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Chapter 10

Issues for which EPA Requested Comments

Contents

10.1 General............................................................................................................................................. 2

10.2 Not Proposing Separate N2O or CH4 Emission Limits.................................................................... 4

10.3 Gross vs. Net Output Based Standards............................................................................................ 6
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10.1 GENERAL

Comment 10.1-1: One commenter (10098) stated that while alternative proposals may have benefit in 

some rulemakings by allowing commenters to weigh the pros and cons of various rulemaking options, it 

is counterproductive in the context of an NSPS rulemaking. Under NSPS, EPA takes the position that a 

standard becomes effective at the time of proposal, meaning that any fossil-fuel-fired EGU commencing 

construction after January 8, 2014 could be subject to whatever final standard EPA selects. However, 

given all of the competing provisions in the proposal, it is impossible for such a facility to know what 

the final standard will be.

Response 10.1-1: EPA sympathizes with this comment, although EPA notes that the final standard of 

performance for fossil-fired steam electric units is quite similar to that proposed: BSER remains partial 

CCS, and there are alternative compliance pathways encompassed by the proposal (e.g. IGCC). 

Comment 10.1-2: One commenter (10664) stated that they appreciate EPA's interest in the potential for 

beneficial reuse technologies and its solicitation of comments on how the proposed performance 

standard may be revised to support the development and ultimate commercial deployment of such 

technologies. At the same time, however, EPA proposes to prohibit any technological system of 

continuous emission reduction ("technology") other than geologic sequestration to meet the proposed 

performance standard, until it approves alternatives for use. Such prohibition offers so much uncertainty

and risk to effectively eliminate any incentive to innovate. If adopted, it would have an intense stifling 

effect on the further development and ultimate commercial deployment of algae-based technologies, 

solar fuel technologies, and possibly other beneficial CO2 reuse technologies.

Response 10.1-2: Partly in response to this and similar comments, the final rule establishes a case-bycase mechanism under which EPA may approve alternative storage methodologies demonstrated to be 

of equal efficacy to sequestration.

Comment 10.1-3: One commenter (10681) stated that EPA asked for comments on the use of the 1/3 

output sales criteria versus a criteria between 20 and 40%. The commenter stated that the original 1/3 

criterion in the Part 75 rule was not derived from rigorous analysis. However there is significant value 

from using the Part 75 criterion in this rule for consistency between the two sets of requirements. While 

there might be technical and design grounds to change this percentage for CO2, the resulting confusion 

and additional workload on the sources and the regulators may not be worth changing this aspect of rule 

applicability. The commenter suggests that it may be preferable to establish a different criteria, such as 

permitted hours of operation or design LHV heat input rate instead of using the 1/3 sales and 219,000 

MWh criteria as part of the applicability test to define what might be a simple cycle combustion turbine.

Response 10.1-3: As explained in Sections IX.A and B of the preamble to the final rule, the EPA 

finalized a version of the broad applicability approach where the percentage electric sales criterion is 

used to distinguish two subcategories of natural gas-fired combustion turbines. We abandoned the 

proposed one-third electric sales threshold in favor of the sliding scale, which is based on a turbine’s 

LHV design efficiency rating. We also abandoned the 219,000 MWh aspect of the total electric sales 

criterion for non-CHP combustion turbines.

Comment 10.1-4: One commenter (10619) stated that EPA requested comment on a range of 950-1,100 

lb CO2/MWh for new stationary combustion turbines with a heat input rating greater than 850 

MMBtu/h. The commenter believes the use of a 1,000 lb CO2/MWh standard would be an acceptable 
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standard. The combined cycle natural gas units built in Oklahoma since 1999, with a capacity factor of 

greater than .33, are able to meet this standard.

Response 10.1-4: The EPA is in fact adopting a standard of performance of 1000 lb. CO2/MWh.

Comment 10.1-5: One commenter (10619) stated that EPA requests comments to provide for an 

alternative method to calculate compliance on an annual period. Using a calendar year period simplifies 

the execution or enablement of any trading program.

Response 10.1-5: The EPA has concluded that a 12-operating month rolling average is appropriate. This 

approach assures that sufficient data is available for a representative emission rate. An annual standard 

would not necessarily include 12 operating months. The EPA notes that trading programs have separate 

goals than the 111(b) emission standards.

Comment 10.1-6: One commenter (10619) stated that EPA requested comment on whether to provide 

an explicit exclusion for simple cycle combustion turbines. Efficiency and economic concerns should 

govern which units are used for greater than one third of their capacity. Providing an explicit exclusion 

for simple cycle units in addition to the one third capacity factor would not provide an incentive to limit 

the use of a higher emitting unit when the grid is not in peak load condition. Therefore, the commenter 

does not believe EPA should provide an explicit exclusion for simple cycle units.

Response 10.1-6: We agree with the commenter and are not finalizing an exclusion for simple cycle 

combustion turbines. Instead, we are finalizing a subcategory for non-base load natural gas-fired units, 

the majority of which will be simple cycle turbines. The BSER for this subcategory is clean fuels, and 

the final standard is 120 lb CO2/MMBtu, which can readily be achieved by simple cycle turbines. 

