&EPA
Air and Radiation EPA420-R-05-009
June 2005
United States
Environmental Protection
Agency
Analysis of New York's
Request for Waiver of the
Reformulated Gasoline
Oxygen Content
Requirement for New York
Covered Area:
Technical Support Document
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EPA420-R-05-009
June 2005
of York's for of the
for York
Technical Support Document
Transportation and Regional Programs Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
Docket OAR-2003-0004
Document Number III-B-1
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TABLE OF CONTENTS
EXECUTIVE SUMMARY 1
I. BASIS FOR DEC'S REQUEST FOR A WAIVER 5
II. GENERAL CONCLUSIONS EPA CAN MAKE ABOUT EMISSIONS BASED ON
DEC'S SUBMISSION AND OTHER INFORMATION AVAILABLE 6
III. INFORMATION NEW YORK HAS PROVIDED TO EPA 9
A. Information on VOC emissions 9
B. Information on NOx emissions 10
C. Information on CO emissions 11
D. Information on likely oxygenated RFC composition subsequent to New York's
ban on MTBE 12
E. Information on likely RFC composition subsequent to a waiver of the
oxygen content requirement 13
IV. INFORMATION NEEDED TO EVALUATE NOX, VOC AND CO EMISSIONS
CHANGES RESULTING FROM AN OXYGEN CONTENT WAIVER 14
A. Background 14
B. Emissions Models 15
C. RFC Properties and Composition 17
V. EMISSIONS-RELATED CONCLUSIONS BASED ON NEW YORK'S
SUBMISSION
20
A. Effect of a waiver on NOx emissions based on New York's submission .. 20
1. Multiple gasoline properties affect NOx emissions 20
2. NOx emissions from on-road vehicles with and without a waiver 21
3. NOx emissions from non-road vehicles with and without a waiver22
B. Effect of a waiver on VOC emissions based on New York's submission 22
1. VOC on-road and non-road exhaust emissions 23
2. Evaporative VOC emissions due to RVP increases 24
3. Evaporative VOC emissions due to permeation 26
C. Effect of a waiver on CO emissions 27
D. Ethanol transport-related emissions 27
VI. CONCLUSIONS OF EPA'S ANALYSIS OF DEC'S SUBMISSION 28
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APPENDIX A: SUMMARY OF EPA'S ANALYSIS OF DEC'S SUBMISSION 29
APPENDIX B: EPA'S RESPONSE TO DEC'S REASONS FOR NOT PROVIDING
INFORMATION THAT EPA REQUESTED 30
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EXECUTIVE SUMMARY
Section 211 (k)(1) of the Clean Air Act (CAA) requires that the Administrator of
the Environmental Protection Agency promulgate regulations establishing requirements
for reformulated gasoline (RFC) to be used in gasoline-fueled vehicles in specified
ozone nonattainment areas. The CAA mandates RFC use in certain nonattainment
areas, based on ozone air quality and population criteria. Other ozone nonattainment
areas are allowed to opt into the RFC program. Within the state of New York, RFC is
mandated in the New York City Consolidated Metropolitan Statistical Area (CMSA).
Dutchess County, New York is an opt-in area.
Section 211 (k)(2)(B) of the Act, 42 U.S.C. § 7545(k)(2)(B), establishes an oxygen
content requirement for federal RFC, but allows EPA to waive compliance with the
requirement under certain circumstances. Section 211 (k)(2)(B) provides that:
The oxygen content of the gasoline shall equal or exceed 2.0 percent by
weight (subject to a testing tolerance established by the Administrator)
except as otherwise required by this Act. The Administrator may waive, in
whole or in part, the application of this subparagraph for any ozone
nonattainment area upon a determination by the Administrator that
compliance with such requirement would prevent or interfere with
attainment by the area of a national primary ambient air quality standard.
In a letter dated January 6, 2003 from New York State Department of
Environmental Conservation (DEC) Commissioner Erin Grotty to then Administrator
Whitman, New York requested a waiver from the federal oxygen content requirement
for reformulated gasoline. The submission asserted that because MTBE would be
banned in the State of New York beginning January 1, 2004, and because of the Clean
Air Act's oxygen requirement, ethanol would be used as an oxygenate in the RFC areas
in New York State. DEC further argued that the use of ethanol as a replacement for
MTBE in RFC would result in an increase in volatile organic compounds (VOC) and
oxides of nitrogen (NOx) during the summer ozone season, and that these increases
would prevent or interfere with New York's ability to demonstrate reasonable further
progress to attain and maintain the National Ambient Air Quality Standard for ozone in
its RFC areas.
EPA determined that DEC'S submission did not contain sufficient information and
because New York's submission failed to address the requirements in the statute, EPA
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notified NY that technical and supporting information was needed for EPA to evaluate
the merits of the request. In a letter to DEC dated April 1, 2003, EPA requested
clarification and additional information.1 A subsequent submission dated December 12,
2003 from DEC acknowledged EPA's April 1, 2003 request for additional information.2
DEC provided some additional information in support of its waiver request with this
correspondence, but generally did not provide the information requested by EPA, for
reasons set forth in its letter.3
In order to determine whether the RFC oxygen content requirement prevents or
interferes with New York's ability to attain National Ambient Air Quality Standards
(NAAQS), it is necessary to consider the gasoline quality and related emissions impacts
that would be likely to exist with and without the RFC oxygen content requirement. In
the case of New York, attainment of the ozone NAAQS is the only issue raised by New
York DEC. To evaluate the potential for interference, EPA must first consider the
emissions differences for each pollutant contributing to ozone formation (NOx, VOC and
carbon monoxide (CO)), between cases where the oxygen requirement remains in
effect ("no-waiver") and cases where the oxygen requirement is waived ("waiver"). In
deciding whether to grant or deny a waiver, as a threshold matter EPA must determine
what difference, if any, a waiver would have on emissions, and what effect, if any, the
difference in emissions would have on ambient ozone levels.
Certain underlying information is required in order to make a quantitative
estimate, or even a reasonably certain qualitative directional estimate of the emissions
changes that might occur from a waiver. This information includes knowledge of certain
emission-related fuel properties of the RFC that would be supplied to New York with
and without a waiver. Models relating these fuel properties to vehicle emissions would
then be used to estimate percent differences in emissions between the "no waiver" and
"waiver" conditions. Additionally, area-specific on-road and off-road gasoline emission
inventory data are needed in order to convert relative (%) changes to absolute
(tons/day) changes.
New York DEC'S submissions did not include quantitative estimates of the
emissions differences between "no waiver" and "waiver" scenarios for any of the
pollutants contributing to ozone formation, NOx, VOC and CO. While New York's
submissions did contain quantitative estimates of certain VOC emission changes that
could be associated with the change from MTBE use to ethanol use, these estimates
were incomplete and in some cases unsupported. Changes in NOx emissions from
1 Docket OAR-2003-0004, Document II.C.1.
2 Docket OAR-2003-0004, Document II.D.6.
3 DEC'S stated reasons for not providing the information requested by EPA, and EPA's
responses to those statements (that are not otherwise addressed in the TSD), are set
forth in Appendix B to the Technical Support Document.
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MTBE use to ethanol use were not quantified and changes in CO emissions were not
addressed in New York's submissions.
If New York had provided quantitative estimates of the emission differences
between the "no waiver" and "waiver" situations, EPA's evaluation of its waiver
submission would have included a thorough review of the basis for these estimates (fuel
property estimation and emission modeling methodology), and subsequently, a
thorough review of whether these emission differences indicate that ambient ozone is
likely to be higher with the oxygen requirement than without. However, EPA's initial
review of the information contained in DEC'S waiver submissions determined that it
lacked not only the quantitative estimates of the "no waiver" to "waiver" emission
changes, but the underlying information necessary to make such estimates.
Consequently, EPA asked for additional information and analyses that are 1) necessary
to estimate the effect a waiver might have on the properties of New York reformulated
gasoline, and 2) the effect that this change in fuel properties would have on emissions
from highway and off-road vehicles and equipment. Since this information has not been
submitted, EPA is unable to determine whether implementation of the oxygen content
requirement in the New York RFC area will prevent or interfere with the attainment of a
NAAQS.
EPA has considered the information that New York has provided which may be
relevant to an analysis of New York's waiver request. EPA has determined that the
relevant no-waiver to waiver comparison cannot be made either qualitatively or
quantitatively. In making this evaluation, EPA has considered the information provided
by New York with regard to the potential effect of a waiver on each of the pollutants,
NOx, VOC and CO, for both on-road and off-road gasoline vehicles and engines.
In order to evaluate the information submitted by New York, we have identified
the fuel properties, vehicle fleets (e.g., on-road versus off-road, older technology
vehicles versus newer technology, etc.), and emission sources (e.g. exhaust, "as
blended" evaporative, commingling and permeation-related) that would need to be
considered in a waiver/no-waiver analysis. We have also identified emissions models
and other information necessary to make the relevant emission estimates that could be
utilized to make the waiver/no-waiver comparison.
The information that DEC has provided fails to clearly demonstrate what effect a
waiver would have an on ozone levels in New York. This is because: 1) there are three
pollutants whose emission rates could be altered by a waiver, (NOx, VOC and CO) and
all three affect ozone formation to varying degrees, 2) the lack of information on fuel
qualities with and without a waiver and the lack of other relevant and necessary
information precludes even a directional estimate of the impact of a waiver on NOx and
VOC emissions, 3) the best estimate of the net impact of a waiver on CO emissions is
that CO emissions would be greater with a waiver than without, but the difference
cannot be quantified and 4) no analysis has been provided or performed, and the
information before the agency does not allow an analysis to be performed, on the
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combined effect of these emissions changes on ozone.4
Since no determination can be made regarding the overall effect of a waiver on
ozone-related emissions, the information that DEC has provided fails to clearly
demonstrate what effect a waiver would have on ozone. Since this threshold
demonstration has not been made, EPA is not able to determine whether the oxygen
requirement for RFC interferes with attainment of the ozone NAAQS in the New York
RFC area. EPA concludes that New York's request therefore should be denied.5
CO plays a far less important role in ozone formation that NOx or VOC. Thus, even
though a gross directional determination can be made for CO, such a determination
provides little information in making an overall judgement about ozone formation.
