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Costs and Benefits

- Can EPA please clarify whether or not the new cost/benefit estimates for the boilers and 

incinerator rules account for changes made in the NHSM definitions rule, which would 

affect the scope of units covered by each of the other rules? If not, does the agency have 

a sense for how much those changes would affect the costs/benefit estimates?

- How long would it take for EPA to provide an updated RIA for the rule? Given the 

magnitude of the changes made from the prior final rule, the level of detail on the costs 

and benefits in the RIA cover memo is insufficient.

- In a change from the proposal, EPA is not extending the compliance deadlines for units 

that are Gas 1 (natural gas/refinery gas), limited use, or has heat input capacity < 10

MMBtu/h and subject to the tune-up requirement. Can you explain for us why this 

change is not anticipated to cause compliance feasibility problems for these units? (For 

example, are these categories of units ones that need less lead time due to the nature of 

their compliance requirements?) Is this change based on comments received during the 

public comment period? 

CEMS Feasibility and Hg Limit

- In the proposed final rule, EPA added the use of continuous emission monitors (CEMS) 

as an option for meeting compliance requirements, and it sought comments on that 

additional option. A commenter notes that the Hg emission limit for new or 

reconstructed boilers in the final rule may at the lower limit of what commercial CEMS 

can reliably measure. For example, the Hg emission limit for new or reconstructed 

boilers, as shown in “Table 1 to Subpart DDDDD of Part 63—Emission Limits for New 

or Reconstructed Boilers and Process Heaters (Units with heat input capacity of 10 

million Btu per hour or greater)” is 8.0 x 10-7Lb/mmBtu heat input. Depending on the 

boiler efficiency, this may be at the lower limit of what commercial continuous emission 

monitors (CEMS) can reliably measure, if not below the level at which performance 

guarantees will be provided by vendors. Typical commercial CEMS can reliably

measure mercury concentrations in the range of 0.5 – 1 microgram per dry normal cubic 

meter (corrected to 3% O2). At concentrations below this level, the measurements 

become less accurate. Figure 1 shows mercury concentration in units of pounds per 

million Btu of heat input (x-axis), and converts that concentration to the units typically 

measured by CEMS (microgram per dry normal cubic meter, corrected to 3% O2).

- Figure 1 indicates that the emission limit proposed for new or reconstructed boilers 
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EO12866 Interagency Review. Subject to Further Policy Review.

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Figure 1 – Mercury Emissions by Coal Type1

(8.0 x 10-7Lb/mmBtu heat input) may be at, or below, the limit at which commercial CEMS can 

accurately measure. The Hg emission limit for new or reconstructed boilers (8.0 x 10-7

Lb/mmBtu heat input) will require activated carbon injection to achieve compliance. The 

mercury research and development program conducted by DOE concluded that, at best, 80-90% 

continuous Hg removal was possible. Due to the varying mercury content of coal, compliance 

may not be achievable with some coals.

Figure 2 shows the mercury content of various domestic coal ranks. Any coal type that has a 

mercury content of greater than 8 Lb Hg/trillion Btu will require greater than 90% removal, 

which could effectively eliminate those coal types as a fuel source for new and reconstructed 

coal-fired boilers. 

The Methodology for MACT Floor Analysis released in December 2011 with the Proposed 

Reconsidered Rule appears to only set aside units that have process-specific fuels (i.e. fuels not 

readily available to other entities), and it does not construct a calculation that holds open the 

option for any U.S. source of coal to be used by a new or reconstructed coal-fired boiler. It is 

therefore recommended that this MACT limit for Hg emissions be reconsidered, taking into 

account both the varying mercury content of coal, and the removal capability of the 

compliance technologies that are available.

 

2

“Mercury in U.S. Coal – Abundance, Distribution, and Modes of Occurrence,” Tewalt, Bragg, and Finkelman; 

http://pubs.usgs.gov/fs/fs095-01/

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.30E-07 7.30E-07 1.23E-06 1.73E-06 2.23E-06 2.73E-06

microgram/dry normal cubic meter (3%

O2)

Lb Hg/mmBtu

Appalachian Bituminous

Interior Bituminous

Western Bituminous

Western Subbituminous

Fort Union Lignite

Gulf Coast Lignite

1 microgram/dry normal cubic meter (3% O2)

0.5 microgram/dry normal 

cubic meter (3% O2)

8.0 x 10-7Lb Hg/mmBtu
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Figure 2 – Mercury Content by Coal Type2

Energy Efficiency Provisions

1. Sec. 63.7575 amendment of (b) definitions -- Pg 296, Efficiency credit 

definition. 