Comment 10.1-7: One commenter (10618) supports the position that emergency conditions do occur 

and may require that all available operable EGUs interconnected to the electrical grid supply power to 

the grid. Multiple commenters (8964, 8969, 8970, 8973, 8995, 9318, 9671, 9672, 9736, 10392, and 

10876) asked that electricity that is generated in response to a grid emergency declared by a regional 

transmission organization (RTO), independent system operator (ISO), or control area administrator be 

exempted from the amount that is used to determine net sales for EGU applicability.

Response 10.1-7: The system emergency exemption is included in this final rule. Electricity sold as 

result of a system emergency will not could toward the percentage electric sales criterion determining 

the applicability of the non-base load and base load subcategories.

Comment 10.1-8: Regarding the calculation of the number of daily violations within an averaging 

period, one commenter (10618) stated that they object to the automatic imposition of penalties for 

exceedances without some exercise of discretion. There may be valid reasons, such as sustained periods 

of extremely cold weather that would support the need for exercise of enforcement discretion in cases of 

small exceedances of the CO2 standards. These objections aside, AEP agrees that violations should not 

be "double counted."

Response 10.1-8: Specific monitoring and reporting requirements are specified in preamble section X. 

and in the Rule Language at Table 3 to Subpart TTTT of Part 60 - Applicability of Subpart A General 

Provisions to Subpart TTTT.

Comment 10.1-9: Regarding the appropriate method to recognize the environmental benefit of district 

energy systems, one commenter (9042) agrees that there may be environmental benefit to a district 
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energy system, particularly in comparison to multiple smaller heating and cooling systems. However, 

Colorado requests that EPA conduct a more thorough analysis of district energy systems before setting 

an emissions standard for these systems. Commenter (10681) stated that the determination of the useful 

energy actually used should be done through thermodynamic calculations that have been reviewed and 

approved or accepted by the permitting authority. Commenter (10554) stated that District Energy

System's emission rates should not be adjusted for thermal output. These systems are already realizing a 

reduction in the cost to comply with environmental controls and cost to operate, which is providing an 

added benefit. Therefore, they should be held to the same standard, if applicable, without an adjustment.

Response 10.1-9: This final rule does not include any special consideration for determining the useful 

thermal output from district energy systems for compliance purposes. The EPA notes that few district 

energy systems would meet the final electric sales applicability criteria.

10.2 NOT PROPOSING SEPARATE N2O OR CH4 EMISSION LIMITS

Comment 10.2-1: One commenter (10098) stated that EPA fails to address the inconsistency between 

the scope of the Section 202(a) endangerment finding, which included CO2, nitrous oxide, and other 

GHGs, and the proposed rule here, which only applies to CO2. While EPA suggests that the emissions of 

nitrous oxide and methane from the new source category are insignificant, it fails to address the fact that 

these emissions played an important role in EPA's endangerment determination under Section 202(a).

One commenter (5605) stated these other GHGs 100-year global warming potential is 21 to 310 times 

greater than that of carbon dioxide. Measuring these byproduct gases is essential and could be beneficial 

for regulatory purposes, as well as the means of potentially urging for aggregating those gases for fuels 

for existing vehicles and mechanisms able to utilize the combustion of the gases in a cleanly manner.

Response 10.2-1: EPA has insufficient information on CH4 and N2O emissions from this sector to 

develop standards of performance for these pollutants at this time.

Comment 10.2-2: One commenter (10045) stated that EPA proposed to set standards only for emissions 

of CO2 and, hence, not to set standards for the five other GHGs for which they made the 2009 

Endangerment/Contribution Findings. EPA based that proposal solely on the ground that emissions of 

those other GHGs represent less than 1 percent of total estimated GHG emissions from fossil fuel-fired 

EGUs and, evidently regulation of emissions of those other GHGs would yield a gain of trivial or no 

value, yet impose significant cost burdens.

Response 10.2-2: EPA has insufficient information on CH4 and N2O emissions from this sector to 

develop standards of performance for these pollutants at this time. EPA notes further, however, that 

these pollutants would be considered and addressed on a source-by-source basis as part of the PSD 

permitting process, so that each new source would have an individual permit limit based on BACT for 

both CH4 and N2O. Indeed, these pollutants have been addressed in various PSD permits issued by EPA 

and states to date.

Comment 10.2-3: Multiple commenters (8939; 9678, 9425, 8952, 8957, 9426, 9471, 9591, 9593, 

10095, 9666, 10048; 10102; 10242; 10554; 10606; 10618; 9661) supported EPA's decision to regulate 

only CO2 emissions.

One commenter (9678) stated that current best practices are most appropriate for minimizing non-CO2

GHGs emissions, and would not support collecting emissions information under this rulemaking. Given 
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the magnitude of the current effort, including upcoming existing source regulations, the commenter 

supports EPA's focus on CO2.

One commenter (9425) stated that they agree that EPA should not propose separate CH4 or N2O

emission limits although nitrous oxide (N2O) (and to a lesser extent, methane (CH4)) may be emitted 

from fossil fuel-fired EGUs, representing only about 0.4 percent of total CO2 equivalent emissions from 

fossil fuel-fired electric power generating units.

Several commenters (9425; 9426; 10048; 10095; 10102; 10618) stated that they agree with EPA's 

decision to focus on CO2 and not focus its efforts at this time nor burden compliance entities with this 

small fraction of emissions. In general, the N2O and CH4 emitted at any of the commenter's facilities 

makes up approximately one percent or less of that facility's total GHGs. The commenter (10102) 

provided a table of percentage of total GHG emissions from N2O and CH4 from the commenter's power 

plants.

