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3 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 5 

77 WEST JACKSON BOULEVARD 

CHICAGO, IL 60604-3590 

REPLY TO THE ATENTION OF: 

DATE : JAN 2 5 2009 

SUBJECT: Technical Support Document for the Approval of 

Wisconsin Nitrogen Oxides (NOx) Reasonably 

Available Control Technology (RACT) and Additions 

and Amendments to Other Non-RACT NOx Rules 

/-&if- FROM: Douglas Aburano, Environmental Engineer , 

Criteria Pollutant Section 

TO: Docket 

The Clean Air Act amendments of 1990 (CAA) introduced the 

requirement for existing major stationary sources of NOx in 

nonattainment areas to install and operate NOx RACT. 

Specifically, section 182(b)(2) of the CAA requires states 

to adopt RACT for all major sources of volatile organic 

compounds (VOC) in ozone nonattainment areas and section 

182(f) requires the RACT provisions for major stationary 

sources of oxides of nitrogen. 

Section 302 of the CAA defines major stationary source as 

any facility which has the potential to emit 100 tons or 

more per year of any air pollutant. For serious ozone 

nonattainment areas, a major source is defined by section 

182(c) as a source that has the potential to emit 50 tons 

or more of NOx per year. For severe ozone nonattainment 

areas, a major source is defined by section 182(d) as a 

source that has the potential to emit 25 tons per year. 

Since the only areas in Wisconsin that are required to 

adopt NOx RACT are classified as moderate, the rules that 

have been adopted only need to address sources with the 

potential to emit 100 tons or more per year. 

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2

Pursuant to sections 182(b)(2) and 182(f) of the Clean Air 

Act (CAA), Wisconsin is required to implement RACT for all 

major VOC and NOx sources in the Milwaukee-Racine area and 

Sheboygan County because they are classified as moderate. 

The other nonattainment areas are not classified high 

enough to have the RACT requirement. The major source 

threshold in moderate areas is 100 tons per year. 

Wisconsin’s Submittal 

The Wisconsin Department of Natural Resources (WDNR) 

submitted NOx RACT regulations for the Milwaukee-Racine and 

Sheboygan County areas on June 12, 2007 and September 14, 

2009. The WDNR held a public hearing for the June 12, 2007 

rules on March 15, 2007. WDNR also provided a comment 

period that was announced on February 2, 2007 and ended on 

March 19, 2007. The WDNR held a public hearing for the 

September 14, 2009 rules on December 5, 2008. WDNR also 

provided a comment period that was announced on October 30, 

2008 and ended on December 10, 2008. 

Additionally, WDNR submitted minor additions and amendments 

to other non-RACT NOx rules as part of the June 12, 2007 

and September 14, 2009 submittals. The non-RACT NOx rules 

that are being changed were originally approved into 

Wisconsin’s SIP on November 13, 2001 (66 FR 56931). These 

other NOx rules were submitted as part of Wisconsin’s 

reasonable further progress SIP for the 1-hour ozone 

standard. 

Summary of Wisconsin’s Rules 

June 12, 2007 Submittal

Chapter NR 428 of the Wisconsin Administrative Code 

Environmental Protection Air Pollution Control, entitled, 

“Control of Nitrogen Compound Emissions,” includes 

provisions limiting the emissions of NOx from stationary 

sources in Wisconsin. While Part NR 428 contains many 

sections, Wisconsin submitted only a portion of them to 

address the NOx RACT requirements, rules 428.20 through 

428.26 and 428.02(7m). Wisconsin submitted other non-RACT 

rules for approval because they are additions or amendments 

to rules already approved into the SIP. The other non-RACT 

rules submitted for approval are: 428.02(7m), 

428.04(2)(h)1. and 2., 428.05(3)(e)1. to 4., 484.04(13), 
3

484.04 (15m) and (16m),and 484.04(21m),(26m)(bm),(26m)(d) and 

(27) for federal approval. 

• Rule 428.02(7m),is part of the “Definitions” section. 

Rule 428.02(7m) creates the definition of “Process 

heater”. 

• Rules 428.04(2)(h)1.and 2.are part of the section, 

entitled “Requirements and performance standards for new 

or modified sources”. These rules have been corrected to 

use the units of “grams per brake horsepower-hour” from 

“grams per brake horsepower.” 

• Rules 428.05(3)(e)1.to 4,are part of the section, 

entitled “Requirements and performance standards for 

existing sources”. These rules have been corrected to use 

the units of “grams per brake horsepower-hour” from 

“grams per brake horsepower.” 

• Rule 428.20 through 428.26,are part of a newly created 

subchapter to address the NOx RACT requirements. This 

subchapter is entitled “Subchapter IV – NOx Reasonably 

Available Control Technology Requirements.” 

• Rule 428.20,entitled “Applicability and purpose,” 

establishes the geographic area and size and types of 

sources that the NOx RACT requirements apply to. 

• Rule 428.21, entitled “Emission unit exceptions” 

establishes the subset of sources that these rules will 

not apply to. 

• Rule 428.22,entitled “Emission limitation requirements,” 

establishes the emission limits for sources subject to 

these rules. 

• Rule 428.23,entitled “Demonstrating compliance with 

emission limitations,” establishes compliance methods for 

sources subject to these rules. 

• Rule 428.24,entitled “Recordkeeping and reporting,” 

establishes the recordkeeping and reporting requirements 

for sources subject to these rules. 

