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CHAPTER 2

CONTROL STRATEGIES 

2.1 Synopsis

This section defines the source categories affected by the proposal, outlines regulatory 

actions included in the analytical baseline, and describes the control strategies and regulatory 

alternatives for new, modified, reconstructed, and transitional sources. Existing EGU GHG 

sources are not addressed in this action, but will be the subject of a subsequent action by the 

EPA.

2.2 Definition of Affected Sources 

2.2.1 Electric Utility Generating Unit

For the purposes of this rule, the EPA is proposing to define an EGU as any fossil fuelfired combustion unit that has the potential to produce more than 25 MW electrical output and 

serves as a generator that produces electricity for sale, with the exception of simple cycle 

turbines. For this rule, the term EGU includes steam generating units (“boilers”), NGCC 

combustion turbines and their associated heat recovery steam generator (HRSG) and duct 

burners, and Integrated Gasification Combined Cycle (IGCC, "coal gasification") units – including 

their combustion turbines and associated HRSGs. A unit that cogenerates steam and electricity 

or that cogenerates feedstocks (e.g., hydrogen or hydrocarbons from an IGCC) for chemical or 

fuel production and supplies more than one-third of its potential electric output capacity and 

more than 25 MW output to any utility power distribution system for sale is also considered to 

be an EGU for the purposes of this rule. This rule does not cover simple cycle turbines.

2.2.2 New Sources

Sources affected by the new source provisions of the proposal are sources that are both 

considered “EGUs” and are considered “new” as defined by this rule. The general NSPS 

provisions (40 CFR Part 60) define a new source as one that begins construction (or 

reconstruction) after the date the provisions are proposed. 

CAA section 111(a)(2) defines a “new source” as “any stationary source, the 

construction or modification of which is commenced after publication of regulations (or, if 

early, proposed regulations) prescribing a standard of performance under [CAA section 111] 

which will be applicable to such source.” In contrast, CAA section 111(a)(6) defines an “existing 

source” as “any stationary source other than a new source.” The definition of a “new source” 

applies for purposes of this rulemaking, except that special considerations come into play for 
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sources undertaking physical or operational changes (modified sources), transitional sources, 

and sources undertaking reconstruction.

2.2.3 Modified Sources

The EPA does not have a sufficient base of information to develop a proposal for the 

relatively few affected sources that may take actions that would constitute “modifications,” as 

defined under the EPA’s NSPS regulations, and therefore be subject to requirements for new 

sources. A modification is any physical or operational change to a source that increases the 

amount of any air pollutant emitted by the source or results in the emission of any air pollutant 

not previously emitted. However, projects to install pollution controls required under other 

CAA provisions are specifically exempted from the definition of “modifications” under 40 CFR 

60.14(e)(5), even if they emit CO2 as a byproduct. The significant majority of projects that the 

EPA believes EGUs are most likely to undertake in the foreseeable future that could increase 

the maximum achievable hourly rate of CO2 emissions would be pollution control projects that 

are exempt under this definition. More details on the approach for modified sources can be 

found in the preamble.

EPA is not proposing a standard of performance for modifications at this time. As a 

result, sources that undertake modifications will be treated as existing sources and thus not 

subject to the requirements proposed in this notice, although they would be subject to 

requirements that the EPA intends to propose separately for existing EGUs. The EPA is soliciting 

comment on the treatment of modified sources and, depending on the information received, 

may issue proposed standards of performance in the future. 

2.2.4 Transitional Sources

This proposed rule sets no standard for transitional sources, although these sources may 

be subject to an existing source standard in a subsequent rulemaking. In this proposal, EPA 

identifies transitional sources as those sources that have received permits to construct, but 

have not actually commenced construction. EPA believes that there are approximately 15 units 

that would be classified as transitional sources (see Appendix 2A for a list of potential 

transitional units). EPA is proposing that as long as these units commence construction within 

one year of the effective date of this proposal, these sources will be classified as transitional 

sources for the purposes of this rule and will not be subject to the NSPS.

Historically, obtaining a permit does not guarantee that a unit will be constructed. In 

the last 10 years, 85 coal plants have been permitted. Of those, 40 (or less than half) have 
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actually commenced construction. Thirty projects have been cancelled and approximately 15

sources (the transitional sources) have active permits. EPA notes that many variables in 

addition to permitting appear to contribute to the likelihood of project completion. Based on

this history and current economic conditions in particular, not all units are likely to proceed. 

EPA believes the transitional units that are most likely to commence construction are 

those that have received government incentives to install CCS. These units would be able to 

commence construction within the proposed rule time-frame. 

