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Subpart AA—Pulp and Paper Manufacturing

§ 98.270 Definition of source category.

(a) The pulp and paper manufacturing source category 

consists of facilities that produce market pulp (i.e., standalone pulp facilities), manufacture pulp and paper (i.e., 

integrated facilities), produce paper products from purchased 

pulp, produce secondary fiber from recycled paper, convert paper 

into paperboard products (e.g., containers), or operate coating 

and laminating processes.

(b) The emission units for which GHG emissions must be 

reported are listed in paragraphs (b)(1) through (b)(5) of this 

section:

(1) Chemical recovery furnaces at kraft and soda mills 

(including recovery furnaces that burn spent pulping liquor 

produced by both the kraft and semichemical process).

(2) Chemical recovery combustion units at sulfite 

facilities.

(3) Chemical recovery combustion units at stand-alone 

semichemical facilities.

(4) Pulp mill lime kilns at kraft and soda facilities.

(5) Systems for adding makeup chemicals (CaCO3, Na2CO3) in 

the chemical recovery areas of chemical pulp mills.

§ 98.271 Reporting threshold.
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You must report GHG emissions under this subpart if your 

facility contains a pulp and paper manufacturing process and the 

facility meets the requirements of either §98.2(a)(1) or (a)(2).

§ 98.272 GHGs to report.

You must report the emissions listed in paragraphs (a) 

through (f) of this section:

(a) CO2, biogenic CO2, CH4, and N2O emissions from each kraft 

or soda chemical recovery furnace.

(b) CO2, biogenic CO2, CH4, and N2O emissions from each 

sulfite chemical recovery combustion unit.

(c) CO2, biogenic CO2, CH4, and N2O emissions from each 

stand-alone semichemical chemical recovery combustion unit.

(d) CO2, biogenic CO2, CH4, and N2O emissions from each kraft 

or soda pulp mill lime kiln.

(e) CO2 emissions from addition of makeup chemicals (CaCO3, 

Na2CO3) in the chemical recovery areas of chemical pulp mills.

(f) CO2, CH4,andN2O combustion emissions from each 

stationary combustion unit. You must calculate and report these 

emissions under subpart C of this part (General Stationary Fuel 

Combustion Sources) by following the requirements of subpart C.

§ 98.273 Calculating GHG emissions.

(a) For each chemical recovery furnace located at a kraft 

or soda facility, you must determine CO2, biogenic CO2, CH4, and 

N2O emissions using the procedures in paragraphs (a)(1) through 
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(a)(3) of this section. CH4 and N2O emissions must be calculated 

as the sum of emissions from combustion of fossil fuels and 

combustion of biomass in spent liquor solids.

(1) Calculate fossil fuel-based CO2 emissions from direct 

measurement of fossil fuels consumed and default emissions 

factors according to the Tier 1 methodology for stationary 

combustion sources in §98.33(a)(1). A higher tier from §98.33(a) 

may be used to calculate fossil fuel-based CO2 emissions if the 

respective monitoring and QA/QC requirements described in §98.34 

are met.

(2) Calculate fossil fuel-based CH4 and N2O emissions from 

direct measurement of fossil fuels consumed, default or sitespecific HHV, and default emissions factors and convert to 

metric tons of CO2 equivalent according to the methodology for 

stationary combustion sources in §98.33(c).

(3) Calculate biogenic CO2 emissions and emissions of CH4

and N2O from biomass using measured quantities of spent liquor 

solids fired, site-specific HHV, and default emissions factors, 

according to Equation AA–1 of this section:

Where:

CO2, CH4, or N2O, from Biomass = Biogenic CO2 emissions or 

emissions of CH4 or N2O from spent liquor solids combustion 

(metric tons per year).
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Solids = Mass of spent liquor solids combusted (short 

tons per year) determined according to 

§98.274(b).

HHV = Annual high heat value of the spent liquor 

solids (mmBtu per kilogram) determined 

according to §98.274(b).

(EF) = Default emission factor for CO2, CH4, or N2O, 

from Table AA–1 of this subpart (kg CO2, CH4,

or N2O per mmBtu).