New York has not raised any issue concerning interference with attainment of the
particulate matter (PM) NAAQS. However, our conclusions regarding the PM NAAQS
would be the same as those regarding the ozone NAAQS, i.e., New York has provided
insufficient information to clearly demonstrate what effect, if any, a waiver would have on
PM. This is because New York has not provided sufficient information to determine PM-
related emissions for the no waiver and waiver comparison.
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I. BASIS FOR DEC'S REQUEST FOR A WAIVER
As EPA interprets it, New York's request for a waiver is based primarily on DEC'S
contentions that use of ethanol-oxygenated gasoline will interfere with attainment of the
ozone NAAQS because:
The NOx and VOC emissions performance of ethanol-oxygenated RFC will be
worse than the emissions performance of the MTBE-oxygenated RFC supplied
to New York prior to its MTBE ban.
Commingling and permeation resulting from ethanol use will increase VOC
emissions compared to MTBE-oxygenated RFC.
Ethanol-oxygenated RFC will not provide the NOx reduction benefits expected
under the RFC program because the Complex Model does not fully capture the
effects of oxygenates on vehicle emissions of NOx.
Relaxation of the RFC VOC performance standard for 10 percent ethanol blends,
or granting of 1 psi volatility waivers for 10 percent ethanol blends could increase
VOC emissions.
There would be emissions associated with ships and barges transporting ethanol
into the NY area for adding to RFC at terminals.
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II. GENERAL CONCLUSIONS EPA CAN MAKE ABOUT EMISSIONS BASED ON
DEC'S SUBMISSION AND OTHER INFORMATION AVAILABLE
The only emission modeling which DEC submitted in its January 6, 2003 waiver
request was characterized in its December 12, 2003 letter as "reflecting the potential
impact of ethanol as an oxygenate replacement for MTBE."6 DEC provided no
information on the likely properties of the oxygenated or non-oxygenated RFC that
would be supplied to New York with a waiver, nor has DEC discussed the market share
of non-oxygenated RFC market share should a waiver be granted.7 The only
information supplied by DEC on oxygenated RFC without a waiver is that it is likely to
contain ethanol at 10% by volume. As discussed in Section IV of this document,
information on likely fuel properties would be critical to an estimation of the emissions
differences between the waiver and non-waiver scenarios in New York, as is evidenced
Although comparing emissions associated with MTBE-oxygenated RFC to ethanol-
oxygenated RFC is not the relevant question for EPA's decision on New York's waiver
request, EPA notes that the proffered analysis is inadequate. While EPA agrees with
certain of New York's assertions (e.g., permeation from ethanol and commingling of
ethanol and non-ethanol fuels lead to VOC emissions increases, and there are much less
VOC emissions from these pathways with MTBE use), EPA disagrees with others (e.g.,
the assumptions that VOC emissions will increase with ethanol use as a result of a
volatility waiver or VOC adjustment regulation, discussed below). Furthermore, there are
other considerations related to a switch from MTBE to ethanol that New York simply
ignores, such as differences in the composition of MTBE-oxygenated and ethanol-
oxygenated RFC that may result in emission differences. When all relevant factors and
available information are considered, EPA also cannot determine what the effect on
ozone formation will be from a switch in New York from MTBE-oxygenated RFC to
ethanol-oxygenated RFC.
7 Although the program report enclosed with DEC'S December, 2003 submission included
analyses for the gasolines used in a DEC test program discussed in sections III-C and III-
D below, DEC has provided no basis for EPA to conclude that these formulations are
likely to represent the gasoline that would be supplied were a waiver granted. All fuels
met the 30 ppm sulfur standard. However, the report notes that the ethanol RFC and
non-oxygenated equivalent RFC test fuels were specified to have Complex Model
performance similar to the study MTBE RFC. The MTBE RFC was specified, except for
sulfur, to represent "typical year 2000 NYCMA RFC". No other restrictions or
specifications were imposed on the fuel supplier. As noted, the composition and
emissions performance of actual RFC with or without a waiver will be determined by a
number of regulatory, economic and technical constraints. Consequently the
specifications DEC imposed on the test fuels are insufficient to ensure that they will be
similar to actual future RFC, with or without a waiver.
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by EPA's evaluation of California's waiver request.
In other words, DEC has asked EPA to grant a waiver of the RFC oxygen
requirement, based solely on its assertion that NOx and VOC emissions will increase
with RFC using ethanol when compared to the use of RFC oxygenated with MTBE.
There is a very fundamental problem with New York's analysis. In focusing on the
effect of switching from MTBE use to the use of ethanol as an RFC oxygenate, New
York is addressing the wrong question. In light of New York's ban on the use of MTBE
as an oxygenate, EPA must compare the base case of ethanol-oxygenated RFC
without a waiver to the RFC that would be supplied if an oxygen content waiver were
granted. This is the proper comparison for determining whether continuing to maintain
the oxygen content requirement interferes with attainment of the ozone NAAQS. The
properties of MTBE-oxygenated RFC are irrelevant to this analysis. To put it another
way, maintaining the current oxygen content requirement could not amount to
interference, unless, at a minimum, a waiver is likely to produce a better situation with
respect to ozone-forming pollutants than would exist absent the waiver. As noted, DEC
has not provided information regarding the emission-related properties of the RFC that
would be supplied were a waiver granted, nor did it address the issue of non-
oxygenated RFC market share were a waiver granted.8 As noted, DEC has not
provided the kinds of information necessary to reach this conclusion. In summary, with
the information at hand, EPA cannot estimate no-waiver to waiver emission changes,
as it must do to ascertain whether the oxygenate requirement interferes with NAAQS
attainment.9 This general conclusion is explained in more detail below with respect to
Ethanol-oxygenated RFC could constitute a portion, potentially a substantial portion, of
New York's gasoline pool even if a waiver were granted. DEC may have implicitly
assumed in their submissions that all RFC would be non-oxygenated if a waiver were
granted, but it has provided no information or analysis, such as refinery modeling, to
substantiate this position. This is an issue not only because the pool average emission-
related property values of New York's "waiver" RFC would depend on the extent to which
ethanol is used, but because substantial market shares of both ethanol RFC and non-
oxygenated RFC in New York could result in "worst case" commingling-related VOC
emissions.
In the California waiver analysis, EPA evaluated twelve "no waiver" to "waiver" scenarios.
Each scenario consisted of a set of "no waiver" and "waiver" fuel properties predicted by
refinery modeling with a specific set of assumptions. EPA treated the "no waiver" case as
the reference, computed percent differences in emissions between "no waiver" and
"waiver" fuels, and applied these percent differences to emission inventories to determine
tons/day differences in NOx, VOC and CO emissions. EPA assumed that the tons/day
emission inventory information that was available for the California analysis represented
the all ethanol-oxygenated "no waiver" reference condition. EPA was therefore able to
compute "no waiver" to "waiver" tons/day differences from percent differences in a single
step. While it would be possible in a waiver analysis to calculate emissions changes from
a different reference condition than the "no waiver" baseline, it still necessary to make a
"no waiver" to "waiver" emissions comparison. If a different reference condition (e.g. pre-
MTBE ban) were used, it would be necessary to first estimate both reference to "waiver"
and reference to "no waiver" percent change and tons per day emissions changes, and
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each individual pollutant of concern.
Below are more detailed discussions of the information submitted by NY. The
following sections of this TSD discuss EPA's evaluation of the information. Our
evaluation clearly shows that the information is insufficient to come to any definitive
conclusion regarding the effect of an oxygen waiver on ozone.
subsequently combine them to estimate the total "no waiver" to "waiver" changes.
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INFORMATION NEW YORK HAS PROVIDED TO EPA
In a letter dated January 6, 2003 from New York State Department of
Environmental Conservation (DEC) Commissioner Erin Grotty to then Administrator
Whitman, New York requested a waiver from the federal oxygen content requirement for
reformulated gasoline, under Section 211(k)(2)(B).10 The submission stated that
because MTBE would be banned in the State of New York beginning January 1, 2004,
and because of the Act's oxygen content requirement, ethanol would be used as an
oxygenate in the RFC areas in New York State. DEC stated that the use of ethanol as
a replacement for MTBE in RFC would result in an increase in volatile organic
compounds (VOC), and oxides of nitrogen (NOx) during the summer ozone season.
DEC further stated that "increases in these pollutants will immediately interfere with
New York's ability to demonstrate reasonable progress to attain and maintain the
federal ozone standard...".
In a letter dated April 1, 2003 to DEC Commissioner Erin Grotty, EPA asked for
additional information in order to evaluate DEC'S request for a waiver. A subsequent
submission dated December 12, 2003 from DEC acknowledged EPA's April 1, 2003
request, and provided some limited additional information, but failed to provide the
information requested.
In the sections below, EPA describes in detail the information that DEC has
submitted in detail.
A. Information on VOC emissions
DEC argues that the use of ethanol as a replacement oxygenate for MTBE will
result in substantial increases in VOC emissions due to (1) increased permeation
through vehicle components that hold gasoline, (2) commingling of ethanol-blended
fuels with fuels that do not contain ethanol, and (3) possible modifications in regulatory
limitations on fuel volatility.11 DEC has estimated that the use of gasoline with 10%
10 Filed in docket OAR-2003-0004, document number II.D.1
11 Permeation refers to the escape of gasoline constituents through the walls of non-metallic
fuel lines and gasoline tanks. These soft components of automotive fuel systems tend to
be more permeable to ethanol than to other hydrocarbons in gasoline. Thus, ethanol-
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ethanol in a fleet of five million vehicles would increase VOC emissions due to
permeation by 6.1 tons per day, as compared to use of gasoline with 0% ethanol. It has
provided some explanation of the methodology used in deriving this estimate (Enclosure
H of the January, 2003 DEC submission). DEC states that there would also be an
increase in VOC emissions due to commingling of ethanol and non-ethanol blended
gasolines, compared to before the MTBE ban, but does not provide a quantitative
estimate of the increase.