One commenter (8957) stated that they believe that EPA's rationale to focus on CO2 as opposed to CO2e 

appears to be well founded citing other data from EIA and AP-42 emission factors that indicate that the 

other GHG are a small percentage of total GHG.

One commenter (9471) stated that because the costs of monitoring and reporting these de minimis 

emissions would outweigh any marginal benefits that might result from regulation they support EPA's 

proposed action.

One commenter (9591) stated that to the extent that non-CO2 emissions are included in a PSD permit, 

limits are set using emissions factors and controlled through best practices. Therefore, establishing an 

NSPS is not appropriate at this time.

One commenter (10095) stated that CO2 is the primary GHG emitted from a fossil fuel fired EGU. 

One commenter (9666) stated that there is no basis or reason to set standards for nitrous oxide or 

methane. Valid or accurate data for methane and N2O emissions are lacking. The commenter stated that 

the costs that would be imposed on sources to monitor and report these emissions would far outweigh 

any negligible benefits that might accrue from any emission limits for these substances under section 

111. 

One commenter (9666) stated that they support EPA's proposed decision and does not believe that EGUs 

equipped with SCR produce much, if any, N2O, and new EGUs will likely have such equipment to meet 

NOx NSPS. 

One commenter (9666) stated that the costs to monitor and report these emissions far outweigh any 

negligible benefits that might accrue from any emission limits for these substances under section 111. 

One commenter (9593) stated the emissions of N2O and CH4 from power generation are de minimis 

compared to emissions of CO2. For example the commenter has found - and EPA's Emissions & 

Generation Resource Integrated Database (eGRID) confirms - that power plant emissions of N2O and 

CH4 per MWh are approximately six orders of magnitude smaller than per MWh emissions of CO2. 

Even after accounting for the higher global warming potential of these gases, their CO2 equivalent 

emissions are approximately one half of one percent of the CO2 emissions. One commenter (10618-

3395) stated that because existing EGUs have been calculating and reporting N2O and CH4 emissions 

under the GHG Reporting Rule since 2011, using emissions factors, additional measurement and 

reporting is not justified.
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Response 10.2-3: The final rule only includes standards for emissions of CO2. The issue is discussed in 

Section III.G. of the preamble to this final rule.

Comment 10.2-4: One commenter (9666) stated that they do not know the basis for EPA's statement in 

the preamble that units equipped with SCR equipment generate N2O. EPRI's work on a pilot-scale SCR 

program, confirmed by tests in Europe, led to its conclusion that "N2O was not being formed across the 

vanadia/titania catalyst." 

Response 10.2-4: Since N2O is not being regulated in this final rule the comment is not relevant.

10.3 GROSS VS. NET OUTPUT BASED STANDARDS

Comment 10.3-1: One commenter (10098) stated that EPA requested comments on alternative 

proposals, which created uncertainty and confusion regarding EPA's intentions for the final standard. 

Examples include: 

EPA requests comment on three competing definitions of "gross energy output," 79 Fed. Reg. at 1447;

EPA requests comment on whether it should apply a gross-output based standard or a net-output based 

standard.

Response 10.3-1: See preamble section III.F.1.

Comment 10.3-2: Several commenters (7990; 8937; 9194; 9425; 9426; 9592; 9597; 9661; 9665; 9666; 

9780; 10023; 10031; 10100; 10500; 10520; 10554; 9396) stated that they support gross output-based 

standards. The commenters does not believe that a net basis standard is appropriate in this context. 

Pollution control technology, including the use of CCS, often imposes significant parasitic load 

requirements on an EGU. If EPA were to adopt a standard that was calculated on a net basis, that level 

would need to be even higher to account for parasitic load. However, given the potential range of control 

options and corresponding parasitic load requirements, arriving at such a standard is impractical and 

would not further the objective of the Proposal. A gross output-based standard also is consistent with the 

monitoring requirements under Part 75, and with other programs, such as the Acid Rain Program, which 

already relies on gross megawatt data. If EPA adopts a standard based on net output, then that standard 

needs to be even higher to account for the parasitic load. Net output-based standards, if included in any

final rule, should be included only as an optional alternative to gross output-based standards. The gross 

methodology does not factor into the emissions rate added parasitic loads from emissions control 

retrofits, which may avoid future NSPS modification issues with such retrofits.

One commenter (9425) stated that net output is often simply an indicator of the level of environmental 

controls at a facility. A net power approach would drastically increase the stringency of the proposed 

1,000 lb/MWh NSPS for CCS applications. The additional stringency is not warranted. 

Commenters (9425; 9426) stated that in the NSPS for Subpart Da conventional pollutants rulemaking, 

EPA agreed not to require a net output approach. EPA should remain consistent and use gross output 

when finalizing this rule. EPA justifies a net output standard as an alternative by saying that it would 

provide incentive to choose a more efficient EGU design, select fuels that require less emission controls, 

and recognize the environmental benefit of higher efficiency pumps motors and fans. However, 

economic forces already provide utilities appropriate incentives to minimize all these factors. Therefore, 

gross generation is a sufficient indicator of compliance with environmental standards.
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One commenter (9665) supports gross output-based standards and stated that the proposed use of 

periodic fuel sampling as an acceptable monitoring method provides appropriate compliance assurance 

such that further requirements should not be imposed.