• Rule 428.25,entitled “Alternative compliance methods and 

approaches,” establishes the provisions describing the 

emissions averaging provisions and other alternative RACT 

requirements allowed for compliance. 

• Rule 428.26,entitled “Utility reliability waiver,” 

establishes the provisions under which utilities can 

request a waiver from emission limits under Subchapter IV 

given specific criteria. 

• Rule 484.04(13),is part of chapter NR 484, “Incorporation 

by reference” and a section entitled “Code of federal 

regulations appendices”. Rule 484.04(13) has been 
4

amended to reference 40 CFR Part 60 Appendix A for NR 

428.25(1)(b)4. 

• Rule 484.04(15m) and (16m), are part of chapter NR 484, 

“Incorporation by reference” and a section entitled “Code 

of federal regulations appendices”. Rules 484.04(15m) 

and (16m) have been created to reference 40 CFR Part 60 

Appendix A for NR 428.23(1)(b)3.a., NR 428.23(1)(b)2.d., 

5.a. and b. and 6.b. 

• Rule 484.04(21m), is part of chapter NR 484, 

“Incorporation by reference” and a section entitled “Code 

of federal regulations appendices”. Rule 484.04(21m) has 

been amended to reference 40 CFR Part 60 Appendix F for 

NR 428.23(1)(b)2.c. 

• Rule 484.04(26m)(bm), is part of chapter NR 484, 

“Incorporation by reference” and a section entitled “Code 

of federal regulations appendices”. Rules 484.04(26m) 

has been created to reference 40 CFR Part 75 Appendix E 

for NR 428.23(1)(2)e. 

• Rule 484.04(26m)(d) and (27), are part of chapter NR 484, 

“Incorporation by reference” and a section entitled “Code 

of federal regulations appendices”. Rules 484.04(26m)(d) 

and (27) have been amended to reference 40 CFR Part 75 

Appendix F for NR 428.23(1)(b)5.c. and 6.b.and c., and to 

reference 40 CFR Part 75 Appendices A to I for NR 

428.23(1)(b)1. 

September 14, 2009

Like the June 12, 2007 submittal, the September 14, 2009 

submittal contains both RACT and non-RACT rule additions 

and amendments. The same rules, 428.20 through 428.26, 

along with 428.02(7e) are being submitted for approval as 

RACT and the other rules are being submitted as 

miscellaneous changes to rules that have already been 

approved into the SIP. 

The following rules have been amended, renumbered or added: 

renumber and amend 428.22(1)(d); amend NR 428.04(1) and 

(3)(b), 428.05(1) and (4)(b)2., 428.07(intro.), (1)(a) and 

(b)1. and 3., (3) and (4)(c), 428.08(title) and (2)(title), 

428.09(2)(a), 428.20(1), 428.22(2)(intro.), 428.23(1)(b)1., 

428.24(1)(b)(intro.) and 428.25(1)(a)1.a. and c. and 

(3)(b); and to create NR 428.02(7e), 428.08(2)(f), 428.12, 

428.22(1)(d)2., and 428.23(1)(b)9., relating to 

modification of existing rules for control of nitrogen 

oxide (NOx) emitted by stationary sources in the ozone 

nonattainment area in southeastern Wisconsin. 
5

The revisions to the RACT rules do two things, they : 1) 

incorporate and add a definition of "maximum theoretical 

emissions" (MTE) in place of “potential to emit" (PTE) in 

order to adequately identify major sources; and 2) make 

revisions which clarify and facilitate implementation of 

requirements within ch. NR 428. 

There are a number of non-substantive revisions in the rule 

package that clarify implementation issues which are 

consistent with the original intent of the rules. The 

revisions to the June 12, 2007 submittal do not alter the 

primary emission limitations or alter those individual 

emissions units subject to emission requirements. These 

revisions include: 

 

• Removal of the reference to the federal Clean Air 

Interstate Rule (CAIR) and application of standard terms 

in identifying the appropriate units. 

• Allowance of additional time for sources to submit an 

application for an alternative emission limit or 

compliance schedule. 

• Allowance for a source with an approved alternative RACT 

requirement to participate in emissions averaging for 

purposes of demonstrating compliance with the original 

RACT limitation or schedule. 

• Avoiding triggering new source NOx limits under s. NR 

428.04 when the modification is made solely to comply 

with existing source NOx control requirements under ss. 

NR 428.05 or 428.22. 

• Clarification and simplification of monitoring and 

reporting requirements. 

• The applicability statement in s. NR 428.05(1) is being 

revised to remove the reference to “modified" sources. 

• The Department identifies limited periods when the 

current form of the emission limitation for glass 

furnaces is not appropriate. During these periods the 

numerical emission limit does not apply. Instead, the 

source is required to minimize NOx emissions through 

combustion optimization techniques described in s. NR 

439.096. 

C. Review of Wisconsin's RACT Submittal 

Background 
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The Clean Air Act requirements are described by EPA in a 

document entitled, “State Implementation Plans; Nitrogen 

Oxides Supplement to the General Preamble; Clean Air Act 

Amendments of 1990 Implementation of Title I; Proposed 

Rule,” published November 25, 1992, also known as the NOx 

Supplement, should be referred to for more detailed 

information on NOx requirements. Additional EPA guidance 

memoranda, such as those included in the “NOx Policy 

Document for the Clean Air Act of 1990,” (EPA-452/R-96-005, 

March 1996), should also be referred to for more 

information on NOx requirements. These are the documents 

EPA used to review Wisconsin’s NOx RACT submittal. 