DEC has also provided quantitative estimates of the VOC emissions increases
associated with a 0.3 pound-per-square-inch (psi) and 1.0 psi Reid Vapor Pressure
(RVP) increase, which DEC claims could occur if EPA were to adopt a VOC adjustment
rule for the NY area and if NY were to provide blenders of ethanol-oxygenated
conventional gasoline a volatility waiver. As is discussed in section V.B.2 of this
document, EPA believes that estimations of VOC increases associated with such
regulatory changes are irrelevant to the appropriate analysis for an oxygen waiver.
Nevertheless, DEC estimated emissions increases of 30.2 tons/day with an RVP
increase of 0.3 psi statewide, 67.2 tons/day if there is an increase of 0.3 psi in RFC
areas and 1.0 psi in conventional gasoline areas, and 82.7 tons/day if there is an
increase of 1.0 psi statewide. Some details of their estimation methodology are
provided in enclosure G of their January, 2003 submission.
DEC also notes that there will be emission increases (for both VOC and NOx)
due to the transport of ethanol to the New York City CMSA from production centers in
the Midwest, but has not provided a quantitative estimate of the emission increases that
will occur within the New York City CMSA.
DEC has not identified or quantified any other VOC emission changes (increases
or decreases) that could occur with ethanol use, nor has it clearly stated that no other
significant VOC emission changes will occur.
B. Information on NOx emissions
DEC claims that NOx emissions will increase with the use of ethanol blended
RFC blends tend to result in an increase in evaporative emissions due to permeation
through these components. Commingling refers to the RVP increase (with resultant
emission increase) that occurs when non-ethanol and ethanol-oxygenated gasoline
blends are mixed in the gas tanks of consumer's automobiles. Since the presence of
ethanol causes an increase in the volatility of the gasoline (as measured by the Reid
Vapor Pressure or RVP), such commingling would contribute to an increase in
evaporative VOC emissions. The regulatory changes New York refers to concern
regulations that provide an allowance for higher VOC emissions when ethanol RFC is
used in the Chicago and Milwaukee area, and potential allowances New York could
provide when blenders add ethanol to conventional gasoline. As is discussed in section
V.B.2 of this TSD, there is no basis to expect that such changes would occur and,
therefore, they are not relevant to an appropriate oxygen waiver analysis.
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RFC compared to MTBE-blended RFC, but has not quantified the anticipated
increases. DEC stated in its January, 2003 letter that existing test data indicate that
NOx emissions from newer vehicles increase with ethanol, although it did not explicitly
define "newer vehicles". In its December, 2003 letter, however, DEC states that vehicle
technology has rendered the need for an oxygen content requirement obsolete because
the fuel control systems in modern fuel injected vehicles will compensate for the
additional oxygen in gasoline and that oxygenated gasoline no longer provides a
benefit.12 Additionally, DEC states in its January, 2003 submission that data show that
ethanol causes NOx emissions increases in older vehicles and even more significantly
in nonroad vehicles.
DEC notes that Phase II RFC regulations require refineries to produce gasoline
that reduces NOx emissions by 6.8 percent and VOC emissions by 27.4 percent
compared to 1990 levels, as quantified by the EPA Complex Model. DEC states,
however, that it believes that the EPA Complex Model does not fully capture the effects
that oxygenates such as ethanol have on emissions from current fleet vehicles. It
believes that NOx emissions will increase due to the use of ethanol compared to MTBE,
and that this actual increase in NOx emissions will not be identified by, or constrained
through the use of, the Complex Model to measure RFC compliance with phase II RFC
regulations. The basis for New York's claim is a report prepared by NESCAUM and
submitted as enclosure B of their January 6, 2003 letter.13
C. Information on CO emissions
DEC made no explicit references to the potential effect of a waiver on CO
emissions or the relationship of CO to ozone formation in its January 6, 2003 or
December 12, 2003 letters, but appears to have implicitly claimed that a waiver would
have no effect on CO emissions from newer vehicles. As previously noted, DEC stated
in its December 12, 2003 letter that vehicle technology has rendered the need for an
oxygen content requirement obsolete because the fuel control systems in modern fuel
injected vehicles will compensate for the additional oxygen in gasoline.
DEC claimed that it has verified the lack of need for an oxygenate through
laboratory testing of two automobiles both with and without oxygenated fuel in a study
DEC provided, with its December 12, 2003 submission, entitled "Emission Impacts of
12 In essence, DEC is saying in its December, 2003 letter that ethanol will not affect exhaust
emissions in newer vehicles because fuel control systems will compensate for the
additional oxygen in gasoline. This appears to contradict the earlier argument that NOx
emissions from newer vehicles will increase with ethanol.
13 "Health, Environmental, and Economic Impacts of Adding Ethanol to Gasoline in the
Northeast States"; New England Interstate Water Pollution Control Commission,
Northeast States for Coordinated Air Use Management; July, 2001. See Volume 1, page
11 and Volume 2, page 11.
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Fuels to Accommodate the NY State Oxy-waiver Request and MTBE Ban."14 This study
describes a test program conducted at DEC'S Automotive Emissions Laboratory (AEL),
in which two vehicles, a 1998 Plymouth Breeze and a 1997 Oldsmobile Achieva, were
tested multiple times using an MTBE-oxygenated RFC, an ethanol-oxygenated RFC,
and a non-oxygenated "equivalent RFC". The program report concluded that data from
over 200 emission tests on these two vehicles do not indicate any consistent increase in
any of the regulated emission species (HC, CO, NOx) for either the ethanol-oxygenated
RFC or the non-oxygenated "equivalent RFC" relative to the MTBE-oxygenated RFC.
D. Information on likely oxygenated RFG composition subsequent to New York's
ban on MTBE
DEC has provided EPA with very little information on the likely emission-related
properties of its RFG subsequent to an MTBE ban.15 These properties will determine
the exhaust and evaporative emissions associated with RFG use in a non-waiver
scenario.
NY stated in its December 12, 2003 letter that refiners will, almost uniformly, be
blending 10 (volume) percent ethanol. This is equivalent to approximately 3.5 weight
percent oxygen. Blending at approximately 5.7 volume percent ethanol is required to
meet the 2 weight percent RFG oxygen requirement, but, according to DEC, tax
incentives and other considerations will likely lead refiners to blend ethanol at 10%.
Beyond this, NY has provided no further information on the probable composition of
ethanol-oxygenated RFG subsequent to its MTBE ban.16
14 "Program Report: Emission Impacts of Fuels to Accommodate the NY State Oxy-waiver
Request and MTBE Ban", May 6 ,2003, submitted as an enclosure to DEC'S December
12, 2003 letter.
15 These emission-related properties are the parameters used in emission models to
estimate emission differences resulting from fuel formulation differences. The Complex
Model inputs affecting VOC and NOx emissions are RVP, oxygen wt%, aromatics vol%,
olefin vol%, sulfur ppm, E200 and E300. (E200 and E300 are the percent of gasoline
evaporated at 200F and 300F, respectively.) The alternative Tech 4 models which EPA
developed for its California waiver analysis use RVP, oxygen wt%, aromatics vol%, olefin
vol%, sulfur ppm, T50 and T90 as inputs . (T50 and T90 are the temperatures at which
50% and 90% of the gasoline are evaporated, and are highly correlated with E200 and
E300.). As discussed later, these models should be applicable to a portion of New York's
on-road fleet, as well.
1R
DEC does suggest that the as-blended Reid Vapor Pressure (RVP), could increase from
current levels, either because of a change in the RFG VOC emission performance
standard, such as that which EPA allowed in Chicago and Milwaukee (VOC adjustment
rule), or because of a 1.0 psi volatility waiver available for 10% ethanol-blended
conventional gasoline. As is discussed in section V.B.2 of this document, such changes
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The program report for DEC'S vehicle testing study, cited earlier, included
certificates of analysis showing properties for the gasolines used in the study. The
report states "AEL believes that the study fuel specifications approximate the fuel
blending situation that refiners will face upon implementation of the NY MTBE ban."
EPA is unsure if DEC was suggesting that the ethanol-oxygenated and non-oxygenated
RFC formulations described in the study are likely to represent New York's RFC with
and/or without a waiver, subsequent to an MTBE ban. Since the ethanol-oxygenated
RFC formulation in this study was not blended with 10 volume percent ethanol, EPA
assumes that DEC would not consider it to be representative of New York's "no waiver"
ethanol-oxygenated RFC.
E. Information on likely RFG composition subsequent to a waiver of the
oxygen content requirement
DEC did not explicitly address this issue in the text of either submission letter.
Except as noted in the previous section and in footnote 7, DEC provided no description
of the potential composition of RFG were a waiver granted.
are not expected to occur and, therefore, are not relevant to an appropriate oxygen waiver
analysis.
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IV. INFORMATION NEEDED TO EVALUATE NOX, VOC AND CO EMISSIONS
CHANGES RESULTING FROM AN OXYGEN CONTENT WAIVER
A. Background
RFC, in order to comply with statutory and regulatory requirements, must meet
certain emissions performance and content standards. The emission performance
standards are specified as percent reductions in NOx, VOC and toxics emissions
relative to emissions with a statutory baseline gasoline having properties representative
of 1990 gasoline. These reductions are calculated by the Complex Model, which
estimates the emissions that 1990 technology vehicles would achieve when using both
the statutory baseline gasoline and any RFC formulation that is being evaluated. The
Complex Model calculates a percent reduction between the baseline gasoline and the
RFC at issue. (The properties which are inputs to the Complex Model have previously
been identified in a footnote.) RFC is also subject to oxygen and benzene content
standards. It must contain, on average, at least 2.1 weight percent oxygen and no more
than 0.95 volume percent benzene. In addition to the requirements imposed by the
RFC standards, both RFC and conventional gasoline (CG) are also affected by the
Mobile Source Air Toxics (MSAT) regulations. These regulations cap Complex Model
toxics emissions at their 1998-2000 levels on a refinery-specific basis.17 The Tier 2
gasoline sulfur requirements, when fully implemented, will require an average sulfur
level of 30 ppm or less in both RFC and CG.18
RFC producers must meet these emission-related regulatory constraints, and
also must supply RFC and CG that meets octane and other driveability-related
requirements. Refiners attempt to produce gasoline and other products in the most
economically advantageous manner, subject to these constraints. The manner in which
a given refinery meets this objective depends on the configuration of the refinery, the
cost and availability of various blending components (e.g. MTBE, ethanol, and alkylate
which have good octane characteristics), and other technical and economic factors.