One commenter (9665) stated that if EPA adopts a partial CCS standard, it should be no more stringent 

than the proposed standard of 1,100 lb. CO 2 /MWh and must be on a gross output basis.

EPA has proposed that "the level of partial capture of CO2 that qualifies as the BSER supports a 

standard of 1,100 lb CO2/MWh on a gross basis. This standard is based on an emission level achievable 

with a single-stage, water-gas shift (WGS) reactor and a two-stage acid gas removal system. EPA also 

solicited comment on the achievability of standards ranging between 1,000 and 1,200 lb CO2/MWhgross, and whether EPA should adopt what amounts to an adjusted gross energy output standard or 

alternatively a net-output based standard.

The commenter stated that EPA would be better served to adopt an emission limit achievable by stateof-the-art IGCC and other highly efficient technologies without CCS. However, if EPA moves forward 

with a partial CCS-based standard, then the commenter recommends that EPA finalize its proposed 

output-based standard. The commenter does not dispute EPA's conclusion that a new IGCC EGU 

configured with a single-stage WGS reactor and a two-stage acid gas removal system should be able to 

achieve a gross output standard of 1,100 lb CO2/MWh on a 12-month rolling basis. However, the 

commenter does not support an adjusted gross energy output or net-output based limit.

One commenter (9665) stated that they support a gross output-based standard for subpart Da and subpart 

KKKK sources (and for Subpart TTTT if that option is finalized). The commenter does not support net 

output-based standards. In general, determining the net output of an EGU is complicated and prone to 

errors. Although complications may be less for traditional coal- fired sources versus IGCC units, the 

commenter supports the use of gross output standards for all sources provided that all parasitic loads and 

auxiliary equipment are accounted for when determining the gross output of the unit. EPA should revise 

the definition of IGCC to clarify that the entirety of the unit is assessed in accounting for the gross 

electricity output of such units. EPA should finalize its proposed definition of "gross energy output."

Regarding EPA's suggestion that net output-based standards might remove an incentive to power 

feedwater pumps by electricity instead of steam (since using electricity for this activity would not act to 

raise the CO2 emissions calculated for a source under a gross output-based standard), one commenter 

(9665) stated that even assuming that such incentive exists, the benefit of switching to net output-based 

standards would be small and would not justify the substantial complexities in both defining and 

implementing such a standard at affected sources.

Regarding EPA's position that net output supplied to the end user could be considered a "better 

indicator" of the environmental performance of a unit than gross output one commenter (9665) stated 

that this observation ignores the substantial economic incentives that all electricity providers have to 

generate electricity efficiently. Especially within deregulated electricity markets, an electricity provider 

has no incentive to use more fossil fuel to produce the same amount of electricity as a competitor. The 

commenter also agrees with EPA's assessment that it lacks sufficient data to establish a net output-based 

standard since continuous emission monitoring system (CEMS) emission data are reported on a gross 

output basis pursuant to 40 CFR Part 75.

One commenter (9427) stated that using gross MWH criteria for determining applicability of the 

standard to a stationary combustion turbine is warranted because: 
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-Gross MWH applicability criteria places the entire focus on the combustion turbine, not on sales 

to the utility distribution/transmission system (the "electric grid"), and not on station service 

energy that may or not be directly relevant to the combustion turbine. 

-Gross MWH applicability criteria would be based on the same measurement location as for 

compliance, that is, the combustion turbine's electric output terminals where watt meters would 

be installed as required by proposed rule section 60.4373(d). 

-Gross MWH applicability criteria would appear to match the intent of the example in the 

proposed "potential electric output" definition, which refers to a "35% efficient stationary

combustion turbine" (the efficiency of the turbine itself, not efficiency based on sales to the 

electric grid). 

Commenter (8957, 10098) stated that they believes that a gross output-based standard is more 

appropriate than the net output-based standard because the units controlled by scrubbers and selective 

catalytic reduction devices would consume more energy than from uncontrolled units. The definition of 

gross output should allow for 100% of the useful thermal energy being produced and used to be 

included, as opposed to the 75% credit being proposed. To fully account for the climate benefits of CHP 

and to reflect the Administrations' efforts to promote CHP, EPA must count 100% of the useful thermal 

energy. Such an approach is also consistent with the past practice of EPA and the states.

One commenter (9591) stated that they support an output-based because it does not penalize a facility

for employing pollution control systems that consume electricity, such as scrubbers or SCR. The use of 

gross output aligns this rule with recent EPA rulemakings, including the Mercury and Air Toxics 

Standards (MATS). According to the commenter, if EPA were to finalize a net-output based standard or 

include an optional net-output based standard, it would be important for EPA to clarify the definition of 

net electric output for the purposes of calculating the emission rate. EPA's proposed definition under 

KKKK for non-CHP units is "[t]he gross electric sales to the utility power distribution system minus 

purchased power on a 3 calendar year rolling average basis". However, there could be cases when an 

operator would purchase power to satisfy contractual requirements that would not reduce gross electric 

sales from the unit. If that is the case, the current definition would reduce the MWh in the denominator 

while the emissions in the numerator are unchanged, effectively tightening the standard.

