1 

## Appendix 3.1

Responsiveness Summary

During the public comment period, the NDEQ received comments from the following interested parties:

United States Environmental Protection Agency

– Region 7

State of Colorado

– Department of Public Health and Environme nt, Air Division United States Department of the Interior

– Air Resources Division United States Department of Agriculture

– Forest Service

Twin Platte Natural Resources District

National Parks Conservation Association

The following paragraphs summarize the comment s received. Where appropriate, comments

have been combine d and responses consolidated. Any c hanges to the SIP document have been clearly identified in this summary document.

Comment 1: Interstate Consultation

The US Environmental Protection Agency

- Region VII (EPA) asked that NDEQ provide

confirmation that SO 2 reductions are no longer needed from the Nebraska sources in order to achieve visibility goals in nearby S tates that host Class I areas and that NDEQ address the

differences between the assumptions made by the states in estimating the visibility improvement needed to meet their reasonable progress goals (RPGs) and what is actually being proposed in the NDEQ State Implementation Plan.

Response to Comment 1: NDEQ consulted with nearby sta tes that host Class I areas at two important points during our SIP development process outside of the CENRAP process. First, because we understood that the BART determinations were different than what they may have been expecting for reductions

from Nebra ska, we provided an opportunity to comment on the BART permits for both OPPD NCS and NPPD GGS. The state of Colorado provided comments on the NPPD GGS permit for

Nebraska to consider , which we evaluated. The second opportunity was during the proposal of

t he SIP. The state of Colorado provided further comment for NDEQ to consider. Those comments are addressed in this summary. No other states have provided comment or feedback. NDEQ thinks that it would be most appropriate to address whether nearby states are meeting their reasonable progress goals and whether additional measures are needed from Nebraska sources during the periodic reviews of the SIPs.

Comment 2: Significance of Visibility Improvement as a Metric

The EPA made comments related to the use of a significance threshold. EPA noted that NDEQ argued that SO 2 controls were not being required at Omaha Public Power District Nebraska City Station (NCS) and Nebraska Public Power District‟s GGS Station (GGS) in part because the visibility improvement gained by SO 2 control at those facilities is not significan t enough to
warrant the cost of control. EPA is requesting explanation of the criteria used to determine significance (ex. single threshold, number of days the threshold can be exceeded, percent change2

in improvement, or comparison of the number of days where the threshold is exceeded). The EPA also asked how the significance of the visibility improvement does or does not justify the

level of control in the context of the BART determinations and the overall Long Term Strategy

.

Colorado commented on a similar issue with regard to the NPPD GGS NOx control analysis. They provided an example of how they determined significance. Colorado believed that LNB

with OFA and SCR is cost effective given the tonnage of NOx reduced. Colorado used a NOx control cost criteria of <$5,000 per ton along with visibility improvement of 0.5 dv to inform the appropriateness of SCR controls.

Response to Comment 2: NDEQ agre es with EPA that a discussion regarding the decision making process should be included in the SIP. In preamble of the final Regional Haze Rule and BART Guidelines (July 6, 2005), EPA discusses the flexibility provided to states in establishing such criter ia for making

such decisions:

“Because each Class I area is unique, we believe States should have flexibility to assess visibility improvements due to BART controls by one or more methods, or by a combination of methods, and we agree with the commenters s uggestions to do so. We believe the maximum 24hour modeled impact can be an appropriate measure in determining the degree of visibility improvement expected from BART reductions (or for BART applicability). We have pointed out; however, that States should have flexibility when evaluating the fifth statutory factor. A State is encouraged to account for the magnitude, frequency, and duration of the contributions to visibility impairment caused by the source based on the natural variability of meteorology. Th ese are important elements to consider as they would provide useful information on both the short term peak impact and long term average assessments which are critical in making the visibility

assessment.

We agree with the suggestion that the use of a com parison threshold, as done for determining if

BART

- eligible sources should be subject to a BART determination, is an appropriate way to evaluate visibility improvement. However, we believe the States have flexibility in setting absolute thresholds, target levels of improvement, or de minimis levels since the deciview improvement must be weighed among the five factors, and States are free to determine the weight and significance to be assigned to each factor. For example, a 0.3, 0.5, or even 1.0 deciview imp rovement may merit stronger weighting in one case versus another, so one „„bright line‟‟ may not be appropriate.

In addition, comparison thresholds can be used in a number of ways in evaluating visibility improvement (e.g. the number of days or hours that the threshold was exceeded, a single threshold for determining whether a change in impacts is significant, a threshold representing an x percent change in improvement, etc.) Other ways that visibility improvement may be assessed

to inform the control dec isions would be to examine distributions of the daily impacts, determine if the time of year is important (e.g. high impacts are occurring during tourist season),

consideration of the cost

- effectiveness of visibility improvements (i.e. the cost per change in deciview), using the measures of deciview improvement identified by the State, or simply compare the worst case days for the pre

- and post

- control runs. States may develop other methods

as well. ”3

NDEQ added a general discussion to Section 10.4 describ ing the factors that informed the process and summaries in Sections 10.5 and 10.6 explaining how each source fit into that

process.