Consequently:
17 Since much RFC overcomplied with toxics performance requirements, MSAT imposes a
tighter constraint on RFC composition than the RFC performance standard for many
suppliers.
18 The sulfur level in RFC is currently constrained by RFC performance standards, but the
Tier 2 sulfur content requirement imposes a tighter constraint.
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RFC emission performance and content standards alone do not determine
RFG's composition. Other factors may provide additional constraints on certain
emission-related properties.
RFC composition without a waiver is not uniform across refiners and refineries.
Complex Model emission performance varies and much RFC overcomplies,
particularly with the NOx and toxics standards. Emissions performance for New
York's RFC cannot be fully evaluated without estimates of all the relevant fuel
properties which are inputs to the Complex Model.
The same factors that lead to variety in RFC composition and emissions
performance without a waiver would lead to variety in RFC composition and
emissions performance with a waiver.
Even though RFC must meet the same Complex Model performance standards
with or without an oxygen waiver, the actual emissions performance may be
different with and without a waiver because the composition of the fuel is likely be
different with and without a waiver.
B. Emissions Models
Emission performance, as measured by the Complex Model, is a function of
several fuel parameters. The relationship between emissions and gasoline properties
was determined by statistical regression analysis, using several thousand vehicle
emission tests from a number of different studies. Development of the Complex Model,
or any comparable model, such as California's Predictive Model, requires a number of
decisions, some of which are subjective. Additionally, there are choices in the statistical
techniques that can be used to develop these models. Thus, different models, showing
different relationships between fuel properties and emissions for the same pollutant, can
reasonably result from the same data set.
EPA developed updated models for NOx and exhaust VOC in order to evaluate
California's RFC oxygen content waiver request, using data which California used to
develop its Predictive Model. Much of these data were also used to develop EPA's
Complex Model. These alternative models could be applied to a New York waiver
analysis. While these EPA models differ from the Complex Model, particularly with
respect to the relationship of NOx and oxygen, these models require the same basic
fuel property information as inputs.
In order to evaluate the effect of a change in fuel properties on vehicle emissions,
it is common practice to separate the vehicle fleet into several technology groups. It is
widely believed, and supporting data indicate, that different technology groups respond
differently to fuel property or composition changes. In the California waiver evaluation,
vehicles were divided into three technology groups: older technology vehicles (pre-1986
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model years), mid-age technology vehicles (model years 1986 through 1995) and newer
vehicles (model year 1996+). These older, mid-age, and newer technology vehicles
were referred to as Tech 3, Tech 4, and Tech 5 vehicles respectively.
EPA's alternative NOx and exhaust VOC models, like the Complex Model, are
designed to predict emissions from only a portion of the gasoline mobile source fleet. In
its California waiver analysis, the alternative NOx and exhaust VOC models which were
developed represented the Tech 4 portion of California's light duty vehicle fleet. Based
on California's EMFAC7G emission model, Tech 4 vehicles are expected to be the
second largest contributor of the three tech groups to California's NOx emission
inventory and the largest to its exhaust VOC inventory in 2005. (While the Tech 5
vehicles may have the largest contribution of these three tech groups to the NOx
inventory, there were insufficient data to produce Tech 5 fuel effects emission models
comparable to the Tech 4 models, and engineering reasons to assume that Tech 5
vehicles may not be substantially affected by certain fuel parameter changes).
EPA assumed in the California waiver analysis that newer "Tech 5" vehicles
(model years 1996+) would not respond to changes in oxygen content or other fuel
parameter changes. EPA assumed, as does DEC, that fuel control systems in modern
fuel injected vehicles will compensate for the additional oxygen in gasoline.19
EPA used the "Tech 3" model portion of California's phase 3 predictive model
representing model year 1981-85 technology, to estimate emissions changes that would
occur in older vehicles. EPA also had emission weighting factors, which were part of
California's phase 3 predictive model and which estimated the relative contribution to
emissions in year 2005 of these three technology groups. This allowed EPA to combine
separate percent change emission estimates for each of these technology groups into a
single percent change estimate, and apply this percent change to an on-road gasoline
NOx and exhaust VOC emission inventory (in tons per day). This allowed EPA to
estimate overall on-road gasoline NOx and exhaust VOC no-waiver to waiver emission
differences in tons per day.
EPA believes that an approach utilizing these models, with weighting factors
appropriate for New York, could be used by New York to perform the appropriate
emissions modeling for on-road vehicles in a waiver application.
In its analysis of the California waiver, EPA assumed that changes in emissions
from off-highway or non-road engines would be a function of oxygen content only, using
19 While the assumption regarding no effect certainly does not apply to the relationship
between gasoline sulfur content and NOx performance for these newer Tech 5 vehicles,
in its California waiver analysis EPA was comparing waiver and non-waiver fuel
formulations which had very small differences in sulfur content. Thus, the assumption that
the sulfur content had no effect on "Tech 5" emissions introduced little or no error in that
analysis.
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factors (in percent change in emissions per weight percent of fuel oxygen added)
published in EPA Report No. NR-003, as the basis for its estimate of percent changes in
non-road emissions. Barring new information, it would be reasonable to apply these
same non-road factors in a New York analysis.
In its California analysis, EPA had emission inventory information for both on-
road and non-road mobile sources. Thus, knowing oxygen content and other fuel
properties, and oxygenated/non-oxygenated market share for each waiver case, EPA
was able to estimate the percent difference in emissions between waiver and non-
waiver scenarios, apply this difference to the inventory to estimate a tons/day difference
and combine the on-road and non-road changes.
For the reasons described in EPA's California waiver analysis20, EPA assumes
that carbon monoxide emissions would be primarily affected by fuel oxygen content,
with CO emissions increasing as oxygen content decreases. For California, EPA
modeled on-road CO changes using "percent reduction per weight percent oxygen
increase factors" published in a California Air Resources board staff report.21 EPA used
factors from NR-003, cited earlier, to model off-road CO changes. The on-road percent
changes may be somewhat California-specific, since they were derived from California's
EMFAC emission factors model. It is probably more appropriate to quantify the CO
emission changes in New York using the Mobile model.
In summary,
There are models which may be superior to the Complex Model for evaluation of
on-road vehicle emissions differences in New York with and without an
oxygenate waiver
These alternative models require essentially the same fuel property information
as the Complex Model, and emission performance for New York's RFC cannot
be evaluated using these models without estimates of all the fuel property inputs.
It is reasonable to estimate off-road exhaust emission and on-road CO changes
from oxygen changes alone and the methods to estimate these emission
changes could (if the requisite information were available) be used in evaluating
a waiver request in New York.
20 EPA Docket A-2000-10, Docket Number ll-B-2.
21 California Air Resources Board (GARB) Staff Report: Initial Statement of Reasons;
Proposed California Phase 3 Reformulated Gasoline Regulations; released October 22,
1999.
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C. RFG Properties and Composition
Knowledge of the likely formulation of RFG in New York with and without an
oxygen content waiver is critical to EPA's evaluation of whether or not the oxygen
content mandate interfered with attainment of the ozone NAAQS. Because this
information has not been provided, EPA is not able to conclude what effect a waiver
would have on vehicle emissions in the NY RFG area. Some information exists
regarding the composition and properties of ethanol-oxygenated RFG 22 supplied to
New York during the ozone season subsequent to New York's MTBE ban. This RFG
does not, on average, meet the ultimate 30 ppm sulfur requirement which the Tier 2
gasoline sulfur regulations will impose on both conventional and reformulated gasoline,
but reflects transitional sulfur requirements which become more stringent over a multi-
year period. Even though these data do not represent full implementation of the Tier 2
sulfur requirement, they are likely to be somewhat informative of the composition of the
RFG that will be supplied to New York in the future in the absence of an oxygen content
waiver.23 However, these data do not predict the composition and properties of the
RFG that would be supplied to New York if a waiver were granted. Consequently, this
information, by itself, is insufficient to evaluate the impact of an oxygen content waiver.
New York's submissions provide no source of real world data or predicted data
that is informative of the composition of the RFG that would be supplied to New York if
EPA waived the oxygen content requirement. In its waiver submission, California relied
on refinery modeling studies to predict the properties of California Phase 3 RFG
(CaRFGS) and, similarly, EPA relied on expansions of these same refinery modeling
studies to evaluate California's submission. These studies predicted the properties of
the CaRFGS that would be produced if an oxygen content waiver were granted, as well
as the properties of the oxygenated CaRFGS that would be produced without a waiver.
This modeling was conducted on those refineries supplying RFG to California, so is
22 RFG surveys are conducted each year by the RFG Survey Association, an association of
refiners, importers and oxygenate blenders. Gasoline samples are collected at retail
stations in RFG covered areas, under a survey plan which EPA approves, and analyzed
for emission-related properties. Independent contractors perform the sample collection
and analysis. These surveys are required by 40 CFR 80.67, for suppliers who choose to
meet RFG standards on an average basis, rather than on a "per gallon" basis. These
surveys are intended to ensure that the RFG supplied to each covered area meets
standards. Specific requirements pertaining to these surveys can be found in 40 CFR
80.68.
23 EPA has published average property information from RFG surveys through 2003.
Although 2004 averages have not been published, EPA would have provided data from
2004 surveys to New York DEC as soon as it was available, had it been requested.
Ozone-season RFG surveys in NY were conducted between June and late August. EPA
receives data approximately 30 days after each survey is completed and received all
ozone season survey data for NY prior to October, 2004.