The WDNR created Subchapter IV entitled “NOx Reasonably 

Available Control Technology Requirements” to address the 

NOx RACT requirements of the Clean Air Act. Subchapter IV 

consists of rules 428.20 through 428.26. Additional 

provisions of 428.02(7e) and (7m) were also created to 

support the Subchapter IV RACT requirements. 

Rules 428.01, 428.02, 428.04, 428.05 and 428.07 through 

428.11 were originally approved into the Wisconsin SIP to 

fulfill Reasonable Further Progress requirements for 1-hour 

ozone nonattainment areas (66 FR 56931). Rules 

428.02(6m), 428.04(2)(g)(3) and 428.06 were later approved 

(68 FR 17551). Rules 428.02(1) and (1m), 428.04(2)(g)(1), 

428.04(2)(g)(4), and 428.06(2)(a) were then approved (70 FR 

22259). Minor additions and changes have been made to 

these rules and WDNR has requested approval of these 

additions and amendments into the SIP. 

NR 428.20 Applicability 

Rule 428.20 “Applicability and Purpose” establishes the 

geographic scope of the rule and the sources that are 

subject to the rule. The rules apply in the nonattainment 

areas that are classified as moderate under the 1997 8-hour 

ozone standard. Therefore, the rules apply in the 

Milwaukee-Racine area (Kewaunee County, Milwaukee County, 

Ozaukee County, Racine County, Washington County and 

Waukesha County) and Sheboygan County. The requirements 

apply to the owner or operator of a NOx emissions unit 

which is located at a facility with a combined total 

maximum theoretical emissions for all NOx emissions units 

of 100 tons per year or more. This is consistent with the 

Clean Air Act and EPA guidance. Rule 428.20 refers to 

Wisconsin’s definition of “Maximum theoretical emissions” 
7

found in Wisconsin rule NR 428.02(7e). These two rules, in 

combination, satisfy the requirements for adequate 

applicability in terms of geographic coverage and the types 

and sizes of sources covered. 

NR 428.21 Exemptions 

Rule 428.21, entitled “Emission unit exceptions” 

establishes a number of default exemptions from the 

emission limits for units meeting certain conditions. The 

exemptions streamline compliance by identifying sources for 

which control cost-effectiveness is beyond that considered 

in the rule. These sources otherwise would likely apply 

for a variance to the RACT requirement. The rule 

identifies minimal recordkeeping requirements to ensure 

continued qualification under the applicable exemption. 

There are generally two bases for the exemptions: 1) unit 

types or applications with low operation levels; and 2) 

units which are meeting the emission limit and have 

sufficient monitoring requirements in place or are well 

controlled and for which the incremental control to meet 

the RACT emission limit is significantly more costly. 

Specifcally: 

“(1) GENERAL EXEMPTIONS. The following emissions units 

and processes are exempt from the emission limitations in 

s. NR 428.22: 

(a) Any emissions unit operated only to restart 

electric generation in the event of a complete loss of 

facility power. 

(b) Any emissions unit which is operated no more than 

500 hours per year and no more than 200 hours during 

the ozone season and whose only purpose is to provide 

electricity to a facility if normal electricity 

service is interrupted or to replace normal critical 

operations at a facility. 

(c) Any emissions unit whose only function is to pump 

water in the case of a fire emergency. 

(d) Any emissions unit whose utilization is less than 

10% of its capacity factor on an annual average basis 

over a 3-year rolling period and less than 20% of its 

capacity factor in any year of the 3-year rolling 

period and which is owned or operated by an electric 

generation utility or gas transmission utility. 

(e) A research or development unit. 
8

(f) An engine testing operation or process line. 

(g) Any gaseous fuel fired unit used to control VOC 

emissions from a commercial or industrial process. 

(2) LOW OPERATING UNIT. An emissions unit described in s. 

NR 428.20 is exempt from the emission limitations of s. 

NR 428.22 if, during each ozone season, the emissions 

unit's utilization based on actual measured heat input or 

output is less than the utilization threshold for the 

source category according to the following equation: 

UUi < (Category capacity ) x (3,672 hours / Ozone Season ) x Capacity Factor 

where: 

UUi is the unit's actual fuel consumption or output in 

measurement units consistent with the calculated 

utilization threshold for the source category in s. NR 

428.22 

Category capacity is the lower value in the range of unit 

capacity or design output used to describe the unit’s 

source category i in s. NR 428.22 

Capacity factor is 0.20 for all source categories in s. 

NR 428.22 

(2m) RECIPROCATING ENGINES. Any reciprocating engine that 

is certified to meet the applicable federal non-road 

engine emission standards specified in this subsection is 

exempt from the emission limitations of s. NR 

428.22(1)(i): 

(a) A reciprocating compression ignition engine that 

is certified as meeting Tier 1 requirements as 

specified in 40 CFR part 89, if one of the following 

applies: 

1. The engine has a maximum design power output of 

less than 2,000 horsepower. 

2. The engine has a maximum design power output 

equal to or greater than 2,000 horsepower and has a 

total utilization during each ozone season of less 

than 1.5 million horsepower-hours, based on actual 

measured output. 

(b) A reciprocating compression ignition engine that 

is certified as meeting the Tier 2 standard, as 

specified in 40 CFR part 89, or a reciprocating 

compression ignition engine that is certified as 
9

meeting the requirements of a more stringent Tier 

standard, as specified in 40 CFR part 89 or 1039. 