Two commenters (9426; 10095) stated that gross output-based standards are the simplest to measure and 

for the CO2 emission rate calculation for compliance purposes rather than an unduly complex net output 

calculation. The use of gross output allows the plant operator to account for electrical, mechanical, and 

thermal energy use by the plant, giving operators the needed flexibility to design systems in the most 

efficient and economic manner.

Commenter (9661) stated that the calculation of compliance using the annual average basis for a 

calendar year is much simpler to administer, is less costly and, based on our analysis, provides the same 

guarantee that the environmental standard will be achieved. EPA should allow the option of conducting 

a calendar year average (sum of the emissions for all annual (calendar year) operating hours and to 

divide that value by the sum of the annual [gross] electrical energy output and useful thermal energy

output).

One commenter (10095) stated that gross MWh output is straightforward, simple, consistent, directly

measured, and already reported to EPA for other purposes as required by 40 C.F.R. part 75. 

Furthermore, market drivers will continue to ensure that power producers operate efficiently because 

utilities have a strong incentive to ensure the gap between gross and net output is as small as possible, 
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maximizing the return on investment. By recognizing that a generating unit's gross energy output is 

comprised of electrical, mechanical, and thermal energy uses, EPA avoids creating an incentive for 

utilities to power station equipment with electricity rather than steam. If EPA had focused solely on the 

electrical component of gross output, the generation of more electricity to serve the plant's equipment 

would result in a lower lb/MWh calculation than if the equipment were powered by steam, even though 

the use of electricity could be less efficient in some cases.

One commenter (10095) stated that a gross energy output standard that incorporates useful thermal 

energy would also encourage the use of waste heat produced during the energy conversion process or 

steam used throughout the CCS process. The commenter specifically supports EPA's acknowledgment 

that supplying steam for anime regeneration in a CCS system is categorized as "useful energy." By

allowing for the incorporation of waste heat and steam as a compliance option (increased gross MWh 

output with no additional CO2 emissions), a gross output-based standard that recognizes electrical, 

mechanical, and thermal energy uses would allow operators to respond to market drivers and make 

choices with respect to the quality of the waste heat and steam they produce, increasing the overall 

utilization of the energy.

One commenter (10095) stated that net MWh output is facility-specific and difficult to accurately 

calculate. For example, many facilities have transformers that support multiple units at the facility, 

making unit-level reporting difficult. More importantly, station electric services may come from other 

outside sources to supply lighting, well pumps, and other ancillary loads. Additionally, some station 

services are dedicated per unit, while other station services may be measured at a facility level. 

Examples of facility-wide equipment that often serve more than one unit include coal handling 

equipment such as unloaders and conveyors, electric fire pumps, cooling tower makeup pumps, and 

pollution control equipment (e.g., FGD and baghouses). Accurately measuring and reporting all of these 

sources would require complex calculations and would naturally lead to variations among affected 

sources and inconsistencies in both reporting CO2 emission rates and complying with the proposed CO2

standard. A net output-based standard would also discourage the deployment of technologies that could 

successfully reduce CO2 emissions at a lower cost, such as combined heat and power ("CHP") and cogeneration.

One commenter (9666) stated that nothing has changed from February 2012 that would now make a net 

generation-based emission rate appropriate and achievable Parasitic power demands at NGCC plants 

would be much less than at coal-fired EGUs with CCS. The Agency's suggested conversion from gross 

to net NSPS may not properly take into account all of the variables such as base-load versus cycling 

operation. The commenter has no objection to the inclusion of an optional net output-based standard that 

may appeal to some owners or operators of NGCC units. 

One commenter (9666) stated that they disagree with EPA's statement that a net-output based standard 

"would provide more operational flexibility and expand the technology options available to comply with 

the standard for coal-fired PC and CFB EGUs." The commenter has found no explanation in the 

preamble or the record as to why the Agency believes such operational flexibility might occur. As 

discussed elsewhere, the commenter doubts that any coal-fired units will be planned or built if CCS 

continues to be required, so this issue is theoretical and moot.

One commenter (10554) stated that they support a gross output basis because using a net-output-based 

standard could create a perverse incentive to provide auxiliary loads from the grid or to supply ancillary

support services (natural gas compression, circulating water supply, etc.) from off site to reduce the 

emission limit. This could actually increase CO2 emissions by not using the most efficient method of 

providing these services. 
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One commenter (3862) supports the optional use of net energy or gross energy output. Since the current 

Part 75 Acid Rain rule specifies gross output, it may be preferable for us to continue using gross energy, 

but less preferable for a coal fired facility seeking greater operating flexibility. The 75% credit for onsite 

steam should be evaluated for use of a higher value vs. a lower value as suggested. EPA should reiterate 

the basis for this value as it is used in the calculations of gross energy output for combustion turbines.

One commenter (10136), on EPA's request for input on calculation of gross output and whether the 

Agency should instead express emissions on a net output basis, stated that the Agency should utilize the 

system that best and most transparently reflects the "costs" -- carbon costs, criteria pollutant costs, and 

costs in extra fuel burned -- of putting a megawatt-hour of electricity on the grid. Compatibility and 

transferability between calculations used to estimate greenhouse gas emissions and conventional 

pollutants should be emphasized, as well, to promote the simplest and most information-rich system for 

evaluating costs.