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California-specific.24 Furthermore, California reformulated gasoline standards, which
are applicable to RFC sold in federal RFC areas in California, differ from federal RFC
standards. Thus, the predictions of the California fuel properties from this modeling are
not applicable to the analysis of the New York waiver since different modeling
constraints would be applied for the California case versus the New York case. For
example, modeling indicated that it was infeasible for California refiners to make RFC
oxygenated at 10% ethanol, while New York is likely to receive 10% ethanol during the
ozone season.25 The California modeling does predict that substantial amounts of
ethanol-oxygenated gasoline would be used in California, even with a waiver of the
federal RFC oxygen content requirement. Although the California analysis is certainly
not directly applicable to New York, the expected use of ethanol in California
demonstrates that, lacking information to the contrary, EPA cannot assume that ethanol
will not be used in New York in a waiver situation. Ethanol may be used to make up, in
part, for the volume and octane which MTBE provided even if EPA waived the oxygen
content requirement. Other studies support such a conclusion.26
24 In fact, refinery modelers typically use completely different models to estimate the
composition of gasoline produced for the New York area versus gasoline produced for the
California market.
25 The modeling which EPA commissioned for the California waiver analysis represented the
characteristics of the California refinery system. Additionally, the modeling required that
California Phase 3 RFC meet California standards for NOx and hydrocarbons based on
California's Phase 3 predictive model, rather than the Complex Model. Thus, the RFC
modeled for the California waiver analysis was required to meet a much more stringent
NOx standard than the Federal standard. Additionally, since the predictive model, unlike
the Complex Model, indicates that NOx emissions will increase as oxygen content
increases, California's NOx performance requirements impose a practical limit on weight
percentage of oxygen that can be used in California blends. Consequently, EPA has little
confidence that the forecasts of emission-related fuel parameters which these models
produced would be applicable to New York.
26 The NESCAUM report submitted as enclosure B of NY's January 6, 2003 submission
states on page 9, vol.2 "If the oxygen requirement were waived or lifted, it is highly likely
that some amount of ethanol would still be blended into RFC..."
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V. EMISSIONS-RELATED CONCLUSIONS BASED ON NEW YORK'S
SUBMISSION
A. Effect of a waiver on NOx emissions based on New York's submission
1. Multiple gasoline properties affect NOx emissions
With regard to DEC'S comments regarding the complex Model, EPA does agree
that the Complex Model may over-estimate the NOx emission performance of certain 10
v% (about 3.5 wt% oxygen) ethanol-oxygenated RFC blends, because the Complex
Model does not show a NOx increase with increasing oxygen. According to EPA's
models developed during the California waiver analysis and readily available to NY
DEC, all other properties being equal, as oxygen content increases, NOx emissions will
also increase for Tech 4 vehicles. Thus, if two RFC blends with different oxygen
content were formulated to have the exact same Complex Model NOx performance
(e.g. 6.8 percent reduction from 1990 baseline, the averaged standard), EPA would
suspect that the "true" NOx performance of the blend with the higher oxygen content
would be worse than that of the blend with the lower oxygen content. The problem with
this simplistic argument is that there are many properties and components of RFC other
than oxygen content which would likely be different in a waiver versus no-waiver
scenario, and these other properties and components also affect NOx emissions. (This
is discussed in the previous section of this TSD.) Thus, neither the magnitude nor
direction of a NOx change can be predicted using the data submitted by DEC since the
argument above is based only on oxygen content.27
27 Although oxygen increases taken alone (i.e., all other properties being equal) directionally
increase NOx emissions in EPA's alternative models for Tech 4 vehicles, real world
situations clearly show that other RFC properties can and do change the magnitude and
even the direction of this change. In EPA's evaluation of California's waiver request using
the alternative models, NOx emissions clearly go down where average oxygen content of
the gasoline pool is lower (i.e., all of the waiver scenarios). However, in other real world
situations fuels can exhibit better NOx performance even with higher oxygen content due
to differences in other properties that affect NOx emissions. To further illustrate this point,
EPA has examined "real world" VOC-controlled RFC survey data collected during the
2003 ozone season and computed two sets of average fuel properties, one from an RFC
area with lower oxygen content and one from an area with higher oxygen content. EPA
utilized averages from surveys conducted in the New York-New Jersey-Long Island-
Connecticut area to represent the lower oxygen content RFC, and averages from
Louisville, Kentucky surveys to represent the higher oxygen content RFC. EPA computed
the NOx performance for these two "average fuels" using EPA's alternative NOx models.
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2. NOx emissions from on-road vehicles with and without a waiver.
Given property estimates for New York's "waiver" and "no-waiver" gasolines, a
complete waiver submission would presumably use EPA's alternative "Tech 4" NOx
models to estimate the emissions change for a portion of the on-road fleet, since these
models were developed with data that are not California-specific. As explained earlier,
the information which DEC has submitted is insufficient to even determine the expected
direction of the "Tech 4" "no waiver" to "waiver" NOx emission change.
An assumption similar to that made for the California analysis, i.e., that the "no
waiver" to "waiver" fuel property differences would have no effect on exhaust emissions
in "Tech 5" vehicles, would likely be appropriate for NY as long as there was little
difference in the sulfur content of the "no waiver" and "waiver" fuels. While this is
somewhat uncertain prior to the implementation of the 30 ppm Tier 2 standard, this
should be the case with that standard in place. Consequently, it would likely be
appropriate to assume that "Tech 5" "no waiver" to "waiver" emission differences would
be zero.
It would probably be adequate to use the "Tech 3" NOx model portion of
California's phase 3 predictive model to estimate NOx emission changes for older
vehicles. This model, although it was created by California to represent a portion of
their fleet, was not based solely on California vehicles. This model requires the same
fuel parameter inputs as the alternative "Tech 4" NOx models which EPA developed.
Thus, it cannot be used to determine the probable direction of the NOx emission change
without estimates of New York's "no waiver" and "waiver" RFC parameters.
EPA applied California-specific emission weighting factors for Tech 3, 4 and 5
vehicles in its California analysis. They represent the California fleet in 2005 and were
estimated using a California-specific emission factors model. Weighting factors more
applicable to the federal fleet and/or to the New York fleet could be developed with
EPA's Mobile model. However, DEC did not submit the fuel parameter information to
calculate the Tech 3 or Tech 4 emission changes, nor did it develop weighting factors
for the various Tech groups. Therefore, it is not possible, given the data submitted, to
draw any reasonable conclusions about the magnitude or the direction of NOx
emissions changes in on-road vehicles for the New York waiver/no-waiver comparison.
The NOx performance of the Louisville, KY "average fuel" is better than that of the New
York "average fuel" based on the EPA alternative model, even though the oxygen content
of the Louisville "average fuel" was higher. (See Docket OAR-2003-0004 Document II-B-
1.)
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3. NOx emissions from non-road vehicles with and without a waiver
EPA assumes that granting an oxygen content waiver would result in some
decrease in the average oxygen content of New York's RFC.28 In that case, there
would be some percent decrease in non-road NOx emissions with an oxygen content
waiver. However, EPA cannot estimate how much non-oxygenated RFC would be used
if a waiver were granted in New York. Consequently, EPA can only qualitatively
estimate a directional decrease in NOx for non-road vehicles and engines with a waiver.
DEC has not submitted any NOx emission inventory information as part of its
waiver request. While the non-road percent change NOx factors are large, EPA
assumes that the non-road gasoline NOx emissions inventory for New York is small
compared to the on-road gasoline NOx emissions inventory. Consequently, even if
EPA concludes that non-road gasoline NOx emissions will be lower with a waiver, EPA
cannot determine with confidence, based only on a qualitative assessment, whether
total mobile source gasoline NOx emissions would be lower with or without a waiver.
B. Effect of a waiver on VOC emissions based on New York's submission
Evaluating the potential impact of ethanol-oxygenated gasoline on NOx
emissions between a waiver and no-waiver scenario only calls for considering changes
in exhaust emissions. Analysis of VOC impacts is considerably more complex. In
addition to the changes in on-road and non-road exhaust emissions, one must also
consider evaporative VOC emission changes that may occur as a result of "as-blended"
RVP differences between various gasoline formulations.29 There are also other
emission effects that may occur as a result of ethanol use. Commingling of ethanol and
non-ethanol gasolines in vehicle fuel tanks causes increases in RVP which can result in
higher evaporative VOC emissions. Additionally, use of ethanol-oxygenated gasoline is
believed to increase VOC permeation emissions.
28 Although without the appropriate analysis, it cannot be said with any certainty that the
waiver would result in the production of non-oxygenated RFC, at least one refiner has
strongly supported granting New York's request for a waiver. The letter of support from
Tosco Corporation enclosed with New York's January 6, 2003 submission clearly
indicates that less oxygen would be utilized in New York RFC if a waiver were granted.
One would presume that support for a waiver from the refining community would indicate
that at least some refiners would blend RFC without oxygen or the waiver would have no
effect on RFC production.
pq
"As-blended" RVP refers to the RVP resulting from blending at a refinery or terminal. It is
distinct from the RVP that may exist in commingled fuel in a vehicle fuel tank.
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1. VOC on-road and non-road exhaust emissions
As previously noted, for its California waiver analysis EPA developed alternative
exhaust hydrocarbon models, estimating changes in exhaust hydrocarbon emissions as
a function of various fuel parameters. For Tech 4 vehicles (Model Year 1986-1995),
these models predict that as oxygen content increases from zero, with other
parameters constant, exhaust hydrocarbon (HC) will first decrease and then increase.30
According to these different models, therefore, decreasing oxygen content from a 3.5%
"no waiver" level, in the absence of other parameter changes, could either reduce or
increase exhaust HC emissions from Tech 4 vehicles, depending on the "waiver"
oxygen content. However, these HC models are a function of several parameters, i.e.,
the same parameters that are inputs to the alternative NOx models identified earlier. As
discussed and demonstrated earlier with respect to NOx, knowing only that oxygen
content is likely to decrease with a waiver, and even knowing the pool average oxygen
content with a waiver, does not provide enough information to determine the net effect
on emissions, because changes in other parameters could offset emission changes due
to oxygen. Consequently, without further information, EPA cannot predict even the
direction of the exhaust VOC emission differences between "no waiver" and "waiver"
RFC in Tech 4 vehicles.