(c) A reciprocating spark ignition engine that is 

certified as meeting the Tier 1 standard or a 

reciprocating spark ignition engine that is certified 

as meeting a more stringent Tier standard, as 

specified in 40 CFR part 1048. 

(3) OTHER REGULATED UNIT. An emissions unit which is 

subject to and meeting an emission limitation in s. NR 

428.04 or 428.05(3) is exempt from the emission 

limitations in s. NR 428.22, if one of the following 

applies: 

(a) The emissions unit is subject to a federally 

enforceable condition in an air permit which limits 

its emissions to no more than 75 tons of NOX per year. 

(b) The emissions unit, because of a physical 

operating constraint, cannot emit more than 75 tons of 

NOX per year.” 

Because the specific units that qualify for these 

exemptions are estimated to incur costs significantly 

greater than $2,500/ton, the exemptions, as described above 

are acceptable. An explanation of why the $2,500/ton 

threshold was chosen is given below in the description of 

“NR 428.22 Emission Limits”. 

The one exemption not based on cost-effectiveness but 

rather on technical issues is the exemption under s. NR 

428.21(g) for a "gaseous fuel fired unit used to control 

VOC emissions" The primary consideration in design and 

operation of such an emissions unit is for the efficient 

destruction of VOC emissions and not to minimize NOx 

emissions. For this reason this exemption is appropriate. 

NR 428.22 Emission Limits 

Rule 428.22, entitled “Emission limitation requirements,” 

establishes the emission limits for sources subject to 

these rules. 

The rule establishes NOx emission rate limits by source 

category applicable to individual emission units. The 

emission limits must be complied with on a 30-day rolling 

average basis throughout the year. 
10

Wisconsin’s rule requires compliance with these limits 

beginning on May 1, 2009. 

WDNR looked to the 8-hour Ozone Implementation Guidance (70 

FR 71654) in determining the cost range of controls 

considered for NOx RACT. This guidance referred to 1994 

EPA guidance that considered a 30-50% reduction within a 

cost range of $160-1,300 per ton of NOx removed as RACT. 

$1,300/ton adjusted using the consumer price index is 

approximately $2,000/ton in 2005 dollars. For their 

evaluation of RACT, WDNR assumed an upper limit of 

approximately $2,500 per ton in estimating applicable RACT 

controls. 

We have found that these limits taking cost-effectiveness 

into consideration are consistent with EPA guidance for the 

various categories for which Alternative Control Technology 

documents have been issued. They are also consistent with 

other RACT limits in other states. 

For solid fuel-fired boilers, the emission limits range 

from .10 lb/mmBtu to .25 lb/mmBtu based on boiler type and 

size. 

Lime kiln limits are as follows: 

1. For a gaseous fuel-fired unit, 0.10 pound per mmBtu of 

heat input. 

2. For a distillate oil-fired unit, 0.12 pound per mmBtu 

of heat input. 

3. For a residual oil-fired unit, 0.15 pound per mmBtu of 

heat input. 

4. For a coal-fired unit, 0.60 pound per mmBtu of heat 

input. 

5. For a coke-fired unit, 0.70 pound per mmBtu of heat 

input. 

These limits apply to lime kilns with a maximum heat input 

capacity equal to or greater than 50 mmBtu/hour. 

Reheat, annealing or galvanizing furnaces with a maximum 

heat input capacity equal to or greater than 75 mmBtu/hour 

are limited to 0.08 lb/mmBtu. 

Glass furnaces with a maximum heat input capacity equal to 

or greater than 50 mmBtu per hour, are limited to 2.0 

pounds per ton of produced glass. During periods when the 
11

furnace is operating for purposes other than producing 

glass, NOx emissions must be minimized (refer to 

modifications in the September 14, 2007 submittal). 

Asphalt plants with a maximum heat input capacity equal to 

or greater than 65 mmBtu per hour, are required to meet one 

of the following as applicable: 

1. For a gaseous fuel-fired unit, 0.15 pound per million 

Btu of heat input. 

2. For a distillate fuel oil-fired unit, 0.20 pound per 

million Btu of heat input. 

3. For a residual fuel oil-fired or waste oil-fired unit, 

0.27 pound per million Btu of heat input. 

Process heaters, dryers, ovens or other process heating 

devices, are required to meet one of the following as 

applicable: 

1. For a gaseous fuel-fired unit with a maximum heat 

input capacity equal to or greater than 100 mmBtu per 

hour, 0.10 pound per mmBtu of heat input. 

2. For a distillate oil-fired unit with a maximum heat 

input capacity equal to or greater than 100 mmBtu per 

hour, 0.12 pound per mmBtu of heat input. 

3. For a residual oil-fired unit with a maximum heat 

input capacity equal to or greater than 65 mmBtu per 

hour, 0.18 pound per mmBtu of heat input. 

Simple cycle combustion turbines shall meet one of the 

following exhaust outlet concentrations, corrected to 15% O2

and at ambient temperatures greater than 0oF, as applicable: 

1. For a unit with a maximum design power output equal to 

or greater than 50 megawatts, one of the following, as 

applicable: 

a. If natural gas-fired, 25 parts per million dry 

volume. 

b. If distillate oil fuel-fired, 65 parts per million 

dry volume. 

c. If biologically derived gaseous fuel-fired, 35 

parts per million dry volume. 