2.2.5 Reconstructed Sources

The EPA’s CAA section 111 regulations provide that reconstructed sources are to be 

treated as new sources and, therefore, subject to new source standards of performance. The 

regulations define reconstructed sources, in general, as existing sources: (i) that replace 

components to such an extent that the capital costs of the new components exceed 50 percent 

of the capital costs of an entirely new facility and (ii) for which compliance with standards of 

performance for new sources is technologically and economically feasible (40 CFR 60.15). 

Historically, very few power plants have undertaken reconstructions. We are not aware 

that any power plants are presently planning any project that could meet the requirements for 

a reconstruction. In light of this limited experience concerning reconstructions, the Agency lacks

adequate information that is needed to propose a standard of performance for reconstructions. 

As a result, in today’s action, the EPA is not including a proposal for reconstructions. Instead, 

we solicit comment on how we should approach reconstructions and, depending on the 

information we receive, we may propose and finalize a standard for reconstructions at a later 

time. EPA is soliciting comment on the type of source that will undertake reconstruction; the 

type of changes; the extent of emissions increases; and the type of control measures, including 

their cost and emissions reductions.

2.2.6 Existing Sources 

For the purposes of this rule an existing EGU is defined as any fossil fuel-fired 

combustion unit that has the potential to produce more than 25 MW output and serves a 

generator that produces electricity for sale and was in operation or commenced construction 

on or before publication of this proposed rule. Existing sources are not covered in this 

proposed action, but will be addressed in a subsequent rulemaking by the EPA.
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2.3 Control Strategies

This proposal requires that all new fossil-fuel fired units with greater than 25 MW

capacity be able to meet an emission rate standard of 1,000 lb CO2/MWh calculated over a 

rolling 12-month period. It also proposes an alternative compliance option that would allow 

units to meet the 1,000 lb CO2/MWh standard using a 30-year averaging period. These 

standards could be met by NGCC generation with no additional GHG control or coal-fired 

generation using carbon capture and sequestration technology. 

2.4 Analytical Baseline 

EPA used IPM v.4.10 to assess the baseline conditions described for the proposed new 

source performance standards. IPM is a dynamic linear programming model that can be used 

to examine the economic impacts of air pollution control policies for CO2 and other air 

pollutants throughout the contiguous U.S. for the entire power system. The modeling 

conducted for this proposal is discussed more extensively in Chapter 5 of this RIA. 

Documentation for IPM can be found in the docket for this rulemaking or at 

http://www.epa.gov/airmarkets/progsregs/epa-ipm/index.html. For more information on the 

analytical baseline see Chapter 5 of this report.

2.5 Emission Reductions 

As will be discussed in more detail in Chapter 5 of this RIA, the EPA anticipates that the 

proposed EGU GHG NSPS will result in negligible changes in GHGemissions over the analysis 

period (through 2020). Even in the absence of this rule, the EPA expects that owners of new

units will choose generation technologies that meet these standards due to expected economic 

conditions in the marketplace. Likewise, we anticipate that this rule will have negligible costs, 

quantified benefits, and impacts on the price of electricity, labor markets, or the economy. 
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APPENDIX 2A

POTENTIAL TRANSITIONAL UNITS

Plant Name Size CO2 Mitigation Plan Location

Trailblazer 600 MW CCS – EOR (supercritical PC) TX

Taylorville 602 MW CCS – EOR/Geologic (IGCC) IL

Texas Clean Energy 

Project 400 MW CCS – EOR (IGCC) TX

Cash Creek Generation 761 MW CCS - IGCC KY

Power County Advanced 

Energy Center 520 MW CCS – EOR (IGCC) ID

Good Spring 270 MW CCS – IGCC PA

Limestone 3 750 MW Agreement to capture or offset 50% of 

CO2 (subcritical PC) – CCS ready TX

Holcomb 2 895 MW None (supercritical PC) KS

White Stallion 1320 MW None (subcritical CFB) TX

James De Young 78 MW None (subcritical CFB) MI

Wolverine 600 MW None (subcritical CFB) – CCS ready MI

Coleto Creek 650 MW None (supercritical PC) – CCS ready TX

Washington County 850 MW None (supercritical PC) GA

Bonanza 110 MW None (subcritical CFB, waste coal) UT

Two Elk 250 MW None (subcritical PC, waste coal) – CCS 

ready WY

Note: This table does not reflect an official list of transitional sources, but instead reflects sources that could potentially be 

considered transitional under the proposed regulation.

PC = pulverized coal

CCS = carbon capture and storage

CFB = circulating fluidized bed

EOR = enhanced oil recovery

IGCC = integrated gasification combined cycle