EPA believes that the assumptions discussed earlier for Tech 3 and Tech 5 NOx
emissions are valid for Tech 3 and Tech 5 exhaust HC as well; that exhaust HC will
probably not be substantially affected by oxygen content or other parameters for Tech 5
vehicles, and the "Tech 3" exhaust HC portion of California's Phase 3 Predictive Model
may be the best available model to predict fuel-related exhaust HC changes in older
vehicles. However, this Tech 3 model requires the same fuel parameter inputs as the
alternative "Tech 4" HC models which EPA developed.
In its California analysis, EPA used Tech 3, Tech 4 and Tech 5 exhaust HC
weighting factors. As with NOx, these weighting factors were derived with California's
mobile source emissions model, and incorporated into the predictive model. The
emission weighting factors which were applied in the California analysis are California-
specific; they represent the California fleet in 2005 and were estimated using a
California-specific emission factors model. Weighting factors more applicable to the
federal fleet and/or to the New York fleet could be developed with EPA's Mobile model.
However, DEC did not submit the fuel parameter information to calculate the Tech 3 or
Tech 4 emission changes nor did it develop weighting factors for the various Tech
groups. Therefore, it is not possible, given the data submitted to make conclusions
about either the magnitude or the direction of exhaust VOC emissions from on-road
vehicles for the waiver/no-waiver comparison.
While for certain discussions, it may be useful to make a distinction between VOC
emissions and HC emissions, for purposes of the discussion here, there is no difference
between references to VOC and HC emissions. Generally speaking, we use the term HC
as the appropriate convention when referring to emissions models.
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As we did in the California analysis, EPA assumes that non-road exhaust VOC
emission changes are largely a function of oxygen content, and that exhaust VOC
emissions would increase as oxygen content decreases.31 Thus EPA would expect an
increase in non-road exhaust VOC emissions with a waiver. It would probably be
appropriate to model these emissions for New York using the factors which EPA used in
the California analysis. These factors are incorporated into EPA's NONROAD2004
model, and this model could be used directly to estimate nonroad exhaust emission
levels, in tons per day, for the RFC areas in New York in the absence of a waiver.
However, since DEC has not addressed the issue of non-oxygenated market share with
a waiver and has not provided an estimate of pool average oxygen content with a
waiver, it is not possible to estimate the magnitude of the "no waiver" to "waiver"
emission change in non-road VOC exhaust emissions.
2. Evaporative VOC emissions due to RVP increases
Non-exhaust emissions of VOC (except permeation) are modeled as a function
of RVP only.32 In other words, if estimates are available of RVP changes between the
waiver and non-waiver scenarios, existing models can be used to predict non-
permeation changes in evaporative emissions of VOC. New York has offered some
estimates of RVP changes of MTBE-containing RFC and ethanol-containing RFC. As
described earlier, this comparison is not relevant to the technical question before EPA -
whether use of ethanol-containing RFC without a waiver leads to more ozone formation
than use of RFC with an oxygen waiver. There are also other problems with New
York's assumptions.
The RVP level in ozone season RFC is tightly constrained by the need to comply
with Complex Model VOC performance standards.33 Specifically, DEC assumed that
RFC in the New York RFC area would increase in RVP by 0.3 psi if a waiver is not
granted. They attributed such increase in RVP to a regulation that EPA promulgated on
July 17, 2001 that allows a more lenient VOC performance standard (equivalent to an
increase in RVP by 0.3 psi) for RFC containing 10 volume percent ethanol. However,
this regulation applies only in Chicago and Milwaukee, and in the rulemaking EPA noted
31 Available data and models do not accommodate consideration of additional fuel
properties.
32 That is, RVP is the only fuel parameter input assumed to affect evaporative emissions.
The evaporative emission estimates produced by EPA's Mobile model are also affected
by ambient temperature inputs and other area-specific factors. In its California waiver
analysis, EPA used a formula, derived with California's EMFAC7G model, to estimate the
VOC emission differences resulting from RVP differences. It would be appropriate to use
a non-California model such as the Mobile model or the Complex model to model any
relevant RVP-related "no waiver" to "waiver" evaporative emissions changes in New York.
33 See 40 CFR 80.41 (e) and (f).
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that this limitation was needed based on the area-specific modeling used to support the
rule.34 DEC's assumptions regarding the RVP increase and associated VOC increases
are therefore in error. It is not reasonable for DEC to assume that EPA would conduct a
future rulemaking to establish a similar adjusted VOC standard for New York RFC
blended at 10 volume percent ethanol, without considering the potential impact on New
York's ozone air quality.
DEC also included estimates of a VOC emission increase predicted to occur
either statewide or just outside of RFC areas if New York granted a 1.0 psi increase in
the RVP volatility standard for ethanol-containing gasoline were granted by New York.35
There are several problems with DEC's analysis. First, DEC did not explain how the
federal oxygen content requirement for RFC relates to the use of ethanol in the
conventional gasoline used in non-RFG areas. Thus, EPA has no basis for evaluating
New York's apparent assumption that, without a waiver, ethanol will be blended into
conventional gasoline in such a way as to affect attainment of the ozone NAAQS.
Furthermore, New York itself would have to allow such a volatility waiver for
conventional gasoline. Finally, even if New York allowed the RVP of conventional
gasoline to increase, such an allowance would clearly not be applicable to RFC since
RFC is subject to other completely separate and more stringent VOC standards.
Consequently, there are flaws in New York's analysis of RVP levels to be expected in
the non-waiver scenario in both CG and RFC areas in the State. Without a more
detailed explanation of New York's argument, EPA cannot come to any conclusions
about how a 1.0 psi change in conventional gasoline might occur, how it might impact
RFC properties in the New York RFC area, and, finally, how such changes might impact
attainment of the ozone NAAQS.
As described earlier, an RVP boost and associated increase in VOC emissions
can occur within the gas tanks of cars when fuel containing ethanol is commingled with
fuel that does not contain ethanol. New York asserts that commingling will increase
when ethanol is substituted for MTBE as an oxygenate in RFC. Presumably New York
is referring to the commingling of ethanol-oxygenated RFC purchased within the New
York RFC area with non-ethanol gasolines purchased outside of the New York RFC
area. NY does not attempt to quantify this effect. While this may occur in a no-waiver
scenario, New York does not address the central question of how much ethanol-
oxygenated and non-oxygenated RFC would exist within the NY RFC area if an oxygen
content waiver were granted.
EPA believes that the maximum adverse commingling impact occurs when
ethanol and non-ethanol gasolines are sold in significant quantities in the same
34 See 66 FR 37157 and 40 CFR 80.40(c)(3).
35 New York does not allow use of the 1.0 psi RVP allowance for ethanol-containing
gasoline but can provide a waiver to blenders to use such an allowance.
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geographic area (e.g. the New York State portion of the New York City CMSA). In its
California waiver analysis, EPA concluded that this condition could exist if California
were granted an oxygen content waiver, because the refinery modeling indicated that
some refiners would blend ethanol in RFC even if the waiver was granted, while other
refiners would not. As noted previously, DEC has not addressed the issue of possible
use of ethanol in New York RFC if a waiver were granted. EPA believes that some
refiners supplying RFC to New York would blend ethanol into RFC even if a waiver was
granted, due to the octane ethanol provides and to make up for the lost gasoline volume
from MTBE resulting from New York's MTBE ban. As discussed previously, there is no
basis for EPA to assume that under a waiver, all RFC will be free of ethanol.
Consequently, the maximum adverse commingling impact could occur in New York if
EPA grants an oxygen content waiver, leading to corresponding increases in RVP and
evaporative VOC emissions. This maximum adverse commingling impact condition
would not exist in New York without a waiver, since without a waiver only ethanol-
oxygenated RFC would be sold within the New York portion of New York's RFC areas.
In summary, while some commingling could occur in the non-waiver scenario as
cars travel back and forth from New York's RFC areas (where ethanol is used) to other
areas (where it may or may not be used), such commingling would likely be much less
prevalent than would be the case with an oxygen waiver. In the absence of modeling
showing how much ethanol will be used in New York's RFC if the oxygen content
requirement were removed, EPA believes it most likely that commingling will be more
prevalent with a waiver than without a waiver. It follows that VOC evaporative
emissions resulting from commingling would likely be greater if a waiver were granted
than if it were not, however without further explanation it is not possible to estimate the
magnitude of this impact.
3. Evaporative VOC emissions due to permeation
EPA assumes that increased ethanol use would cause some increase in
permeation-related VOC emissions. DEC has provided a quantitative estimate of the
increase in emissions that could occur (6.1 tons per day over a fleet of five million
vehicles) compared to levels prior to an MTBE ban. While it provided some explanation
of the basis for this estimate, it did not specify in its January 6, 2003 submission what
this fleet represented. An enclosure to DEC'S December, 2003 submission identified
the 6.1 tons per day estimated increase as occurring in the NYCMA ozone
nonattainment area as a result of conversion from MTBE-RFG to ethanol-RFG.36 Since
ethanol may still be used in some significant quantities even if a waiver were granted,
this estimate would lead to overstating the difference in permeation VOC emissions
between the "no waiver" and "waiver" cases. EPA assumes that the "no waiver" to
oe
"Emission Impacts of Fuels to Accommodate the NY State Oxy-waiver Request and
MTBE Ban" page 6.
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"waiver" difference in permeation effect would be dependent on the amount of ethanol
used if a waiver were granted.
The change in permeation emissions between the non-waiver and waiver
conditions depends on the extent to which ethanol RFC would be used were a waiver
granted, and DEC has not provided estimates of ethanol use in RFC with a waiver.
Additionally, estimates of permeation emission changes would have to be combined
with estimates of exhaust and other evaporative VOC emission changes in order to
estimate the total "no waiver" to "waiver" VOC change. DEC has not provided such
estimates or the underlying fuel property information needed to make such estimates.