 Commenters are concerned by the removal of the text “Shutdowns cannot be used to 

generate credits.” Shutting down a boiler is not an efficiency measure or activity. 

Qualifying shutdowns as efficiency is an inadvisable policy precedent.

 To remedy, commenters strongly recommend EPA reconcile the language on pg 296 with 

the language on pg 232 (Sec. 63.7533 Can I use efficiency credits earned from 

implementation of energy conservation measures to comply with this subpart?) that states 

efficiency credits cannot be generated by boiler shutdowns unless the shutdown comes 

from energy savings that resulted from implementing the energy assessment measures. In 

addition, commenters recommend that EPA add in language on both page 296 and page 

232 requiring that such a facility provide supporting documentation linking the shutdown 

to energy conservation measures identified in the energy assessments.

 

2

“Mercury in U.S. Coal – Abundance, Distribution, and Modes of Occurrence,” Tewalt, Bragg, and Finkelman; 

http://pubs.usgs.gov/fs/fs095-01/
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2. Pg 298 – Energy management definition, page 47 (IV. Summary of Significant Changes 

Since Proposal, G. Energy Assessment), and page 365-67 (Table 3 to subpart DDDDD of 

part 63). 

 A commenter is concerned with the change to allow a facility that has an energy

management program to satisfy the energy assessment requirement. Having an energy

management program does not mean that all savings have been identified, and the 

commenter believes there is value in requiring all affected sources to have an energy 

assessment as the May 2012 rule did. Traditional energy management programs and 

measures can lack persistence because they stand alone. The commenter recommends 

striking the new language since May 2012 that would relieve a facility from actually 

performing an energy assessment.

 A commenter is concerned with edits to the definition of “energy management program” 

that added specific reference to ”ENERGY STAR guideline for energy management, 

DOE Save Energy Now, or ISO 50001 compatible energy management systems.” The list 

of items that must be included in the energy assessment is most important, and while 

federal government programs change over time, they will include these items. A 

commenter recommends striking reference to the voluntary standards in the 

definition and adding a sentence that refers to ISO 50001 only:

“Energy management program means a program according to the ENERGY 

STAR guideline for energy management, DOE Save Energy Now, or ISO 50001 

compatible energy management systems that includes a set of practices and 

procedures designed to manage energy use that are demonstrated by the facility’s 

energy policies, a facility energy manager and other staffing responsibilities, 

energy performance measurement and tracking methods, an energy saving goal, 

action plans, operating procedures, internal reporting requirements, and periodic 

review intervals used at the facility. Facilities may establish their program 

through energy management systems compatible with ISO 50001.

 If EPA does not strike the edit, for accuracy purposes, replace “Save Energy Now 

program” with “Superior Energy Performance.”

3. Pg 46 - IV. Summary of Significant Changes Since Proposal, G. Energy Assessment

 A commenter is concerned with the introduction of a maximum limit of “160 

technical hours” for an energy assessment. DOE’s energy savings assessments 

typically are 24 hours in length. Adding a maximum limit to the regulation is not 

necessary, and setting one that is dramatically higher than typical assessments could 

signal an expectation that initial energy assessments could create situations where 

facilities pay higher costs to meet the regulatory requirement due to private sector 

companies artificially inflating their time. 
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4. Pg 48 - IV. Summary of Significant Changes Since Proposal, G. Energy Assessment, page 

311 (§63.7575 What definitions apply to this subpart?), page 365-67 (Table 3 to Subpart 

DDDDD of Part 63—Work Practice Standards)

 A commenter is concerned that EPA has weakened the definition of “qualified 

energy assessor.” A commenter recommends that EPA restore the qualifications 

included in the May 2012 reconsidered proposal. The May 2012 definition (see 

below) would assure a minimum level of assessor expertise that the facilities will 

receive when they comply with the rule.