NDEQ also us ed a $5,000 incremental cost per ton threshold for determining cost effectiveness

for incremental costs for S CR.

Comment 3: Use of the $/deciview ($/ dv ) EPA has concerns with NDEQ‟s use of the $/ dv metric as follows: Although the BART rules allow for States to use a $/ dv metric in evaluating cost effectiveness, EPA is concerned that NDEQ is using this as the s ole factor in making the

BART determination.
EPA believes that the $/ dv metric is less meaningful because it does not take into account visibility impacts at multiple Class I areas or ignores the total improvement. EPA contends that it only accounts for t he “worst day” of improvement scenario instead of taking into consideration multiple days of improvement.
EPA believes the $/ dv metric would be more meaningful if put into the context of significance of visibility improvement. The United States Forest Ser vice (USFS) also provided this same comment. The USFS believes the $/ dv should consider the total visibility benefit across multiple Class I areas.

EPA provided a list of BART sources from Oregon, Wyoming, North Dakota, and South Dakota along with the B ART cost information, visibility improvement and their $/ dv analysis to put it into perspective

.

The NCPA and FLMs raised concerns with using cost per deciview a s a metric of cost

effectiveness

. They believe there are several flaws in the use of this metric in NDEQ‟s BART

determinations. First, incremental cost per deciview is almost exclusively emphasized as a metric of cost effectiveness. The total cost per deciview, instead, should be used as a supplement to cost per ton as a means of evaluating c ost

- effectiveness. Second, the fact that the potential control efficiency of the technologies evaluated is routinely underestimated (see above) will also lead to underestimated benefits as far as deciview reduction (visibility improvement). Third, as

descr ibed below, costs are overestimated. The combination of overestimated costs and underestimated visibility improvement means that the cost per deciview metric is routinely (and significantly) inflated in NDEQ‟s calculation. All of the cost per deciview valu es cited by the draft BART determinations should be reevaluated and appropriately revised.

Fourth, the cost per deciview metric is more appropriately evaluated in the context of the total improvement that the control measure is responsible for. Thus, it should take into account the cumulative benefit over all relevant Class I areas, not simply the most heavily impacted one. Additionally, the total improvement as far as frequency, magnitude, and duration of visibility changes should be taken into account w hen comparing cost per deciview metrics.

Finally, once an accurate cost per deciview value is established, it can be compared to cost per deciview measures from other BART determinations. Around the country, proposed BART determinations have exceeded $50 million, with averages in the $14

- 18 million range. Based on4

the issues listed above, we ask that NDEQ reevaluate the benefits associated with the control technologies proposed in its BART determinations, rerun modeling to reflect the higher levels of

co ntrol that are achievable, and recalculate total cost effectiveness measures based on accurate

cost estimates.

Response to Comment 3 : NDEQ understands the concerns raised and believes that the response to Comment 2 along with changes to the SIP document a ddresses the concern s raised

.

Additionally, NDEQ would like to clearly state that it did not rely solely on one factor in making

its BART determination s , but rather, considered all of the statutory factors. Furthermore, the EPA‟s citation of the $/ dv me tric as only one factor is mistaken, since by definition, this

calculated ratio includes both the cost and the benefit (degree of visibility improvement). The

other factors (the energy and non

- air quality environmental impacts of compliance, any existing pollution control technology in use at the source, and the remaining useful life of the source) were also considered in the analysis. Therefore, Nebraska has indeed considered all factors and has not relied on a single factor in its BART determination s

.

T he Clean Air Act, Section 169A (g) (2) states: “in determining best available retrofit technology the State (or the Administrator in determining emission limitations which reflect such technology) shall take into consideration the costs of compliance, the energy and non

- air quality environmental impacts of compliance, any existing pollution control technology in use at the source, the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be anticipated to resu lt from the use of such technology”

EPA‟s initial Regional Haze rules had directed states to set BART emissions limits based on only the first four factors listed in the above statutory language, after determining that a given source was “subject” to BART . Thus, EPA had initially left the visibility improvement factor out the BART determination step. In the case of American Corn Growers Assn v. EPA (291 F.3d 1; D.C. Cir., 2002), the court sided with the American Corn Growers Association, and ruled that all five factors, including the “degree of visibility improvement” needed to be considered in the BART determination. EPA subsequently revised the Regional Haze rules accordingly, on July 6,

