1 DRAFT

Memorandum

From: Brian Timin , Air Quality Modeling Group, Office of Air Quality Planning and Standards,

EPA

To: Docket ID No. EPA

- HQ

- OAR

- 2011

- 0729: Regional Haze: Revisions to Provisions Governing Alternatives to Source

- Specific Best Available Retrofit technology (BART) Determinations, Limited SIP Disapprovals, and Federal Implementation Plans

Re: Sensitivity Analysis Accounting for Increases in Texas and Georgia Transport Rule State Budgets

The Better than BART modeling analysis for th e proposed rule and final rule was completed using the emissions totals from the final Transport Rule, and also assuming that the July 11, 2011 proposal regarding ozone

- season NOx emissions in five states would be finalized. 1 In addition to the changes in the July 11, 2011 supplemental notice there have been subsequent adjustments to state budgets. On February 21, 2012, the EPA published revisions to 2012 and 2104 state budgets in Arkansas, Georgia, Indiana, Kansas, Louisiana, Mississippi, Missouri, New Yor k, Nebraska, Ohio, Oklahoma, South Carolina, and Texas, along with revisions to new unit set

asides in Arkansas, Louisiana, and Missouri. 2 In all cases, the budgets were increased. The analysis presented in this memorandum represents the EPA’s evaluation o f the potential impact of the full suite of Transport Rule revisions as presented in both Transport Rule actions published in February 2012. Table 1 summarizes the sums of the final (77 FR 10324) and proposed (77 FR 10350) budget increases.

Overall, the S O 2 and NOx budget increases are relatively modest compared to the total modeled reductions from the Transport Rule. The modeled SO 2 reductions from the Transport Rule are ~3.8 million tons per year and NOx reductions are ~125,000 tons per year. After consi dering the

SO 2 budget increases, the “Transport Rule +BART

- elsewhere” control scenario is still projected

to result in ~3.7 million tons per year of SO2 reductions, which is 773,000 tons more emission

reductions than “nationwide BART”. The NOx budget incr eases are projected to result in the “nationwide BART” scenario achieving about 8,000 tons more emission reductions than the “Transport Rule + BART

- elsewhere” control scenario. However, since the visibility improvements attributable to the “Transport Rule + BART

- elsewhere” scenario are due primarily to the large emission reductions in SO 2 over the T ransport Rule region, the increases in SO 2

1 The air quality modeling conducted for this analysis included in the CSAPR scenario the states addressed in the July 11, 2011 proposal. These states are Iowa, Kansas, Michigan, Nebraska, Minnesota, and Oklahoma. This supplemental notice was finalized in De cember 2011. 76 FR 80760.

2 77 FR 10342 and 77 FR 10350. Some of these Transport Rule revisions were published in a final rule, whereas others were published in a direct final rule with parallel proposal. The EPA received adverse comments on the parallel proposal and subsequently withdrew the direct final rule. After reviewing comments on the parallel proposal, the EPA plans to finalize its proposal as expeditiously as possible. The analysis in this memo confirms that the Transport Rule satisfies the bett er

- than

- BART test if the state

- by

- state budgets are no higher than would be the case if EPA finalizes the parallel proposal as proposed.2 emissions are most likely to affect the Transport Rule as an alternative to BART analysis. The SO2 increases from Georgia and Texas (shown in Table 1) make up the majority of the SO2 increases (~70%) from the Transport Rule revision rules. Due to the dominance of sulfate impacts on visibility 3 in both the Transport Rule and BART cases, and the relatively large SO2 budget increases in Texas and Georgia, we completed a more detailed sensitivity analysis of the potential impacts from the Texas and Georgia SO 2 budget increases.

Table 1

. I ncreases in Transport Rule 2014 SO 2 and NOx budgets.

State 2014 SO 2 Budget Increase (tons) 2014 NOx Budget Increase (tons)

Louisiana N/A 4,683
Mississippi N/A 2,269

Michigan N/A 5,228

Nebraska 3,110 3,559

New Jersey N/A 679

New York 8,971 4,179

Texas 50,157 4,106

Wisconsin 7,757 2,473

South Carolina 8,013 N/A

Indiana 5,338 N/A

Ohio 5,163 2,765

Kansas 452 5,794

Georgia 40,334 13,198

Missouri N/A 26

Oklahoma N/A 859

Total Increase 129,295 49,818

Table 2 shows the Texas and Georgia SO 2 emissions as modeled (i.e., with trading) in the Better than BART analysis and the emissions that would occur if the state budgets are increased as proposed assuming that all of the additional allowances are used by sources in the res pective state (i.e., we did not re

- model trading).