 Basis for concern: The revised text makes the definition more general so that an 

assessor is only required to have knowledge and capabilities specific to the processes 

at the site, and to clarify that qualified energy assessors may be company employees 

or outside specialists. In DOE’s experience with energy savings assessments, a thirdparty regularly finds savings that plant personnel do not. A worst case scenario would 

be with these changes, a facility could have their current plant manager do a plant 

walk-through / cursory inspection focused on the processes related to the regulation 

and make a determination that the plant has no additional opportunities for energy

savings. This doesn’t seem to meet EPA’s stated intent in including this requirement 

in the regulation.

 In addition, by removing the specific demonstrated qualifications and expertise, 

facilities may not be receiving sufficiently robust assessments from qualified experts 

that can identify additional savings. 

 For reference, below are the new proposed definition and the May 2012 

definition:

 NEW EPA LANGUAGE: Qualified energy assessor means a person 

or persons who have demonstrated capabilities to evaluate energy

savings opportunities for steam generation, process heat, and major 

steam and process heat using systems, as applicable to the facility. 

Qualified energy assessors may be company employees or outside 

specialists.

 MAY 2012 LANGUAGE: Qualified energy assessor means:

(1) Someone who has demonstrated capabilities to evaluate

energy savings opportunities for steam generation and major

energy using systems, including, but not limited to:

(i) Boiler combustion management.

(ii) Boiler thermal energy recovery, including

(A) Conventional feed water economizer,

(B) Conventional combustion air preheater, and
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(C) Condensing economizer.

(iii) Boiler blowdown thermal energy recovery.

(iv) Primary energy resource selection, including

(A) Fuel (primary energy source) switching, and

(B) Applied steam energy versus direct-fired energy versus

electricity.

(v) Insulation issues.

(vi) Steam trap and steam leak management.

(vi) Condensate recovery.

(viii) Steam end-use management. 

(2) Capabilities and knowledge includes, but is not limited

to:

(i) Background, experience, and recognized abilities to

perform the assessment activities, data analysis, and report

preparation.

(ii) Familiarity with operating and maintenance practices

for steam or process heating systems.

(iii) Additional potential steam system improvement

opportunities including improving steam turbine operations and

reducing steam demand.

(iv) Additional process heating system opportunities

including effective utilization of waste heat and use of proper

process heating methods.

(v) Boiler-steam turbine cogeneration systems.

(vi) Industry specific steam end-use systems.

Editorial Issues and Clarifications:

- Page 19, Table 3: Please revise the mercury emission limits in this table, as the 

information provided for most sources is not complete.

- In Table 3 of the preamble (section III. C.) all of the mercury limits and a couple of the 

HCl limits are missing the latter portion of the scientific notation. All values in this table 

should match the values in Tables 1 and 2 to Subpart DDDDD.

- In Section III. D. of the preamble at the bottom of page 24, change the following text to 

read as follows to be consistent with the changes already made the identical text in Table 
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5 of the rule. “...If you are firing a fuel other than natural gas, refinery gas, other gas 1 

fuel, or light liquid fuels, you must engage all of the applicable control technologies 

except dry scrubber, fabric filter, and SCR during periods of startup and shutdown. You 

must start your dry scrubber, fabric filter, and SCR systems, if present, appropriately to 

comply with relevant standards applicable during normal operation. You must comply 

with all applicable emissions and operating limits at all times the unit is in operation 

except for periods that meet the definitions of startup and shutdown in this subpart. You 

must keep records during periods of startup or shutdown. You must maintain records 

concerning activities and periods of startup or shutdown, as specified in § 63.7555.”

- Area source rule refers to "oxygen trim systems" and the major source rule refers to both 

"oxygen trim systems" and "continuous oxygen and CO trim systems." If these all refer 

to the same systems perhaps the language should be consistent within and between both 

rules.

- Footnote “a" in Tables 1, 2, 11, 12, 13 says “at or 75 percent of” which should probably

be “at or below 75 percent of” per 63.7515(b).

- Table 3 item 3 says all large units (10 MMBtu or greater) are subject to an annual tuneup. 63.7540(a)(10) says large gas 1 and MPF units are subject to an annual tune-up but 

does not indicate a tune-up requirement for large units in other categories. 63.7540(a)(10) 

does say this annual frequency does not apply to limited use units and units with trim 

systems which is true but seems to conflict with Table 3 item 3. 63.7540(a)(10) and Table 

3 item 3 might both need clarification.

-