0.90718 = Conversion factor from short tons to metric 

tons.

(b) For each chemical recovery combustion unit located at a 

sulfite or stand-alone semichemical facility, you must determine 

CO2, CH4, and N2O emissions using the procedures in paragraphs 

(b)(1) through (b)(4) of this section:

(1) Calculate fossil CO2 emissions from fossil fuels from 

direct measurement of fossil fuels consumed and default 

emissions factors according to the Tier 1 Calculation 

Methodology for stationary combustion sources in §98.33(a)(1). A

higher tier from §98.33(a) may be used to calculate fossil fuelbased CO2 emissions if the respective monitoring and QA/QC 

requirements described in §98.34 are met.

(2) Calculate CH4 and N2O emissions from fossil fuels from 

direct measurement of fossil fuels consumed, default or sitespecific HHV, and default emissions factors and convert to 

metric tons of CO2 equivalent according to the methodology for 

stationary combustion sources in §98.33(c).
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(3) Calculate biogenic CO2 emissions using measured 

quantities of spent liquor solids fired and the carbon content 

of the spent liquor solids, according to Equation AA–2 of this 

section:

Where:

Biogenic CO2 = Annual CO2 mass emissions for spent liquor 

solids combustion (metric tons per year).

Solids = Mass of the spent liquor solids combusted 

(short tons per year) determined according to 

§98.274(b).

CC = Annual carbon content of the spent liquor 

solids, determined according to §98.274(b) 

(percent by weight, expressed as a decimal 

fraction, e.g., 95% = 0.95).

44/12 = Ratio of molecular weights, CO2 to carbon.

0.90718 = Conversion from short tons to metric tons.

(4) Calculate CH4 and N2O emissions from biomass using 

Equation AA–1 of this section and the default CH4 and N2O 

emissions factors for kraft facilities in Table AA–1 of this 

subpart and convert the CH4 or N2O emissions to metric tons of 

CO2 equivalent by multiplying each annual CH4 and N2O emissions 

total by the appropriate global warming potential (GWP) factor 

from Table A–1 of subpart A of this part.

(c) For each pulp mill lime kiln located at a kraft or soda 

facility, you must determine CO2, CH4, and N2O emissions using 
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the procedures in paragraphs (c)(1) through (c)(3) of this 

section:

(1) Calculate CO2 emissions from fossil fuel from direct 

measurement of fossil fuels consumed and default HHV and default 

emissions factors, according to the Tier 1 Calculation 

Methodology for stationary combustion sources in §98.33(a)(1). A 

higher tier from §98.33(a) may be used to calculate fossil fuelbased CO2 emissions if the respective monitoring and QA/QC 

requirements described in §98.34 are met.

(2) Calculate CH4 and N2O emissions from fossil fuel from 

direct measurement of fossil fuels consumed, default or sitespecific HHV, and default emissions factors and convert to 

metric tons of CO2 equivalent according to the methodology for 

stationary combustion sources in §98.33(c); use the default HHV 

listed in Table C–1 of subpart C and the default CH4 and N2O 

emissions factors listed in Table AA–2 of this subpart.

(3) Biogenic CO2 emissions from conversion of CaCO3to CaO 

are included in the biogenic CO2 estimates calculated for the 

chemical recovery furnace in paragraph (a)(3) of this section.

(d) For makeup chemical use, you must calculate CO2

emissions by using direct or indirect measurement of the 

quantity of chemicals added and ratios of the molecular weights 

of CO2 and the makeup chemicals, according to Equation AA–3 of 

this section:
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Where:

CO2 = CO2 mass emissions from makeup chemicals 

(kilograms/yr).

M (CaCO3) = Make-up quantity of CaCO3used for the reporting 

year (metric tons per year).

M (NaCO3) = Make-up quantity of Na2CO3used for the 

reporting year (metric tons per year).

44 = Molecular weight of CO2.

100 = Molecular weight of CaCO3.

105.99 = Molecular weight of Na2CO3.

§ 98.274 Monitoring and QA/QC requirements.

(a) Each facility subject to this subpart must quality 

assure the GHG emissions data according to the applicable 

requirements in §98.34. All QA/QC data must be available for 

inspection upon request.