3 For the 16 Class I areas examined in this analysis, the change in light extinction in the 2014 Transport Rule +

BART elsewhere case due only to sulfate ranged from 96

- 121% of the total change in light e xtinction on the 20% worst days and 80

- 150% of total change in light extinction on the 20% best days. The fraction of visibility change

attribut able to sulfate can be gr eater than 100% of the total change in extinction because there is often a large decrease in sulfate extinction and a simultaneous increase in nitrate extinction (due to nitrate replacement). This shows the dominant nature of the impact of SO 2 emissions r eductions on the overall visibility results, especially at the Class I areas most affected by Texas and Georgia.3 Table 2

. Texas and Georgia 2014 SO 2 emissions and decreases compared to the 2014 modeled

base case

. 2014 Base Case

SO 2 Emissions 2014 TR+

BART

elsewhere

SO 2 Emissions (estimate

from IPM

used in air

quality modeling) SO 2 Emissions

Decrease

from TR (as modeled) 2014 Budget

Increase SO 2 Emissions

Decrease from TR

with Increased Budget

Texas 453,332 266,627

- 186,705 50,157

- 136,548 Georgia 170,300 93,600

- 76,700 40,334

- 36,366

Total 623,632 360,227

- 263,405 90,491

- 172,914

Table 2 shows that the modeled SO 2 reductions in Texas and Georgia are ~264,000 tons per year. After accounting for the proposed increase in the SO 2 budget for Texas and Georgia, the SO 2 emissions reduction is still ~173,000 tons per year. This would reduce the total SO 2 reduction from the Transport Rule from ~3.8 million tons per year to ~3.7 million tons per year.

It can be seen from Table 2 that even with the increase in the SO 2 budgets for Texas and Georgia

there is still a large SO 2 reduction in Texas and Georgia, compared to the 2014 base case and the impact on the total net SO 2 reduction from the Transport Rule is minimal (~2.4% decrease in total Transport Rule region SO 2 reductions).

Given this information, we would still expect major visibility improvements at Class I areas in and around Texas and Georgia from the Transport Rule. However, in order to better account for the potential visibility impacts from the budget revisions, we per formed a very conservative sensitivity analysis to provide an upper estimate of the worst case impacts to visibility due to increases in Texas and Georgia SO 2 budgets.

Sensitivity Analysis of Better than BART with Increased Texas and Georgia SO 2 Allowances

We identified the most likely “affected” Class I areas for Texas and Georgia and then assumed that these areas would get less than the full modeled benefit from the Transport Rule. Table 3

shows the nine Class I areas in and near Texas that w ere identified as the affected areas. 4

4 Affected Class I areas were identified by examining consultation letters from Texas to states surrounding Texas

which were included in the Texas regional haze SIP submissions. These letters were based on the CENRAP analysis. The letters are included in Appendix 4

- 3 available here: We identified these areas by looking at the regional haze analysis conducted by the CENRAP regional planning organization in support of the development of regional haze SIPs in Texas and

http://www.tceq.texas.gov /airquality/sip/bart/haze_appendices.html . We included six areas which had a > 2 Mm

- 1
impact from Texas. These areas had much higher visibility impacts from Texas compared to other analyzed Class I

areas. We also included the three Class I areas that ar e in Texas or are represented by an IMPROVE monitor that is

located in Texas.4 surrounding states.

Table 3

. Class I areas most affected by Texas emissions and the modeled visibility improvement from the Transport Rule + BART

- elsewhere case

.

Class I Area Name State TR+BART

elsewhere 20% Best days TR+BART

elsewhere 20%

Worst days
Big Bend NP TX

- 0.2

- 1.1
Caney Creek Wilderness AR

- 0.4

- 3.2

Carlsbad Caverns NP TX

- 0.1

- 0.9
Guadalupe Mountains NP TX

- 0.1

- 0.9

Hercules

- Glades Wilderness MO

- 0.6

- 2.5

Salt Creek NM

- 0.1

- 0.7
Upper Buffalo Wilderness AR

- 0.5

- 2.5

White Mountain Wilderness NM

- 0.1

- 0.6

Wichita Mountains OK

- 0.2

- 1.6

Table 4 shows the seven Class I areas in and near Georgia that were identified as the affected

areas. 5 We identified these areas by looking at the regional haze analysis conducted by the VISTAS regional planning organization in support of the development of regional haze SIPs in Georgia and surrounding states.