Thus, even with the best available quantitative estimate of permeation emission
differences between ethanol-oxygenated and non-ethanol gasoline, EPA could still not
determine the net effect of the oxygen waiver on VOC emissions with the information
submitted by DEC. In summary, EPA believes that permeation-related VOC emissions
would likely be less with a waiver, because we assume that less ethanol will be used
with a waiver than without. However, without further information it is not possible to
estimate the magnitude of this impact.
C. Effect of a waiver on CO emissions
DEC did not address emissions of CO, although increases in CO can contribute
to increases in ozone Because of the lack of information on ethanol market share
should a waiver be granted, there is insufficient information for a quantitative estimate of
"waiver" to "no waiver" CO emission changes for New York, since EPA cannot
determine the average oxygen content for the "no waiver" case or cases from the
available information. Directionally, EPA assumes that average oxygen content will
decrease with a waiver. CO emissions should increase for Tech 3 , Tech 4 and non-
road, and remain the same for Tech 5. While EPA can estimate this directional impact,
without further information it is not possible to estimate the magnitude of this impact.
D. Ethanol transport-related emissions
While there will be emissions resulting from the transport of ethanol to terminals,
the difference in emissions would depend, in part, on the amount of ethanol used in
New York with and without a waiver. DEC has not provided that information.
Therefore, EPA concludes that without further information it is not possible to estimate
the magnitude of this impact. In any case, Enclosure I of DEC'S January, 2003
submission suggests that the relative contribution of these emissions would be small.
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VI. CONCLUSIONS OF ERA'S ANALYSIS OF DEC'S SUBMISSION
The information that DEC has provided fails to clearly demonstrate what effect a
waiver would have an on ozone levels in New York. This is because: 1) there are three
pollutants whose emission rates could be altered by a waiver, (NOx, VOC and CO) and
all three affect ozone formation to varying degrees, 2) the lack of information on fuel
qualities with and without a waiver and the lack of other relevant and necessary
information precludes even a directional estimate of the impact of a waiver on NOx and
VOC emissions, 3) the best estimate of the net impact of a waiver on CO emissions is
that CO emissions would be greater with a waiver than without, but the difference
cannot be quantified and 4) no analysis has been provided or performed, and the
information before the agency does not allow an analysis to be performed, on the
combined effect of these emissions changes on ozone. EPA concludes that there has
been no clear demonstration as to the effect a waiver would have on ozone.37
37 The table in Appendix A summarizes EPA's qualitative consideration of New York's waiver
request.
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APPENDIX A: SUMMARY OF EPA'S ANALYSIS OF DEC'S SUBMISSION
The following table summarizes EPA's assessment of the directional change in "no
waiver" to "waiver" emissions for each on-road vehicle technology group, and for non-
road gasoline vehicles and engines. T indicates an increase, "D" a decrease, "0" little
or no change, and "?" means insufficient information to determine.
Tech 3
on-road
Tech 4
on-road
Tech 5
on-road
non-road
NOx
?
?
0
D
Exhaust
VOC
?
?
0
1
as blended
evap VOC
?
?
?
?
commingling
VOC38
lor?
lor?
lor?
lor?
Permeation
VOC
D
D
D
D
CO
1
1
0
1
38
If ethanol is used in NY's RFC to a significant extent with a waiver, then EPA expects
commingling VOC emissions to increase. If ethanol is not used extensively with a waiver,
then the direction of this VOC change is uncertain. EPA believes that significant ethanol
use with a waiver is likely.
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APPENDIX B: EPA'S RESPONSE TO DEC'S REASONS FOR NOT PROVIDING
INFORMATION THAT EPA REQUESTED
DEC provided information in its January 6, 2003 submission to EPA which we
reviewed. We responded in a letter dated April 1, 2003 with comments and questions
on the data submitted, and asked DEC to provide specific types of analyses and
information in order for EPA to evaluate New York's request for a waiver. DEC
responded to our questions in a letter to EPA dated December 12, 2003 and provided
reasons why it did not provide what we requested and in some cases why DEC felt such
information was not necessary. For those issues not discussed in the Technical
Support Document, we describe here DEC'S responses and 7 our assessment of those
responses.
I. DEC failed to provide information on the actual fuels that would likely be
used in the New York RFG area with and without a waiver
DEC states that EPA's request for refinery modeling goes beyond the scope of
the Clean Air Act as it pertains to waivers of the oxygen requirement in RFG. DEC also
states that the benefits of refinery models are questionable and that the information that
models provide is "of limited applicability" for evaluation of its waiver request. Finally,
DEC argues that because EPA commissioned its own refinery modeling study when
evaluating California's request for a waiver, that "it is more reasonable and appropriate
for EPA to perform the modeling, as New York lacks refineries or the authority to collect
specific information on their production plans."
A. Requesting refinery modeling is within the scope of the Clean Air Act
In DEC'S December 12, 2003 letter to EPA, DEC states that the refinery
modeling we requested "goes far beyond the scope of the language contained in
section 211 of the Clean Air Act and was clearly not contemplated by Congress when it
drafted section 211 (k)(2)(B) of the Act." We disagree. The Act only allows EPA to grant
a waiver if it determines that compliance with the RFG oxygenate requirement would
prevent or interfere with the attainment by the area of a national primary ambient air
quality standard. As explained in the Decision Document and the main body of this
Technical Support Document, refinery modeling is necessary for EPA to be able to
make a determination one way or another as to whether the oxygen content
requirement prevents or interferes with NAAQS attainment.
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B. DEC provides no evidence that refinery models are of limited
applicability with respect to its request for a waiver.
In its assertion that refinery models are questionable and provide information that
is of limited applicability, DEC refers to discussion of refinery modeling in the matter of
Oxygenated Fuels Association (OFA) v. Pataki, a court decision which they provided as
an attachment to their December 12, 2003 letter.39
The referenced document is a court decision in the case brought by OFA against
the State of New York. OFA claimed that New York's law prohibiting MTBE use in that
state is a violation of the Supremacy Clause of the U.S, Constitution because it
legislates in a field preempted by Congress. DEC points to the discussion of refinery
modeling in this court decision as an example of how the information provided by
refinery models is of limited applicability in DEC'S waiver application. The discussion of
refinery modeling in the referenced document does not provide such an example.
Specifically, the court rejected the evidence presented by an expert refinery
modeler based on "its lack of reliability and credibility." The expert's testimony
consisted of the results of running a refinery model comparing MTBE and ethanol-
oxygenated gasolines. Cross examination disclosed that the expert employed
undisclosed methods in preparing his report and testimony. These methods included
excluding from the expert's report model results which were unfavorable to OFA, and
using predetermined values for certain of the parameters of gasoline that affect tailpipe
emissions for MTBE-RFG but not using such predetermined values for ethanol-RFG.
Although the court discredited the expert's testimony, such action is not evidence that
the results of any and all refinery modeling is of "limited applicability," as claimed by
New York. The inappropriate withholding of modeling results or limiting variation of the
input parameters does not prove that the models themselves are inappropriate or of
limited applicability when correctly used. This fact is acknowledged in the document
that DEC included in its January 6, 2003 letter requesting a waiver-a chapter entitled
"Background and Strategies for Developing a Northeast States Oxygenate Waiver
Request" excerpted from a report prepared by the Northeast States for Coordinated Air
Use Management (NESCAUM).40 The chapter identifies arguments and data needed
for waiver requests. For each of the various arguments the document identifies for
inclusion in an application for a waiver, refinery modeling is recommended as the initial
step.
39 Oxygenated Fuels Association, Inc. v George Pataki; U.S. District court, Norther District of
New York filed Nov 24, 2003; pp. 9-13. (This document is filed in docket OAR-2003-
0004, Document II.D.6A.)
40 Filed in docket OAR-2003-0004, Document II.D.1 i.
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C. New York's lack of refineries does not prevent the State from
collecting specific information on refinery production plans
In its December 12, 2003 letter, DEC states that if EPA wishes refinery modeling
to be performed that EPA perform such modeling, because "New York lacks refineries
or the authority to collect specific information on their production plans".
Although New York State may not have the authority to collect specific refinery
information, there is a great deal of information regarding the fuel properties of gasoline
delivered to the New York area and to the Northeast generally.41 More importantly,
refinery modeling services would have to be employed in order to predict changes in the
properties of gasoline delivered to New York if a waiver were granted. Such predictions
were made by refinery modeling services for both the state of California in its waiver
request and in EPA's own analysis of those predictions. There are several widely
recognized independent refinery modeling companies that offer such services.
D. EPA's commissioning of a refinery study to evaluate California's
request for a waiver does not obligate the Agency to commission
such a study in evaluating DEC'S request
DEC argues in its December 12, 2003 letter that the precedent for EPA
conducting refinery modeling exists, pointing to EPA's commissioning a refinery
modeling study for California's waiver application.
California made available to us the following: 1) refinery modeling conducted by
Math Pro and commissioned by Chevron and Tosco42) and 2) refinery modeling
conducted by the California Energy Commission, dated December 7, 1999.43 EPA
discussed these reports and other information with California Air Resources Board
(GARB) in January of 2000. EPA concluded that the refinery modeling that GARB
provided EPA, for reasons discussed in the Technical Support Document44, did not
provide a sufficient basis for evaluation of California's waiver request. Consequently,
EPA commissioned MathPro to do additional modeling.
41 For example, the industry collects information on gasoline quality in RFC areas under the
survey requirements found at 40 CFR 80.68 and EPA regularly shares and publishes
such information and would be willing to work with New York to provide such information.
42 Available at http://www.arb.ca.gov/regact/carfg3/appo.pdf.
43 Available at
http://www.energy.ca.gOv/mtbe/documents/1999-12-07_PHASE-3^FINAL.PDFi
44 Available at http://www.epa.gov/otaq/regs/fuels/rfg/r01016.pdf
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When California requested a waiver, it was the first request for a waiver under
Section 211 (k)(2)(B) of the Clean Air Act. As such, there were no analytical precedents
for either California or EPA were able to follow. GARB diligently attempted to support its
waiver request by providing the refinery modeling that they did to EPA We felt it
appropriate that we arrange to have additional refinery modeling conducted to better
define the technical issues that we felt such analysis should address.