(b) Fuel properties needed to perform the calculations in 

Equations AA–1 and AA–2 of this subpart must be determined 

according to paragraphs (b)(1) through (b)(3) of this section.

(1) High heat values of black liquor must be determined no 

less than annually using T684 om–06 Gross Heating Value of Black 

Liquor, TAPPI (incorporated by reference, see §98.7). If 

measurements are performed more frequently than annually, then 

the high heat value used in Equation AA–1 of this subpart must 

be based on the average of the representative measurements made 

during the year.
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(2) The annual mass of spent liquor solids must be 

determined using either of the methods specified in paragraph 

(b)(2)(i) or (b)(2)(ii) of this section.

(i) Measure the mass of spent liquor solids annually (or 

more frequently) using T–650 om–05 Solids Content of Black 

Liquor, TAPPI (incorporated by reference in §98.7). If 

measurements are performed more frequently than annually, then 

the mass of spent liquor solids used in Equation AA–1 of this 

subpart must be based on the average of the representative 

measurements made during the year.

(ii) Determine the annual mass of spent liquor solids based 

on records of measurements made with an online measurement 

system that determines the mass of spent liquor solids fired in 

a chemical recovery furnace or chemical recovery combustion 

unit.

(3) Carbon analyses for spent pulping liquor must be 

determined no less than annually using ASTM D5373–08 Standard 

Test Methods for Instrumental Determination of Carbon, Hydrogen, 

and Nitrogen in Laboratory Samples of Coal (incorporated by 

reference, see §98.7). If measurements using ASTM D5373–08 are 

performed more frequently than annually, then the spent pulping 

liquor carbon content used in Equation AA–2 of this subpart must 

be based on the average of the representative measurements made 

during the year.
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(c) Each facility must keep records that include a detailed 

explanation of how company records of measurements are used to 

estimate GHG emissions. The owner or operator must also document 

the procedures used to ensure the accuracy of the measurements 

of fuel, spent liquor solids, and makeup chemical usage, 

including, but not limited to calibration of weighing equipment, 

fuel flow meters, and other measurement devices. The estimated 

accuracy of measurements made with these devices must be 

recorded and the technical basis for these estimates must be 

provided. The procedures used to convert spent pulping liquor 

flow rates to units of mass (i.e., spent liquor solids firing 

rates) also must be documented.

(d) Records must be made available upon request for 

verification of the calculations and measurements.

§ 98.275 Procedures for estimating missing data.

A complete record of all measured parameters used in the 

GHG emissions calculations is required. Therefore, whenever a 

quality-assured value of a required parameter is unavailable 

(e.g., if a meter malfunctions during unit operation or if a 

required sample is not taken), a substitute data value for the 

missing parameter shall be used in the calculations, according 

to the requirements of paragraphs (a) through (c) of this 

section:
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(a) There are no missing data procedures for measurements 

of heat content and carbon content of spent pulping liquor. A 

re-test must be performed if the data from any annual 

measurements are determined to be invalid.

(b) For missing measurements of the mass of spent liquor 

solids or spent pulping liquor flow rates, use the lesser value 

of either the maximum mass or fuel flow rate for the combustion 

unit, or the maximum mass or flow rate that the fuel meter can 

measure.

(c) For the use of makeup chemicals (carbonates), the 

substitute data value shall be the best available estimate of 

makeup chemical consumption, based on available data (e.g., past 

accounting records, production rates). The owner or operator 

shall document and keep records of the procedures used for all 

such estimates.

§ 98.276 Data reporting requirements.

In addition to the information required by §98.3(c) and the 

applicable information required by §98.36, each annual report 

must contain the information in paragraphs (a) through (k) of 

this section as applicable:

(a) Annual emissions of CO2, biogenic CO2, CH4, biogenic CH4

N2O, and biogenic N2O (metric tons per year).

(b) Annual quantities fossil fuels by type used in chemical 

recovery furnaces and chemical recovery combustion units in 
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short tons for solid fuels, gallons for liquid fuels and scf for 

gaseous fuels.