2. For a unit with a maximum design power output equal to 

or greater than 25 megawatts and less than 50 megawatts, 

one of the following as applicable: 
12

a. If natural gas-fired, 42 parts per million dry 

volume. 

b. If distillate oil fuel-fired, 96 parts per million 

dry volume. 

c. If biologically derived gaseous fuel-fired, 35 

parts per million dry volume. 

Combined cycle combustion turbines shall meet one of the 

following exhaust outlet concentrations, corrected to 15% O2

and at ambient temperatures greater than 0oF, as applicable: 

1. For a natural gas-fired unit with a maximum design 

power output equal to or greater than 25 megawatts, 9 

parts per million dry volume. 

2. For a natural gas-fired unit with a maximum design 

power output equal to or greater than 10 megawatts and 

less than 25 megawatts, 42 parts per million dry volume. 

3. For a distillate oil fuel-fired unit with a maximum 

design power output equal to or greater than 10 

megawatts, 42 parts per million dry volume. 

4. For a biologically derived gaseous fuel-fired unit 

with a maximum design power output equal to or greater 

than 10 megawatts, 35 parts per million dry volume. 

Reciprocating engines with a maximum design power output 

equal to or greater than 500 horsepower shall meet one of 

the following as applicable: 

1. For a rich-burn spark ignition unit, 3.0 grams per 

brake horsepower-hour. 

2. For a lean-burn spark ignition unit, 3.0 grams per 

brake horsepower-hour. 

3. For a diesel fuel-fired compression unit, 3.0 grams 

per brake horsepower-hour. 

4. For a dual fuel-fired compression unit, 3.0 grams per 

brake horsepower-hour. 

Electric utility boilers For electric utility coal-fired 

boilers the rule sets a phased compliance schedule with 

interim emission limits for May 1, 2009 and final RACT 

emission limits by May 1, 2013. The schedule of phased 

limitations is provided in Table 2. 

The purpose of the phased compliance schedule is to allow 

the electric utilities the necessary time to install post 

combustion controls while maintaining a reliable electric 
13

supply. Some control technologies, like selective 

catalytic reduction equipment, can take up to two years to 

install for an individual project. This is compounded by 

the fact that utilities are subject to limited installation 

windows which further restrict the installation schedule. 

On this basis, multiple installations cannot be fully 

accomplished on all electric utility boilers within the 

moderate nonattainment area by 2009. 

The emission limits for 2009 reflect NOx controls which can 

be installed within the intervening timeframe including 

combustion modifications and selective non-catalytic 

reduction systems. The final 2013 compliance date reflects 

the timing necessary for anticipated installations of 

selective catalytic reduction systems. The phased approach 

is also consistent with operating generating units on a 

system-wide basis and utilization of a multi-facility 

averaging program. In this manner, the phased emission 

limits set forth a RACT level of NOx control across 

utilities boilers on a schedule which is expeditious as 

practicable. 

 

Table 2. Compliance Schedule for Electric 

Utility Coal-Fired Boilers 

Emission Limits (lbs/mmbtu) 

Compliance 

Date Coal-fired Boilers > 

1000 mmbtu/hr 

Coal-fired Boilers 

>500 and <1000 

mmbtu/hr 

May 1, 

2009 

wall fired = 0.15 

tangential fired = 

0.15 

cyclone = 0.15 

fluidized bed = 0.15

arch fired = 0.18 

wall fired = 0.20 

tangential fired = 

0.15 

cyclone = 0.20 

fluidized bed = 

0.15 

arch fired = 0.18 

May 1, 

2013 

wall fired = 0.10 

tangential fired = 

0.10 

cyclone = 0.10 

fluidized bed = 0.10

arch fired = 0.18 

wall fired = 0.17 

tangential fired = 

0.15 

cyclone = 0.15 

fluidized bed 

=0.10 

arch fired = 0.18 
14

It should be noted that arch fired boilers have the same 

limit in 2009 as in 2013. This is because RACT for arch 

fired boilers (tertiary air) can be implemented by the 2009 

date and no additional controls are necessary. Other 

boiler types are expected to implement add-on controls that 

will reduce emissions from 2009 to 2013 and this is 

reflected in their emission limits. 

Since the RACT emission limits are implemented on a 

schedule which is as expeditious as practicable the 

proposed phasing of electric utility boiler emission limits 

is acceptable. This approach has been approved by EPA for 

other RACT programs. 

NR 428.23 Compliance 

The rule requires compliance monitoring, record keeping, 

and reporting specified for each source category. For 

units already required to do so, emissions are to be 

measured according to Part 75 CEMs monitoring requirements. 

Remaining units are specified by source category to either 

install and operate continuous NOx emission monitors 

according to 40 CFR Part 60 methods or perform stack 

testing every two years. The rule specifies the methods 

and calculations to tabulate emissions under each 

requirement. Units which may emit over 3 lbs. per hour or 

15 lbs. per day of NOx are required to have a malfunction 

and abatement plan for the monitoring system. 

Monitors are required to be installed by April 1, 2009 or 

by April 1 of the year a unit becomes subject to an 

emission limit in Rule 428.22. 

The rule requires most source categories subject to 

emission limitations to demonstrate compliance using 

continuous emissions monitoring. For electric utility 

(EGU) sources this monitoring is based on 40 CFR part 75 

methods and for industrial source monitoring is based on 40 

CFR part 60 methods. For a few source categories with low 

variability in operations or emission rates, compliance is 

demonstrated by periodic stack testing. The emission 

monitoring requirements are consistent with existing state 

and EPA programs. The rule will also allow a source to 

request approval of an alternative monitoring method that, 

in addition to WDNR approval, must be approved by EPA. 
15

Boilers, lime kilns, reheat, annealing or galvanizing 

furnaces, and glass furnaces are required to follow the 

monitoring requirements from 40 CFR Part 60 that have been 

adopted. 