One commenter (3175) stated that for affected units with a heat input of less than or equal to 850 

MMbtu/h, they support basing the emissions rate on the gross output of the gas turbine as measured at 

the generator terminals as opposed to the net output taking into account parasitic loads. We are confident 

that plant owners will always select the most efficient auxiliary systems, but variations in site 

conditions, available gas pressure, available cooling water sources, etc. will likely penalize some owners 

and benefit others simply through variations in their particular plant site conditions if a net basis is used 

with negligible overall effect, but potentially significant effect for certain operators. We feel taking these 

variations off the table will simplify measurement and enforcement with negligible overall effect.

One commenter (10618) stated that EPA should be consistent in the use of gross-based output standards 

in this rulemaking. Generally, the commenter supports the use of gross output-based standards, however, 

the use of gross-based generation results in a number of complex technical and operational 

considerations that can influence emission rates and unit efficiencies. These issues warrant a much 

greater technical analysis, which further supports that finalization of these standards is premature and 

that the proposed rule should be changed to an advanced notice of proposed rulemaking so that the 

agency can fully evaluate the implications and design of gross-based output standards.

Response 10.3-2: See preamble section III.F.1.

Comment 10.3-3: One commenter (9664) stated that they are seeking final subpart Da standards that 

are expressed on a net output basis, and as well in seeking more robust net emissions rate standards for 

subpart KKKK units.

One commenter (8952) stated that they support net output-based standards.

One commenter (9650) stated that a standard utilizing "Net Output" allows more leeway and, should it 

continue to mandate CCS, EPA must adopt the proposed "net output based standards." 

One commenter (10466) stated that net output should be used as the basis for the standard, rather than 

gross output, to be consistent with State standards and to reduce the reporting/compliance burden on 

sources in States that have already implemented GHG standards.

One commenter (9201) stated that they support the use of net output-based approaches for all covered 

sources, as the utilization of those approaches more accurately captures advances in boiler efficiencies. 

EPA appears to only focus on applicability to units with CCS controls, despite the general recognition 

that net output-based approaches account for advances in process efficiencies on a much broader scale. 
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Net output-based approaches are particularly appropriate to advance emission reductions from base load 

sources at either units with or without CCS technology, and as such should be adopted as an option for 

those sources at a minimum. 

One commenter (9514) stated that the final rule must promote more efficient designs of all coal- and 

gas-fired facilities, including those provided by setting the standard on a net-output basis for all affected 

facilities. 

Commenters (9514; 10038; 10682) stated that one stated objective of EPA's proposal is to encourage the 

development and use of more efficient generation. The proposed gross-output based standard actually

discourages this result by ignoring the amount of electricity that the facility uses before it sells the 

electricity to the grid. A gross-output based standard merely tracks the total amount of electricity 

generated per unit of pollutant emitted. By contrast, under a net-output based standard, compliance is 

determined based on the amount of electricity made available to the grid per unit of pollutant emitted.

Commenters (9514, 10619) stated that a net-based standard better promotes "technology forcing" 

throughout the industry by encouraging the selection of more efficient electric generating unit designs. It 

also provides incentives over the long run for further research and development of even more energy

efficient control processes and equipment.

One commenter (9514) stated that EPA is misguided to argue that a gross-output standard is needed to 

accomplish "technology forcing;" in fact the opposite is true - a net-output based standard better 

provides the necessary incentives to move technology that incremental step forward towards not only

deeper reductions, but deeper reductions that can be achieved more efficiently. 

One commenter (9514) stated that current generation IGCC or ultra-supercritical (USC) plants are able 

to achieve emission rates of 1,600 lb CO2/MWh (net-output) using 100 percent coal without capture 

technology. Future development of an advanced ultra-supercritical plant (AUSC) is projected to lead to 

design emission rates of less than 1,500 lb CO2/MWh (net-output) but not without a regulatory driver. 

With a small percentage of natural gas co-firing or a solar preheating system, such units might well 

comply with EPA's proposed standard, but only if the associated emission limitation standard was set on 

a net output basis. However, these units' future compliance with EPA's proposed gross-output emission 

rate of 1,100 lb CO2/MWh could not be achieved because such non-CCS units would not have the large 

parasitic loads associated with CCS. Without that load their gross emission rates would be much closer 

to net emission rates and higher than the proposed limit. Thus, a net-output based standard would 

promote more flexibility to the facility in finding new, innovative ways to comply while still preventing 

substantial CO2 emissions. 

One commenter (9514) stated that a gross output standard also biases the future development of CCS, 

and other equal or better carbon dioxide control options, by providing an advantage to IGCC units over 

AUSC units with CCS. EPA has proposed to address this issue with a third unit of measurement - an 

"adjusted gross output" standard in which the electric load needed to power the additional IGCC 

equipment is subtracted from the gross load. Because IGCC units have a much higher ancillary load than 

AUSC units, if one discounts the emissions associated with this load, an IGCC unit would only have to 

capture 25 percent of the CO2 emissions from the unit to comply with the proposed standard while an 

