PART 231

State Implementation Plan Equivalency Determination

February 3,2009

The New York State Department ofEnvironmental Conservation (Department) has determined that

its New Source Review (NSR) program in 6 New York Codes Rules and Regulations (6NYCRR),

Part23l- (New Source Revierv For New And Modified Facilities) is equivalent to the federal NSR

program. The Environmental Protection Agency (EPA) in its December 31, 2002 NSR rule, stated

at page 57 FR 80241that States can customize their NSR programs '\vith different but equivalent

regulations". New York State has developed a customized NSR program. Revised Part 231 does

contain provisions that are "different but equivalent" to the provisions of the December 31,2002

NSR rule as amended on December 21,2007 (Federal NSR Rule).

The Department has incorporated into revised Part23l the NSR applicability concepts provided

in the Federal NSR Rule. Generally, these concepts include 1) Baseline period (look-back

period) for determining baseline actual ernissions, 2) Baseline actual emissions-to-projected

actual emissions test for emission increases, 3) Plantwide Applicability Limits (PALs), and 4)

Reasonable Possibility Recordkeeping and Monitoring requirernents for insignificant

modifications. In several instances the Department has expanded and strengthened EPA's

concepts to provide additional safeguards. There are several instances where the requiranents of

revised Part23l deviate from the Federal NSR Rule, however, the Department maintains that

revised Partz3l is equivalent to the Federal NSR Rule.

The discussion below addresses those instances where the provisions of revised Part 231 are

"different but equivalent" to the Federal NSR Rule.

1.) Baseline Period - The Department has decided to establish a uniform baseline period

provision for eledtric utility steam generating units (EUSGUs) and non-EUSGUs. Revised Part

231 requires that all emission sources select a baseline period usingany twenty-four (24)

consecutive month period within the five (5) year period that precedes a proposed change,

adjusted to reflect current enforceable ernissions limitations. Under the Federal NSR Rule,

baseline actual emissions for non-EUSGUs are to be calculated by taking an average of the

annual ernissions in any twenty-four (24) consecutive month period within the ten (10) year

period that precedes a proposed change, adjusted to reflect current enforceable emissions

limitations. For EUSGUs, the Federal NSR Rule limits the baseline period to any twenty-four

(24) consecutive month period within the five (5) year period immediately preceding whan a

permittee begins actual construction of a project or another twenty-four (24) consecutive month

period that is demonstrated as being more representative of normal emission source operations.

Under revised Part23l, both EUSGUs and non-EUSGUs are not allowed to go beyond the most

recent five (5) year period in establishing their baseline emissions.

The Department believes that the revised Part23l uniform baseline period using any twenty-four

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(24) consecutive month period within the five (5) year period that precedes a proposed change

strikes the most appropriate balance considering environmental protection, administrative

burden, business cycles and economic growth. The Department believes that overall this

approach will still provide additional flexibility for facilities, which EPA concludes could result

in additional economic growth. Lastly, the business cycle study relied upon by EPA to justifu its

ten (10) year baseline period, found business cycles varied in the industries surveyed from three

years to eight years. A five (5) year look-back period offers a baseline period that is

approximately the average length of these cycles, while providing further protection than the

EPA allowed ten (10) year baseline period from the opportunity to use a non-representative and

possibly infl ated baseline.

Based on the.above, the Department maintains that a baseline period using any twenty-four (24)

consecutive month period within the five (5) year period that precedes a proposed change,

adjusted to reflect current enforceable emissions limitations best represents the goals of the NSR

program for the State, and although different than the federal requirements, is equivalent to the

federal requirements.

2.) Sihgte Baseline For facilities Undergoing NSR Modifications - Revised Part 231 requires

that facilities select a single baseline period for all NSR pollutants when calculating'baseline

actual emissions for a specific prbject. The Federal NSR Rule, allows facilities to choose a

different baseline period for each NSR pollutant. The Department has determined that a single

baseline period for a specific project is more protective of the public health and the environment

and is the only reasonable altemative for the New York's NSR program.

The Department considered two alternatives with respect to the definition of Baseline Actual

Emissions: (,1) adopt the federal definition or (2) adopt a definition based on the federal rule but

tailored to the needs of New York State. The Department believes that the federal definition has

the potential to inflate the calculation of baseline actual emissions, thereby subjecting fewer

projects to NSR review and potentially result in higher air emissions in the State. Pursuant to the

Federal NSR Rule, a facility could develop a baseline emissions profile which is not derived

from a permitted operating scenario, but is based on pollutant-specific emissions achieved during

different operating scenarios and different baseline periods. In practice, the facility would not

have emitted at the two-year high levels for all the NSR contaminants during any consecutive

twenty-four (24) month period. More importantly, the operating permit would not have

authorized such emission levels under either operating scenario.