Asphalt plants, process heaters, simple cycle combustion 

turbines, combined cycle combustion turbines and 

reciprocating engines are required to conduct an initial 

performance emissions test and periodic emissions 

performance tests every two years thereafter.

NR 428.24 Recordkeeping and Reporting

All owners and operators of units subject to a an emission 

limit in NR 428.22 are required to maintain records and 

submit reports that will demonstrate compliance with those 

emission limits or can be used to identify periods of noncompliance. 

Units subject to emission limits are required to keep 

records of fuel usage, heat input, the 30-day rolling 

average emission rate, capacity utilization (on an ozone 

season basis and an annual basis) and maintenance records 

of the monitoring system. 

Reports documenting compliance, or noncompliance, with the 

emission limits are required. On an monthly basis, subject 

units are required to report the highest 30-day rolling 

average emission rate. On an ozone season and annual 

bases, operational parameters of both the unit and 

monitoring devices will also be reported. 

Units that qualify as exempt are required to record and 

maintain emissions unit operating data onsite which 

certifies continued qualification with the exemption 

status. 

These recordkeeping and reporting requirements are 

approvable. 

NR 428.25 Alternative compliance methods and approaches

NR 428.25 provides several compliance options. These 

options include emissions averaging, a case-by-case RACT 

determination, and a CAIR equivalency provision. These 

programs are structured to meet EPA's guidance for economic 
16

incentive programs, public notification and review, and EPA 

approval requirements. 

1) Emissions average. Emissions from one or more units 

subject to a RACT emission limitation may be averaged with 

other similar units at an affected facility. Except for 

"new units", which are excluded from averaging, all similar 

units, both RACT and non-RACT affected units, at a facility 

must be included in the averaging program. This is to 

eliminate a potential shift in generation/ production to 

any unit not subject to the RACT requirements. 

The emissions averaging applies the current applicable 

emission limit (or a fixed historic emission rate for nonRACT units) of each unit on a heat input weighted basis to 

determine an average facility or system emission limit. 

This averaging emission limitation is determined on an 

ozone season and annual basis. 

In both the facility and multi-facility cases, the longer 

averaging periods (the length of the ozone season and 

annually) are integral to the development of the averaging 

programs (programmatic) in several respects and are 

therefore acceptable. The longer averaging periods 

considers that the proposed emission limits are more 

stringent than historic NOx RACT programs and are set on a 

30 day rolling average basis. There are inherent 

difficulties associated with monitoring and showing 

compliance for averaging multiple units over shorter 

compliance periods or on a rolling average basis. Also, in 

this case where there is a limited pool of sources and with 

the lower emission limits there is less ability to leave 

sources uncontrolled under the averaging program. Rather, 

averaging addresses the last margins of control between 

sources or provides the ability to accommodate 

installations of controls on multiple units such as those 

addressed by the phasing of electric utility units. In 

these cases, the longer averaging periods are appropriate 

in which already low emitting sources further reduce 

emission levels in order to offset emissions from other 

sources. 

 

The EPA requires that averaging programs like those in the 

rule have an additional emission reduction as an 

environmental benefit in lieu of the provided flexibility. 

(See Improving Air Quality with Economic Incentive 

Programs, EPA-452/R-01-001, Jan. 2001.) When averaging 
17

emission units at one facility the rule requires an 

environmental benefit of an annual and ozone season mass 

cap. When averaging units across multiple facilities the 

environmental benefit is the EPA default of 10% reduction 

in the annual and ozone season emission rate. The 

environmental benefit under both averaging approaches 

becomes effective beginning in 2013. Applying the 

environmental benefit earlier than this date is not 

consistent with the need for phasing of emission limits 

applicable to electric utility emission units. 

Because the averaging periods are programmatic and 

incorporate the required "environmental benefit" as well as 

meeting other EPA requirements for public notice and 

compliance, the proposed averaging provisions are 

acceptable. In addition, the averaging allowed under these 

NOx RACT rules, after the environmental benefit is 

required, in all cases, results in lower total emissions 

during the ozone season and annually than units meeting the 

limits on an individual basis. In this respect this NOx 

RACT program is more restrictive in averaging during the 

ozone season than that allowed for RACT sources under the 

NOx SIP Call and the recently vacated CAIR rule. 

Therefore, it makes sense to allow these averaging 

provisions given the environmental benefit of lower 

emission limits. 

Facility Averaging 

As one of the alternative compliance options, Wisconsin’s 

rules offer averaging within a facility given the following 

conditions: 

• Emissions from one or more units subject to a RACT 

emission limitation may be averaged with other similar 

units at an affected facility. 

• Under this approach all similar units at the facility 

must be included in the averaging program unless 

meeting a RACT emission limit separately. This 

eliminates any potential shift in generation/ 

production to units not subject to the RACT 

requirements. 

• Emissions averaging applies the current applicable 

emission limit of each unit on a heat input weighted 

basis to determine an average facility or system 

emission limit. 
18

• The proposed environmental benefit is a mass cap on 

the affected emission units beginning in 2013 

Section 16.7 “Area-wide RACT provisions” of the EIP 

guidance allows for the use of an EIP to meet RACT 

requirements. Section 16.7 refers to section 4.3 “How must 

my EIP meet the environmental benefit principle?” which 

describe the environmental benefit that would be derived 

from application of an EIP. 