AUSC unit would have to capture 40 percent. This would result in greater real world CO2 emissions 

from the IGCC unit and a cost advantage for IGCC/CCS units over AUSC/CCS units. There is no reason 

for EPA to create this distinction. Any advantages to IGCC/CCS units will be revealed, promoting the 

technology without the need for special treatment. Moreover, there is no need for a separate treatment 

regardless, as EPA should finalize standards on a net output basis for all units.
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Referring to Table 8 (Comparison of Net, Gross, and Adjusted Gross Emissions of Different Coal 

Configurations) of their submittal, one commenter (9514) stated the comparison highlights how EPA's 

proposed usage of a gross-output based standard may obscure the scope of the improvements that are 

potentially available from the proposed standard. By comparing gross emission rates (and ignoring the 

GHG emissions from the energy that it takes to operate CCS) EPA asserts that it estimates "this standard 

will result in reduction in emissions of at least 40 percent when compared to the expected emissions of a 

new SCPC boiler." While it is true that the actual CO2 emissions of a unit meeting EPA's proposed 

gross-output based standard would emit less CO2 than would a new, high efficiency SCPC unit, that 

reduction is closer to 15-20 percent when analyzed on a "pounds-of- CO2 "per unit-of-electricitydelivered-to-a-consumer" basis. In other words, the gross output standard overstates the real world 

impacts of the standard by at least factor of 2. 

One commenter (9514) recommended that EPA finalize an emission level of 1,200 lb CO2/MWh (netoutput), which EPA asserts is equivalent to 1,000 lb CO2/MWh (gross). There should not be a 

significant cost increase associated with a somewhat more stringent net emissions limit than proposed. 

Since, as described above, IGCC units without CCS have relatively high parasitic loads, setting the 

standard at the levels we suggest on a net-output basis would preclude compliance by IGCCs that co-fire 

relatively small percentages of natural gas. Because any IGCC/CCS unit would likely be a baseload unit, 

if fired on natural gas the CCGT portion of the IGCC would meet an emission limit of less than 850 lb 

CO2/MWh (net-output). For this reason, the flexibility of operation, by way of co-firing an IGCC with 

natural gas, which the agency seeks to promote can still be readily achieved at a lower level than 

proposed. Moreover, EPA's proposal would apply the Subpart KKKK standard to any IGCC that fires 

above a given percentage. If set at an appropriate level, this feature of the rule would preclude gaming of 

the partial CCS rule as EPA suggests.

Regarding the EPA suggestion that determining the net output of an IGCC facility could be "more 

challenging to implement, one commenter (9514) stated this would entail simply measuring the 

electricity associated with the primary gas compressors for electricity production - and EPA has not 

explained why this measurement would be "challenging." The agency's assertion simply does not 

support the proposed gross-output based emission standard for IGCC units, nor for subpart Da and 

KKKK units more generally. 

One commenter (9514) stated that they urge EPA to finalize rules that provide impetus for improving 

the efficiency of all generating technologies, including IGCC, through net-output based standards, 

because it is simply not the case that measuring net electric output poses too burdensome of a technical 

or financial challenge today - particularly for newly constructed units. It cannot be "more challenging" 

to require an operator to submit basic information for a new unit that it already gathers, apparently

without difficulty, for existing units. In fact, EPA has ready access to net metering data, and net 

electrical metering has become common in the industry for reasons set out by FirstEnergy fifteen years 

ago:

One commenter (9514) stated that EPA's preference for a gross output based standard because the 

agency only has CEMS emissions data reported on a gross output basis is inaccurate and largely 

irrelevant in setting standards for new coal-fired units with CCS. In this rulemaking, EPA is not setting 

an emission limit for either existing or new coal fired units without CCS. Part 75 data does not yet 

include emission data for CCS-equipped coal fired units and EPA does not rely on any Part 75 emission 

data in support of its proposed emission limit for new fossil-fuel fired steam EGUs. EPA bases the 

selection of the proposed level of capture in part on a policy preference to keep the levelized cost of 

electricity for new coal plants at or below that of new nuclear units and to allow development of a fossil 
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fuel-fired standard on an output basis. Thus, the fact that Part 75 data include gross electrical output is 

not relevant to a determination of the numerical emission limit associated with a BSER of partial CCS 

for fossil fuel-fired steam EGUs. 

One commenter (9514) stated that facilities calculate, and EPA has access to, emissions on a net output 

basis, which further demonstrates the Agency's flawed reasoning in further justifying a gross based 

standard based on a claim that it only has CEMS emissions data reported on a gross output basis. 

Facilities can easily calculate emissions data on a net-output basis as evidenced by the reports from the 

NETL, which includes detailed cost- and performance-analyses for new, state-of-the-art units with CCS 

providing both net and gross CO2 emission rates. Moreover, EPA has relied on this data, in part, to 

support its choice of BSER, indicating that it is aware that facilities calculate emissions data on a net 

output basis. In fact, EPA proposes to use net output data as a foundation of its rule. Although EPA 

proposes to establish the emission limitation on a gross-output basis, it also proposes that a source must 

determine whether it is an affected facility on the basis of the facility's net electrical output. This 

requirement further, and substantially, undercuts the agency's argument that determining net-output is 

too difficult to require of new sources subject to the regulation.

One commenter (9514) stated that even without a Part 75 requirement to do so, electricity generators are 

still currently required to report monthly gross and net generation data to EIA using EIA Form 923.290 

These data allow EPA to determine the net generation directly for many units and, for other units, to 

convert the gross generation reported for each unit in its data set to net generation. 