(c) Annual mass of the spent liquor solids combusted (short 

tons per year), and basis for determining the annual mass of the 

spent liquor solids combusted (whether based on T650 om-05 

Solids Content of Black Liquor, TAPPI (incorporated by 

reference, see §98.7) or an online measurement system).

(d) The high heat value (HHV) of the spent liquor solids 

used in Equation AA–1 of this subpart (mmBtu per kilogram).

(e) The default emission factor for CO2, CH4, or N2O, used 

in Equation AA–1 of this subpart (kg CO2, CH4, or N2O per mmBtu).

(f) The carbon content (CC) of the spent liquor solids, 

used in Equation AA–2 of this subpart (percent by weight, 

expressed as a decimal fraction, e.g., 95% = 0.95).

(g) Annual quantities of fossil fuels by type used in pulp 

mill lime kilns in short tons for solid fuels, gallons for 

liquid fuels and scf for gaseous fuels.

(h) Make-up quantity of CaCO3 used for the reporting year 

(metric tons per year) used in Equation AA–3 of this subpart.

(i) Make-up quantity of Na2CO3 used for the reporting year 

(metric tons per year) used in Equation AA–3 of this subpart.

(j) Annual steam purchases (pounds of steam per year).

(k) Total annual production of unbleached virgin chemical

pulp produced onsite during the reporting year in air-dried 
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metric tons per year. This total annual production value is the 

sum of all kraft, semichemical, soda, and sulfite pulp produced 

onsite, prior to bleaching, through all virgin pulping lines. Do 

not include mechanical pulp or secondary fiber repulped for 

paper production in the virgin pulp production total. 

§ 98.277 Records that must be retained.

In addition to the information required by §98.3(g), you 

must retain the records in paragraphs (a) through (f) of this 

section.

(a) GHG emission estimates (including separate estimates of 

biogenic CO2) for each emissions source listed under §98.270(b).

(b) Annual analyses of spent pulping liquor HHV for each 

chemical recovery furnace at kraft and soda facilities.

(c) Annual analyses of spent pulping liquor carbon content 

for each chemical recovery combustion unit at a sulfite or 

semichemical pulp facility.

(d) Annual quantity of spent liquor solids combusted in 

each chemical recovery furnace and chemical recovery combustion 

unit, and the basis for detemining the annual quantity of the 

spent liquor solids combusted (whether based on T650 om–05 

Solids Content of Black Liquor, TAPPI (incorporated by 

reference, see §98.7) or an online measurement system). If an 

online measurement system is used, you must retain records of 
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the calculations used to determine the annual quantity of spent 

liquor solids combusted from the continuous measurements.

(e) Annual steam purchases.

(f) Annual quantities of makeup chemicals used.

§ 98.278 Definitions.

All terms used in this subpart have the same meaning given 

in the Clean Air Act and subpart A of this part.

Table AA–1 to Subpart AA of Part 98—Kraft Pulping Liquor 

Emissions Factors for Biomass-Based CO2, CH4, and N2O

Wood furnish

Biomass-based emissions factors

(kg/mmBtu HHV)

CO2

a CH4 N2O

North American Softwood 94.4 0.0019 0.00042

North American Hardwood 93.7 0.0019 0.00042

Bagasse 95.5 0.0019 0.00042

Bamboo 93.7 0.0019 0.00042

Straw 95.1 0.0019 0.00042

aIncludes emissions from both the recovery furnace and pulp mill lime kiln.

Table AA–2 to Subpart AA of Part 98—Kraft Lime Kiln and Calciner

Emissions Factors for CH4 and N2O

Fuel

Fossil fuel-based emissions factors (kg/mmBtu HHV)

Kraft lime kilns Kraft calciners

CH4 N2O CH4 N2O

Residual Oil

(any type)

0.0027 0 0.0027 0.0003

Distillate Oil

(any type)

0.0027 0 0.0027 0.0004

Natural Gas 0.0027 0 0.0027 0.0001

Biogas 0.0027 0 0.0027 0.0001
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Petroleum coke 0.0027 0 NAs NAa

Other Fuels See Table 

C-2

0 See Table

C-2

See Table

C-2

aEmission factors for kraft calciners are not available.