In the case of facility averaging, the environmental 

benefit is the implementation of an ozone season mass cap 

and an annual mass cap. Both caps are calculated using 

RACT emission rate limit multiplied by the average of the 

three years of highest heat input from 2000 to 2005. By 

using this mass cap approach, the future emissions are 

limited to a greater degree than a scenario where an EIP is 

not in place and sources are allowed to operate at maximum 

capacity with only an emission rate limit in place. 

The requirement of the mass cap environmental benefit 

begins in 2013 when all of the EGU controls are expected to 

be in place and the final EGU limits are to be complied 

with. A number of variables were addressed in determining 

the final emission rates for EGUs, included among them were 

the dates by which controls could be installed and another 

is that both facility and multi-facility averaging would be 

allowed as a compliance option. 

Section 16.13 “Provisions for EIPs that include RACT 

sources” requires the following: 

For Economic Incentive Programs(EIPs) that affect VOC and 

NOx for ozone purposes the EIP must: 

• have an averaging time of no more than 30 days, 

o This seems to be contradicted by the requirement 

listed below for NOx EIPs that are required to 

comply with the NOx SIP Call (or in this case, 

the CAIR). 

o The longer averaging periods are based on lower 

RACT emission limits, limited pool of sources, 

control equipment installation requirements, and 

technical issues related to monitoring and 

averaging over multiple units over short periods 

on a rolling basis. 
19

• prohibit emission reductions created outside the ozone 

season from being used during the ozone season, and 

o This has been done through the use of mass caps 

on an ozone season and an annual basis. 

• within an Open Market Trading (OMT) EIP, limit 

Discrete Emission Reductions (DERs) created in 1 year 

to use the same or in a subsequent year, subject to 

the restrictions of all applicable requirements. 

o This does not apply in this case. 

Section 16.13 goes on for NOx sources that are required to 

comply with the NOx MOU regulation or the NOx SIP call, the 

averaging time of an emission limit must not exceed a 

compliance period of an area’s ozone season. [While 

Wisconsin is not subject to either the NOx MOU regulation 

or the NOx SIP Call, it was subject to CAIR at the time 

these NOx RACT rules were adopted. As the NOx SIP Call 

requirements were to have been subsumed by the CAIR 

requirements, it stands to reason that sources subject to 

CAIR would be subject to the same requirements as the NOx 

SIP Call.] 

Sources involved with EIP trades must meet all requirements 

applicable to the program. The averaging time for any 

specified emission rate limits for trading purposes shall 

be consistent with: 

• attaining and maintaining all applicable NAAQS, 

o The averaging time is consistent with attaining 

the applicable NAAQS, specifically ozone as there 

is an ozone season mass cap, similar to the NOx 

SIP Call or CAIR. 

• meeting Reasonable Further Progress/Rate-of-Progress 

(RFP/ROP)requirements, and 

o The averaging time does not interfere with 

RFP/ROP requirements. 

• ensuring equivalency with all applicable RACT 

requirements (e.g. calculated coating of solid applied 

basis, use of the more stringent of the actual or 

allowable baselines, etc.). 

o Wisconsin’s RACT rule goes beyond equivalency 

with the applicable RACT requirements by setting 

a mass cap based on historical heat input. 

Multi-facility Averaging 
20

Wisconsin also offers averaging across multiple facilities 

as a compliance option given the following conditions: 

• Emissions units may participate in an emission 

averaging program across multiple units and 

facilities. 

• Each unit can only participate in one type of 

averaging program on an annual basis (facility or 

system-wide). 

• The proposed environmental benefit is the EPA default 

of 10% reduction in the emission rate on an annual and 

an ozone season basis, beginning in 2013. 

Section 16.7 “Area-wide RACT provisions” of the EIP 

guidance allows for the use of an EIP to meet RACT 

requirements. Section 16.7 refers to section 4.3 “How must 

my EIP meet the environmental benefit principle?” which 

describes the environmental benefit that would be derived 

from application of an EIP. 

In the case of multi-facility averaging, the environmental 

benefit is a 10% reduction in the emission rate on an 

annual and an ozone season basis. The environmental 

benefit of 10% begins in 2013 when all of the EGU controls 

are expected to be in place and the final EGU limits are to 

be complied with. A number of variables were addressed in 

determining the final emission rates for EGUs, included 

among them were the dates by which controls could be 

installed and another is that both facility and multifacility averaging would be allowed as a compliance option. 

The aggregate emission limitations are calculated as 

follows: 

( ) 1 EBF

HI

HI EL

EL n

u 1

u

n

u 1

u u

aggr = × −

∑

∑

=

=

 

where: 

• ELaggr is the aggregate emission limit in aggregate for 

all emissions units on an annual or ozone season basis 

• HIu is the heat input for each emissions unit, u, for 

the specified period of time 
21

• ELu is the emission limit for each emissions unit, u. 

For emission limitations in units other than heat 

input, the emission limitations shall be converted to 

a heat input basis. 

• EBF is the environmental benefit factor. For averaging 

programs effective on or after January 1, 2013, the 

EBF is 10% for the annual emission limit and 10% for 

the ozone season emission limit. Prior to this date 

the EBF is 0%. 