The use ofa single baseline period assures that a proposed project is based on an actual

operating scenario and not an artificially high emissions baseline. The use of multiple baselines

could result in picking several baseline periods to maximize emissions for several different

pollutants. For example, a combustion facility permitted to burn both oil and natural gas could

choose different baseline periods when using natural gas to maximize VOC, CO, and PM-10

emissions and oil to maximize PM, NOX and SO2 emissions. This would create an artificially

high baseline never actually experienced by the source nor emitted to the atmosphere surrounding

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j* P:lttP Td, iL extreme cases, a baseline that could never actually be achieved by the source.

With higher baseline emissions during a particular twenty-four (24) month period, a proposed

project could potentially avoid being subject to NSR for those pollutants as-a result of selecting

that baseline period. At no time would the actual ernissions of the affected emissions source in

any one operating scenario be honored, notwithstanding that the Department's part 201

permitting program establishes emission limits for each operating scenario. The result of this is

the potantial for a project that would otherwise be considered major except for the artificially

high baseline to either "cap out" or "net out" of NSR. This would cause an irr"r"as" in emissions

that would exacerbate air quality problans in New york State.

The use of a single baseline period over five (5) years provides the source owner sufficient

flexibility to choose an operating scenario that best reflects operating conditions during the

normal business cycle without unnaturally inflating emissions. por t-his reason, the Department

believes a single baseline period is the only reasonable methodology to determine baseline actual

emissions. This single baseline period will be a scenario that has uitrutty occurred and was

experienced by the source and the environment. Based on the above, the Oepartment believes

that a single baseline period best represents the goals of the NSR program foi the State, and

although different than the federal requiranents, is equivalent to the federal requirements.

3.) Reasonable Possibility In Recordkeeping - Revised Part23l expands upon the

requirements of EPA's December 21,2007 final Reasonable Possibility In Recordkeeping rule by

incorporating recordkeeping and/or monitoring requiremants for all insignificant 11odifi"oltiorrr. 

-

EPA's final rule only includes provisions applicable to: 1) modifications with a projected actual

emissions increase that equals or exceeds fifty (50) percent of the applicable NSR significance

threshold, and2) modifications with a'projected actual emissions increase that is less than fifty

(50) percent of the applicable NSR significance threshold but when ernissions attributable to

independent and unrelated factors such as dernand growth are added, equals or exceeds fifty (50)

percent of the applicable NSR significance threshold. For the first scenario, EpA requires

emission sources to.comply with both pre-change and post-change recordkeeping and reporting

requirements. For the second scenario, EPA requires only pre-change recordleeping

requirernents.

Unlike EPA's December 21,2007 final Reasonable Possibility In Recordkeeping rule, revised part

231 expands the reasonable possibility in recordkeeping requiranents by:

I .)' requiring that any modification with a project emission potential (EPA's projected actual

emissions increase) which is less than 50 percent of the applicable significant project

threshold, or any modification with a project emission potential which when emissions from

independent and unrelated factors such as demand growth are added, is less than 50 percent

of the applicable significant project threshold, in addition to complying wiih any

requirements under Part2}l,maintain for a minimum of five years: (l) a description of thl

modification; (2) an identification of each new or modified emission source(s) including the

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associated processes, and ernission unit; (3) the calculation of the project emission potential

for each modified emission source(s) including supporting documentation; and (4) the date

the modification commenced operation. EPA's final Reasonable PossibilitvRule does not

have this requirement for modifications which are below the reasonable possibilitv threshold.

2.) extendingthepost-changemonitorinsrequirementsto also include anymodificationwith

a project emission potential which is less than fifty (50) percent of the applicable significant

project threshold, but equals orexceeds fifty(50) percent ofthe applicable significantproject

threshold when emisbions from independent and unrelated factors such as demand growth

are added. Foi such insignificant modifications, revised Part 231 requires facilities to keep

records of their calculation of emission increases from independent and unrelated factors

such as dernand growth, monitor post-modification emissions, and submit annual reports to

veriff the accuracy of their calculations. Additionally, the final federal Reasonable

Possibility rule only requires EUSGUs to notiff the Department, prior to beginning actual

construction, for any modification with a project onission potential which equals or exceeds

fifty (50) percant of the applicable significant project threshold. Revised Part23l extends

the pre-construction notification requiranent to any facility that proposes a modification with

a project ernission potential which equals or exceeds fifty (50) percent of the applicable

significant project threshold or proposes a modification with a project emission potantial

which is less than fifty (50) percent ofthe applicable significant project threshold, but equals

or exceeds fifty (50) percent of the applicable significant project threshold when emissions

from independent and unrelated factors such as demand growth are added.