Table 4

. Class I areas most affected by Georgia emissions and the modeled visibility improvement from the Transport Rule + BART

- elsewhere case

.

Class I Area Name State TR+BART

elsewhere

20% Best days TR+BART

elsewhere 20%

Worst days

Cohutta Wilderness GA

- 0.8

- 3.8
Great Smoky Mountains NP TN

- 0.8

- 3.7

Joyce

- Kilmer

- Slickrock Wilderness TN

- 0.8

- 3.7

Okefenokee GA

- 0.9

- 2.5
Shining Rock Wilderness NC

- 0.7

- 3.8
Sipsey Wilderness AL

- 0.9

- 3.7

Wolf Island GA

- 0.9

- 2.5

5 Affected Class I areas were identified by reviewing the results of the VISTAS consultation process. This process is summarized in Chapter 10 of the Georgia SIP, which is availa ble at http://www.gaepd.org/Files_PDF/plans/sip/Narr_061009.pdf (accessed May 2, 2012). We included four areas outside of Georgia where EGUs whose allocation increased was identified as contributing more than 0.5% to visibility impairment. We also included the three Class I areas that are in Georgia.5 For this analysis, we assumed that the visibility benefits shown in Tables 3 and 4 would be proportionally reduced as a result of the allowance adjustments for SO 2 in Texas and Georgia.

The SO 2 allowance increases in Georgia cause a 52% reduction in the number of SO 2 tons reduced compared to the proposal modeling, therefore we m ultiplied the visibility improvement at the Class I areas affected by Georgia by a factor of 0.48. The SO 2 allowance increases in

Texas cause a 27% reduction in the number of SO 2 tons reduced compared to the proposal modeling. Therefore we multiplied the v isibility improvement at the Class I areas affected by Texas by a factor of 0.73. This assumes that the 52% and 27% reduction in SO 2 emissions reductions in Georgia and Texas respectively will linearly reduce the visibility benefits in nearby

Class I areas by 52% and 27%.

The methodology employed is very conservative because we assume that all of the visibility improvement from the Class I areas affected by Texas and Georgia are solely due to emissions from Texas and Georgia respectively. This is an especi ally conservative assumption for the Class I areas affected by Georgia because there are over 1 million tons of SO2 reductions from the Transport Rule in the nearby states of Alabama, North Carolina, South Carolina, Tennessee, Virginia, and Kentucky. Emiss ions reductions from these states would also affect the Class I areas identified as being affected by Georgia. But in this analysis we assume that only Georgia impacts these areas.

As shown in Table 1 there are additional states that have smaller SO 2 and NOx allowance increases. However we believe the conservative nature of this analysis more than offsets any small impact from other states. We therefore believe it is appropriate to limit the analysis to Texas and Georgia.

Sensitivity Analysis Results

W e recalculated the average visibility changes at the 60 Eastern and 140 nationwide Class I areas in the Better than BART analysis, using the adjusted visibility change at the 16 Class I areas in Tables 3 and 4. The first prong of the Better than BART test is still passed because there will be no degradation in visibility at any Class I areas on either the 20% best or 20% worst days. Table 5 below shows the average visibility results and the re

- calculated average visibility results for the sensitivity case.6 Table 5. Average visibility improvement on the 20% best and 20% worst days in the Better than BART analysis and the Texas and Georgia sensitivity analysis.

“Transport Rule +

BART

elsewhere” “Transport Rule +

BART

- elsewhere”

Texas/Georgia Sensitivity Case “Nationwide BART”

60 Class I Areas in the Eastern Transport Rule Modeling

Domain

20 percent Worst Days 1.6 1.3 1.0

20 percent Best Days 0.3 0.2 0.2

140 Class I Areas in the Western and Eastern Transport Rule Modeling Domains

20 percent Worst Days 0.7 0.6 0.5

20 percent Best Days 0.1 0.1 0.1

Table 5 shows that the even with the conservative assumptions in this analysis, the Transport

Rule+ BART

- elsewhere case is still, on average, better than (or equal to) nationwide BART on both the 20% best and 20% worst days at the 60 Eastern Class I areas and at the 140 nationwide

Class I areas.