Therefore, our action with respect to California's waiver request was predicated
under different circumstances and does not set a precedent for similar action for New
York. Our experience with California's waiver request has now clarified the kind of
refinery modeling and comparable analyses that are appropriate to support a waiver
request. Information on the kind of modeling and analyses needed was available to New
York before it applied for a waiver, making it appropriate for EPA to expect DEC to
conduct or have conducted such analyses.
Beyond these considerations, EPA notes that it is DEC, not EPA, that seeks the
waiver. EPA believes it is appropriate to require the petitioner in such circumstances to
provide the information needed for favorable consideration of its request.
II. DEC failed to respond to our request to provide the expected changes in
emissions that would occur in a waiver and non-waiver scenario, from on-
road and non-road sources
In its initial submission, DEC only attempted to quantify emissions increases of
VOCs If a waiver was not granted, and did not provide quantitative emissions estimates
for CO or NOx for either the waiver or non-waiver scenarios. In our April 1, 2003 letter to
DEC, we asked for clarification and additional information. We requested that DEC
address the emissions (for both on-road and non-road sources) for all pollutants that
have a potential to impact a NAAQS. We requested information relating to VOC
emissions resulting from commingling and permeation effects due to ethanol with and
without a waiver. We asked specific questions about the estimates of VOC increases that
DEC made for the New York RFC area as well as upstate New York. Finally, we asked
for estimates of emission increases due to transport of ethanol to the New York RFC
area.
In its December 12, 2003 letter, DEC responded that it had considered EPA's
request for emissions modeling and that "such analyses cannot be reasonably completed
with the approved tools available - specifically the Mobile and Nonroad models." DEC
states that the emissions modeling EPA requested cannot be completed with these
models because the user inputs for the two models are different, and the nonroad model
does not model RFC at all. DEC also states: "The Mobile model does not provide for
differing the oxygenate amounts when modeling RFC, nor does it allow the user to
differentiate between oxygenate types - the very purpose of the requested modeling."
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Regarding permeation emissions, DEC stated that it included a draft paper on permeation
in its original submission. With respect to estimates of VOC due to commingling, DEC
states that such emissions are affected by a wide range of variables "that cannot be
accurately predicted with the tools available." DEC further argues that a reduction in
ethanol usage resulting from a waiver would directly reduce VOC emissions from
permeation and commingling. Finally, DEC states that the emissions modeling that it
included in its January 6, 2003 submission is accurate for purposes of the waiver
application and enclosed it again in its December 12, 2003 letter45.
A. DEC's claims that the requested emission modeling cannot be
completed are not valid.
In the attachment to EPA's April 1, 2003 letter to DEC, we stated that DEC could
use models and methods other than those referenced by DEC in its response to estimate
emission changes resulting from fuel property changes. We specifically mentioned the
model that EPA developed as part of its analysis of California's request for waiver46, and
stated that consistent with EPA's approach in its analysis of the California waiver, DEC
may use separate models and methods to estimate fuel-related emission effects in
different segments of the fleet. The referenced document also contains information on
estimating emissions from non-road sources using RFC.
We disagree with DEC's assertion that the Mobile model does not allow for
variable amounts of oxygen in the fuel. Mobile does model variable amounts of oxygen in
RFC.47 We provide advice to many states on issues such as this pertaining to the Mobile
model and are willing to do the same for New York. We note that DEC did not contact us
on this issue prior to its December 12, 2003 letter.
We also do not agree with DEC's assumption that the Mobile model does not allow
the user to differentiate between oxygenate types. Mobile does allow for such
differentiation for the reason that if ethanol is specified and the ethanol market share is
45 Filed in docket OAR-2003-0004, Document I.D.g
46 The model is discussed in Section III.A.5 of the Technical Support Document
associated with California's request for waiver (EPA-420-R-01-016, June 2001), and
which is available at http://www.epa.gov/otaq/regs/fuels/ref/r01016.pdf.
47 The FUEL PROGRAM command option 4 as a conventional gasoline program with
alternate sulfur levels can be used to provide differing inputs of oxygen. It is designed
to allow users to specify an RFC program with alternate sulfur levels, but it also allows
for varying the other non-sulfur fuel parameters through the FUEL RVP and
OXYGENATED FUELS fuel commands to approximate the non-sulfur effects of RFC.
These commands allow the user to specify the fuel RVP, the ether and ethanol market
shares, and the oxygen content of the ether and ethanol blends. Thus, if the user
wanted to keep the sulfur defaults, and was interested only in modeling RFG's with
different RVPs and oxygen content, the user would enter the default sulfur values as his
alternate sulfur values.
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not 100 percent, then Mobile slightly increases the RVP depending on market share.
Although permeation effects are not considered in Mobile, they can be estimated using
other methods.
B. DEC's reasons for not estimating commingling emissions are not
valid.
DEC asserts that the tools for estimating commingling emissions do not allow for
accurate predictions. We note that the referenced Technical Support Document for
EPA's response to California's request for waiver contains information on how
commingling emissions may be estimated.48 The variables that affect commingling
emissions allow for a range of emission changes to be estimated and evaluated as was
done for California. Increases in VOC associated with commingling are a function of the
mix of non-ethanol and ethanol-oxygenated RFC available in a given area. Some amount
of oxygenated RFC would still likely be made and supplied to the New York RFC area
even if a waiver were granted and there would also be some oxygenated RFC used in the
New York RFC area because of the adjacent areas still using MTBE-blended RFC, or
conventional gasoline. Like most models, the accuracy of a model's estimations depends
on the accuracy of the information that is used as input to the model. Refinery modeling
or comparable analysis augmented by survey data (to assess consumers "brand loyalty",
which the commingling model uses to estimate the degree of commingling that could
occur in a given area) would provide estimates of the likely mix of these two types of fuels
that refiners would supply the New York RFC area in a waiver scenario. These estimates
would then be used as inputs to the commingling model which provides a valid method to
assess the potential for emission increases due to commingling.
C. DEC's resubmitted emission estimates are in error and do not address
questions raised in our April 1, 2003 letter to them.
DEC's emission estimates that it resubmitted do not include changes in NOx and
CO emissions with and without a waiver which we asked for in our April 1, 2003 letter.
With respect to its estimates for VOCs, DEC assumes that all RFC in the New York RFC
area will be non-oxygenated in a waiver scenario. This assumption regarding the
penetration level of non-oxygenated RFC is not supported and, as described in section
IV-C of this TSD, appears likely to be faulty.
Specifically, SAE paper 940765, "In-Use Volatility Impact of Commingling Ethanol and
Non-Ethanol Fuels", by Peter J. Caffrey and Paul A. Machiele, USEPA, describes a
model developed to estimate commingling effects. Also, Dr. D. M. Rocke, University of
California at Davis, developed a probability model ("UCD model") to study commingling.
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In our April 1, 2003 letter to DEC we raised several questions regarding DEC'S
emission estimates for VOCs. Specifically, DEC assumed that RFC in the New York
RFC area would increase in RVP by 0.3 psi if a waiver is not granted. They attributed
such increase in RVP to a regulation that EPA promulgated on July 17, 2001 that allows a
more lenient VOC performance standard (equivalent to an increase in RVP by 0.3 psi) for
RFC containing 10 volume percent ethanol. Since the regulation applies only in Chicago
and Milwaukee49, DEC'S assumptions regarding the RVP increase and associated VOC
increases are in error.
DEC has not answered our questions as to why there would be statewide
increases in RVP of either 0.3 or 1.0 psi in conventional gasoline (CG) if a waiver were
not granted. With respect to the prediction of the 1.0 psi increase in RVP in CG, we
asked how the oxygen requirement for RFC (if a waiver were not granted) would result in
a level of 10 volume percent ethanol in all CG in New York State.
DEC has not responded to our request to provide an estimate of the emission
increase associated with transport of ethanol to the New York RFC area, both with and
without a waiver.
Finally, DEC also has not responded to our question regarding permeation
emissions except to say that information on this topic is limited. We asked for clarification
and explanation regarding information DEC provided in its Januarys, 2003 submission.
Specifically, DEC stated that ethanol as a replacement for MTBE will result in VOC
increases from permeation of 6.1 tons/day based on a derived emission factor applied to
five million vehicles.50 We requested DEC explain what the five million vehicles
represents; i.e., is it total vehicles in the New York RFC area, or in all of New York State?
If the latter, is it only that portion of vehicles that would use gasoline containing ethanol?
In summary, DEC asserts that its emissions modeling for VOCs is accurate, but
EPA has identified certain shortcomings in New York's approach, and has asked several
questions (which DEC has chosen not to answer) that need to be answered for EPA to
ascertain whether or not other shortcomings exist.
49 See 66 FR 37157 and 40 CFR 80.40(c)(3)
50 Filed in docket OAR-2003-0004, Document II.D.1 h.
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III. EPA's issuance of an enforcement discretion letter does not preclude the
granting of an oxygenate waiver
In its December 12, 2003 letter, DEC references an enforcement discretion letter
from EPA to the American Petroleum Institute.51 DEC asserts that EPA through this
enforcement discretion "has enacted a requirement for fuels containing 10 percent
ethanol" and that such action precludes the granting of an oxygen content waiver.
The referenced letter does not constitute a requirement that fuels in the New York
RFC Area contain 10 percent ethanol. In fact, the enforcement discretion letter does not
preclude the use by refiners of oxygenates other than ethanol or, if EPA were to grant
New York's waiver request, the delivery of RFC with no oxygenate. The enforcement
discretion letter simply informs parties that receive reformulated gasoline blendstock for
oxygenate blending (RBOB) at terminals and blend 10 volume % ethanol to produce RFC
of a set of circumstances under which their RBOB will be treated as certified under 40
C.F.R. Section 80.69(a)(2). It does not require that all RFC in the New York RFC area
contain any quantity of ethanol, and does not preclude the granting of an oxygen content
waiver.
51 Letter dated December 3, 2003 from John Peter Suarez, Assistant Administrator of the
Office of Enforcement and Compliance Assistance, to Edward H. Murphy, American
Petroleum Institute.
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