The Department believes these additional requiranents are necessary to ensure that facilities take

into account the emissions from all insignificant modifications in any future Part'231applicability

determination such as netting, and best represents the goals of the NSR program for the State, and

although different than the federal requiranents, is equivalent to the federal requirements.

4.) Plantwide Applicability Limits (PALs) - The Department's revised Part 231 allows

facilities to establish a PAL for an initial term not to exceed l0 years consistent with the

provisions of the Federal NSR Rule. The Department's rule, however, aligns the PAL term with

a facilities Title V permit so that the PAL expires when the renewed Title V permit which

includes the PAL expires. This may cause, in some instances, the duration of the initial PAL

term to be less than 10 years. For example, if a PAL is established two years into the Title V

permit term, the PAL will expire in eight years rather than 10 years. This will enable the PAL to

be renewed in conjunction with the Title V permit rather than in a separate proceeding as a major

modification to the Title V permit. The Department believes that a singlg permit process will

facilitate public review of the PAL and the Title V permit and also eliminate the additional costs .

associated with a separate permit application and review process.

Unlike the Federal NSR Rule, the Department's revised Part 231 requires a reduction in the PAL

of up to 25 percent or implementation of best achievable control technology (BACT), whichever

is less stringent, by the end of the fifth year of the initial PAL. The Department recognizes that a

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source operating under a PAL is free to undertake plant changes that might otherwise trigger

NSR emission reduction requirernents. Therefore, the implanentation of a PAL can have the

effect of allowing a facility to avoid the imposition of controls that would result in reduced

emissions. Requiring a reduction in the PAL level by the end of the fifth year of the PAL ensures

that environmental benefits will be achieved by the implementation of the PAL. Although the

Department acknowledges that fewer facilities may opt for a PAL because of the emission

reduction requiranent, the PALs that would not go forward because of the reduction requirement

are necessarily those PALs that would not result in substantial emission reductions.

gur"a on the above, the Department maintains that the PAL provisions of revised Part 231 best

balance the goals of improving air quality in New York State while reducing the burden of NSR

compliance on industry, and although different than the federal requirements, is equivalent to the

federal requironents.

5.) Projected Actual Emissions

Revised Part23lincorporates important safeguards, not found in the Federal NSR rule, to

address the federal rule's lack of enforceability of a facility's projected actual emissions. These

include: (1) a requirement for facilities which net out of major NSR or propose a significant

modification, to obtain a modified permit with an enforceable emission cap based on their

prqjected actual emissions; (2) a requirement that facilities maintain detailed records for a period

of five (5) years for all insignificant modifications, including all relevant documentation

supporting their emissions calculations; and (3) monitoring of emissions to ensure compliance

with the enforceable projected actual emissions limit for facilities which net out of major NSR or

propose a significant modifi cation.

As in the Federal NSR rule, revised Part23l includes in calculating projected actual emissions,

an exernption for emissions from independent and unrelated factors such as dernand growth,

however, revised Part23l includes additional safeguards not required by the Federal NSR Rule

to ensure that facilities do qot misuse the independent and unrelated factors exemption. First, the

rule requires all facilities undertaking modifications to keep records of their projected actual

ernissions, including all supporting documentation. This would include the emissions a facility

excluded from the calculation of projected actual emissions due to independent and unrelated

factors such as demand growth. Revised Part23l also requires that in order for a facility to

include such emissions in determining future compliance, the applicant must have documented

their emissions due to independent and unrelated factors such as demand growth as part of their

permit application. Part 231 requires that any compliance certification include, if applicable,

documentation that actual measured emissions less those attributed to actual demand growth

emissions are below the permitted and enforceable projected actual emissions limit. If a facility

cannot clearly distinguish emissions resulting from the project and those attributable to demand

growth, the facility will have to'attribute all emissions to the project and demonstrate compliance

with permit limits.

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The Department maintains that the additional safeguards noted above, although different that the

federal requirements, are equivalent to the federal requiranents.

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