Section 16.13 “Provisions for EIPs that include RACT 

sources” requires the following: 

For EIPs that affect VOC and NOx for ozone purposes the EIP 

must: 

• have an averaging time of no more than 30 days, 

o This seems to be contradicted by the requirement 

listed below for NOx that are required to comply 

with the NOx SIP Call (or in this case, CAIR) 

o The longer proposed averaging periods are based 

on lower RACT emission limits, limited pool of 

sources, control equipment installation 

requirements, and technical issues related to 

monitoring and averaging over multiple units over 

short periods on a rolling basis. 

• prohibit emission reductions created outside the ozone 

season from being used during the ozone season, and 

o This has been done through the implementation of 

the ozone season averaging period. 

• within an OMT EIP, limit DERs created in one year to 

use the same or in a subsequent year, subject to the 

restrictions of all applicable requirements. 

o This does not apply in this case. 

Section 16.13 goes on for NOx sources that are required to 

comply with the NOx MOU regulation or the NOx SIP call, the 

averaging time of an emission limit must not exceed a 

compliance period of an area’s ozone season. [While 

Wisconsin is not subject to either the NOx MOU regulation 

or the NOx SIP Call, it was subject to CAIR at the time the 

NOx RACT rules were adopted. As the NOx SIP Call 

requirements were to have been subsumed by the CAIR 

requirements, it stands to reason that sources subject to 

CAIR would be subject to the same requirements as the NOx 

SIP Call.] 
22

Sources involved with EIP trades must meet all requirements 

applicable to the program. The averaging time for any 

specified emission rate limits for trading purposes shall 

be consistent with: 

• attaining and maintaining all applicable NAAQS, 

o The averaging time is consistent with attaining 

the applicable NAAQS, specifically ozone as there 

is an ozone season mass cap, similar to the NOx 

SIP Call. 

• meeting RFP/ROP requirements, and 

o The averaging time does not interfere with 

RFP/ROP requirements. 

• ensuring equivalency with all applicable RACT 

requirements (e.g. calculated coating of solid applied 

basis, use of the more stringent of the actual or 

allowable baselines, etc.). 

Wisconsin’s RACT rule meets these requirements with the 

applicable RACT requirements by providing a 10% 

environmental benefit reduction that applies to the units 

participating in a multi-facility averaging program. 

2) CAIR emissions units. 

We find all of the portions or NR 428.25 approvable except 

for NR 428.25(2). NR 428.25(2) would allow sources subject 

to CAIR to demonstrate compliance with RACT requirements by 

virtue of meeting the CAIR requirements. We cannot approve 

this portion of Wisconsin’s submittal at this point because 

CAIR has been remanded to EPA and we do not know if CAIR or 

the replacement rule for CAIR will be a substitute for RACT 

or not. 

3) Alternative RACT requirement. 

Wisconsin’s NOx RACT rules also offer an individual source 

the option to request an alternative emission limitation or 

compliance schedule, with a determination made on a caseby-case basis by the Department and by EPA. An alternative 

emission limit may be the result of an engineering 

assessment that demonstrates RACT controls are not 

economically or technically feasible for that unit. Any 

determination of an alternative limit or schedule must also 

account for a unit’s ability to participate in either a 

facility or system-wide emissions averaging program. 
23

Since any alternative RACT requirement must be approved by 

EPA as well, these provisions are acceptable as currently 

written. 

NR 428.26 Utility reliability waiver 

The rule contains a provision that allows an electric or 

steam utility or natural gas transmission facilities to 

request a waiver from an applicable emission limit for a 

period of time due to reliability issues. This provision 

acknowledges that these facilities serve non-interruptible 

customers and uncontrollable events may occur which result 

in an increase in emissions. Facilities generating steam 

for process and manufacturing purposes are not eligible for 

the waiver. This provision is acceptable because it 

requires consultation with both EPA and the Wisconsin 

Public Service before a determination can be made that the 

waiver will be granted. 

D. Review of Wisconsin’s Non-RACT Submittals 

A number of NOx regulations were approved into the 

Wisconsin SIP on November 13, 2001 (66 FR 56931). They 

were approved as part of the reasonable further progress 

requirements for the Milwaukee-Racine and Sheboygan County 

1-hour ozone nonattainment areas. The following changes 

were made to the "non-RACT" portions of ch. NR 428: 

NR 428.02 “Definitions” adds the definition of “process 

heater”, rule NR 428.02(7e). This addition is acceptable. 

NR 428.04(2)(h)1. and 2.,428.05(3)(e)1. to 4,have been 

corrected to use the units of “grams per brake horsepowerhour” from “grams per brake horsepower.” These corrections 

are acceptable. 

The revision avoids triggering new source NOx limits under 

s. NR 428.04 when the modification is made solely to comply 

with existing source NOx control requirements under ss. NR 

428.05 or 428.22. This modification does not alter the 

original intended emission limitation of the rule and 

therefore is acceptable. 

A number of clarifications and simplifications were made to 

the monitoring and reporting requirements under 

428.23(1)(b)1., 428.23(1)(b)9, and 428.24(1)(b)(intro.). 
24

These changes are not substantive in nature nor do they 

eliminate dual requirements. Therefore these modifications 

are acceptable. 

The applicability statement in s. NR 428.05(1) is being 

revised to remove the reference to “modified" sources. The 

use of the term "modified" in this case states that a 

source modified before the February 1, 2001 is an existing 

source. Some inferred this meant a source existing prior 

to that date but modified afterwards is not subject to an 

emission limit. The applicability language is altered to 

clearly identify units subject to an existing source 

emission limitation. This correction is acceptable.