dates from 13-State Boiler Inspector Inventory

Table 1: Units < 10 mmBtu/hr

Fuel Category

No Installation 

Year Information 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

% units with 

Installed Dates

Total Units in 

Category

Average An

Installatio

(1993 to 20

Gas 172,263 5594 6459 6532 7320 7668 8824 8568 8755 8385 7690 6395 4633 970 51.5% 355,065Distillate Liquid 7,490 618 699 604 701 825 853 777 796 633 516 320 160 9 79.9% 37,284Residual Liquid 234 1 4 1 2 4 3 4 12 54.9% 519 2.71 Biomass 473 434123253311 41.7% 811 3.00 Coal 281 3131143867321 46.5% 525 3.70 Grand Total 180,741 6219 7163 7147 8024 8498 9684 9350 9568 9030 8220 6731 4796 980Table 2: Units ≥ 10 mmBtu/hr

FuelCategory

No Installation 

Year Information 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

% units with 

Installed Dates

Total Units in 

Category

Average An

Installatio

(1993 to 20

Gas 2,434 102 120 118 165 146 146 152 161 161 157 91 71 22 65.8% 7,117Distillate Liquid 201 20 18 11 19 12 30 11 18 13 15 12 4 3 82.9% 1,178Residual Liquid 7 1 2 1 65.0% 20 1.50 Biomass 26 423271 11 121 84.2% 165 2.63 Coal 14 60.0% 35 - Grand Total 2,682 126 140 132 186 165 178 163 180 175 174 105 77 26

Table 3: Summary of Projected New Units

Fuel Size Category

< 10 mmBtu/hr>= 10 mmBtu/hr< 10 mmBtu/hr>= 10 mmBtu/hr< 10 mmBtu/hr>= 10 mmBtu/hr

Notes:

The percent of units with installation dates include other boilers that were installed prior to 1993. Since the data collection activities for the area source boiler standard were cthe boiler inspector dataset was deemed to be incomplete for certain states starting with the year 2003. Therefore, the time frame selected for the basis of calculating the averwas the most recent 10-year period between 1993 and 2002.

Residual LiquidBiomassCoal

3112

0 0

155

60

Average Annual 

Number of 

Installations

19

9

28 140

4595

Projected Number of 

Units in 2013
Appendix D: Sector Distribution of Existing Boilers

FuelCategory

Boiler Capacity 

Range Sector* Number of Boilers Percent

Total Number 

of Boilers

Percentage of Fuel and 

Capacity in Sector

less 10 mmBtu/hr Commercial/Institional 880 0.93023 894 93%

Industrial 66 0.06977 67 7%

≥10 mmBtu/hr Commercial/Institional 130 0.79755 137 80%

Industrial 33 0.20245 35 20%

less 10 mmBtu/hr Commercial/Institional 23 1.00000 23 100%

≥10 mmBtu/hr Commercial/Institional 3 1.00000 3 100%

less 10 mmBtu/hr Commercial/Institional 9 0.50000 15 50%

Industrial 9 0.50000 15 50%

≥10 mmBtu/hr Commercial/Institional 4 4 19%

Industrial 17 17 81%

less 10 mmBtu/hr Commercial/Institional 1 0.33333 2 40%

Industrial 2 0.66667 3 60%

≥10 mmBtu/hr Commercial/Institional 4 1.00000 4 100%

2013 Area Source Model Boilers - NEW UNITS Number of Boilers Design Capacity Boiler Size Category Sector

New Biomass Unit 1 70 7.45 <= 10 Commercial

New Biomass Unit 2 70 7.45 <= 10 Industrial

New Biomass Unit 4 11 21.04 > 10 Commercial

New Biomass Unit 3 49 131.00 > 10 Industrial

New Coal Unit 1 62 6.68 <= 10 Commercial

New Coal Unit 2 93 6.68 <= 10 Industrial

New Distillate Unit 1 5,435 6.76 <= 10 Commercial

New Distillate Unit 2 407 6.76 <= 10 Industrial

New Distillate Unit 3 352 25.31 > 10 Commercial

New Distillate Unit 4 90 25.31 > 10 Industrial

New Residual Unit 1 95 5.95 <= 10 Commercial

New Residual Unit 2 45 17.56 > 10 Commercial

Distillate Liquids

*Distribution of new boilers in industrial or commercial sectors were expected to be similar to the distribution of existing boilers.

* SIC 0 to 39 are considered Industrial and 40 to 99 considered Commercial/Insitutional; Unknown SIC codes were divided up according to the distribution of the sectors for 

known SIC codes. The sector distributions were based on units from Nebraska, India

Coal

Wood/ Biomass

Residual Liquids