One commenter (9514) stated that additional data on the relationship between net and gross electric 

output of specific units and the achievable emission levels are available in permit files for new units 

seeking BACT determinations or PUC approvals. We note that in December of 2013, EPA Region IV 

issued a PSD permit for the reconstructed FPL Port Everglades facility that contained a 12-month limit 

of 830 lb CO2e/MWh on a net emissions basis. Clearly, a new facility has the ability to keep track of its 

emissions on a net-output basis. (Commenter provided links and attachments for example permitting 

documentation)

One commenter (9514) stated that they agree with the Agency that one of the key purposes of the 

proposed rule is to serve as a necessary "predicate for the regulation of existing sources within this 

source category under CAA section 111(d)." It is important to preserve the ability to encourage all 

available options to reduce emissions from EGUs, including efficiency improvements and reductions in 

parasitic loads. This is another extremely important reason to employ a true net-output standard.

One commenter (9514) stated that EPA should not allow sources an option to choose a net or gross 

output standard. As we point out above, a gross output standard fails to promote the agency's goal of 

encouraging the development of more and more efficient control options for carbon dioxide. Moreover, 

it also results in more real world CO2 emissions (per unit of electricity sold). Indeed, the fact that EPA is 

considering providing the option for facilities to choose demonstrates our point - that net-output 

standards are feasible. EPA has not provided any analysis in this proposal or the materials 

accompanying it of the additional emissions that might result from offering sources the opportunity to 

choose between net and gross output based standards.

Response 10.3-3: See preamble section III.F.1.

Comment 10.3-4: One commenter (8918) stated that EPA's logic is not clear for deducting the electric 

energy used to power boiler feed pumps from the definition of gross power output. Deducting the boiler 

feedwater pump's electric energy consumption is a step that would be involved in a net energy output 
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not a gross output. Furthermore, it appears that a facility with steam driven feedwater pumps would get 

to add, under (Pt)HR or (Pt)IE, the thermal energy in the steam used to drive the pump. Allowing the 

addition of steam energy to drive a boiler feedwater pump to the facility's gross energy output, while 

requiring the deduction of electric energy, double penalizes facilities with electric driven pumps. 

One commenter (9650) stated that EPA should define "gross energy output" for traditional and icc

facilities differently.

One commenter (9591) supports the proposal's revised definition of potential electric output, which 

would allow the source the option of calculating its potential electric output on the basis of actual design 

electric output efficiency, rather than a default of 33 percent. This proposed approach would avoid 

effectively penalizing more-efficient units.

Response 10.3-4: The gross electric output includes the energy used by electric feedwater pumps to 

avoid distorting the market. Feedwater pumps require large amounts of energy and can either be run by

steam or electricity. The energy used by steam powered feedwater pumps is not available to produce 

electricity and hence the gross efficiency is reduced. In contrast, the electricity to run feedwater pumps 

is after the measurement of gross electricity. Without this approach to measuring gross energy output, 

units with electric feedwater pumps would appear more efficient and have a lower output based 

emission rate. 

The definition of potential electric output in this final rule is based on either 33 percent or the design 

efficiency of the unit. For CHP units, design efficiency for purposes of calculating the potential electric 

output is at the maximum electric production rate. For example, a CHP unit with an extraction steam 

turbine that is capable of running at 100 percent condensing would determine the design efficiency for 

determining the potential electric output when only generating electricity. In contrast, a CHP unit 

without a steam condensing cycle would use the overall base load efficiency, including the useful 

thermal out, when determining the potential electric output. This approach satisfies one of our criteria 

for the industrial CHP exemption – exempting industrial units whose primary purpose is to provide 

useful thermal output.

Comment 10.3-5: One commenter (9665) stated that an adjusted gross energy output standard would be 

inappropriate for IGCC units. As EPA points out in the preamble, because IGCC facilities can produce 

by-products along with electricity, it would be "challenging" to measure electricity used by the primary

gas compressors associated with electricity production and hard to enforce. Thus, if EPA goes forward 

with a partial-CCS standard, it should finalize its proposal to define "gross electric output" for IGCC as 

"electricity measured at the generator terminals." The commenter stated that they also cannot support 

either a net-output based standard or a standard more stringent than 1,100 lb CO2/MWh given the 

uncertainty regarding whether such standards can in fact be achieved.

Response 10.3-5: The definition of gross output in this final rule does not subtract out the electricity

used by the gas compressors.

Comment 10.3-6: One commenter (7977) stated that the proposed rule improperly uses gross output as 

the basis for the standard and the proposed structure of regulatory applicability for co-generation units.

One commenter (10606) stated that EPA should adopt an optional standard that is expressed as a pound 

per MMBtu CO2 limit, in addition to a lb/MWh standard. This approach will simplify the process of 

applying the proposed lb/MWh standard to an integrated system where several boilers feed a common 

header, which feeds multiple electric generators and also provides steam to an industrial process. 
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However, the lb/MWh limit should also be retained in order to account for inherent inefficiencies in the 

system.

Response 10.3-6: The EPA notes that the lb/MWh standard includes 100 percent credit for useful 

thermal output. The definition of affected facility in this final rule does not include multiple boilers 

feeding a common steam header. In this case, each boiler would be a separate affected facility that 

would demonstrate compliance with the applicable emission standard separately.