2005. In the preamble, EPA clearly provides discretion to states:

“As we noted in 2004, this estimate of visibility improvement does not by itself dictate the level of control a State would impose on a source; „„the degree of improvement in visibility which may reasonably be anticipated to result from the use of [BART] ‟‟ is only one of five criteria that the State must consider together in making a BART determination. The State makes a BART determination based on the estimates available for each criterion, and as the CAA does not specify how the State should take these factors into account; the States are free to determine the weight and significance to be assigned to each factor... we believe the States have flexibility in setting absolute thresholds, target levels of improvement, or de minimis levels since the deciview

im provement must be weighed among the five factors, and States are free to determine the weight and significance to be assigned to each factor. For example, a 0.3, 0.5, or even 1.0 deciview improvement may merit stronger weighting in one case versus another, so one „„bright line‟‟ may not be appropriate. ”5

NDEQ evaluated all the factors and made its determination based upon taking each one into

careful consideration. It is clear from the guidance provided in the preamble that decisions on

BART were left to t he States and that when making such decisions, individual circumstances can and should be taken into account. It is impractical for EPA to take such individual circumstances into account when developing a national rule that is the reason for State discret ion to account for unique or special circumstances, such as: lack of attrib ution to a distant Class I area, significantly increased solid waste disposal requirements, and constraints on obtain ing new water due to local restrictions, state law, moratoriums, multi

- state compacts, and federal agreements.

NDEQ also evaluated the information pro vided by EPA regarding the BART determinations in

several other states. The evaluation was done to determine whether other states utilized the $/ dv

metric in a manner contrary or comparable to Nebraska. NDEQ evaluated the benefit at the closest Class I areas, consistent with the Regional Haze rule, which were still >300 km away from the sources. NDEQ reviewed the proposed SIPs of the other states, to determine whether the metric NDEQ used was consistent with that of the other states. NDEQ found that the $/ dv methodology utilized by NDEQ appeared to be consistent with that of the states in the table. NDEQ also found that the $/dv were significantly higher for the Nebra ska sources than those of the other states. NDEQ attributes this difference to one of two reasons 1) sources being closer to Class I areas and thus having more impact/benefit or 2) cost to retrofit the source being lower

than that of the Nebraska sources. The table detailing the comparison, Table 10.19, was added to

Section 10.6.4.10

.

Comment 4 : Control Efficiencies

EPA commented that NDEQ should evaluate feasible control technologies using the most reasonable control efficiency possible. They went on to state that it is their experience flue gas desulfurization units can operate as low as 0.02 lb SO 2 /MMBtu

.

The National Parks Conservation Association (NPCA) out of Knoxville, TN and Plains Justice (PJ) out of Billings, MT submitted a joint comment letter regarding the adequac y of the BART

determinations

. The NPCA/PJ believe that NDEQ did not follow the BART guidelines or otherwise meet the intent of the BART requirements because it did not evaluate the most stringent option available for reducin g emissions from the state‟s EGUs from technologies such as Selective Catalytic Reduction and wet and dry scrubbers.

They state that the NDEQ‟s evaluations assumed that SCR is capable of achieving 0.08

lbs/mmbtu NO

x . In reality, SCRs are being permitted at and can achieve levels of 0.05 lbs/mmbtu or less on an annual basis and 0.06 lbs/mmbtu on a 30 day rolling average. 0.08 lbs/mmbtu reflects no more than 83% reduction from current emissions; SCR is well known to be capable of control efficiency greater than 90%.

Their review of recent SCR retrofits at other power plants they believe definitively proves that very high levels of NO

x removal are being achieved by recent SCR retrofit installations. NO

x emission rates less than 0.05 lb/ MMBtu are routinely a chieved, and NO

x removal efficiencies are typically a t least 90%. Permitting agencies have required lower NO

x limits in recent BACT determinations, with many proposed and required BACT limits of 0.05

- 0.06 lb/MMBtu. For example, the Plant Washington PSD pe rmit, issued in April 2010, requires that unit to meet a6

0.03 lb/MMBtu annual average NO

x limit as BACT. The Desert Rock PSD permit includes a

NO

x BACT limit as low as 0.035 lb/MMBtu.

Likewise, the NPCA/PJ and USFS believe that NDEQ BART determinations un derestimate the

emissions levels achieved with SO 2 controls, assuming control efficiencies no more than 87% and corresponding emission levels between 0.1

– 0.15 lbs/mmbtu. However, modern SO 2 controls are capable of reducing emissions by more than 99% to less than 0.04

– 0.06 lbs/mmbtu, depending on the technology.

In addition, they believe the state provided no evidence that the emission levels set in association

with the use of Low NO

x Burners/Overfire Air (LNB/OFA) or each facility‟s existing particula te matter controls actually reflect the most efficient use of the technology, rather than simply presumptive BART (0.23 lbs/mmbtu) in the case of NO

x and LNB/OFA, or the existing permit limits (0.10 lbs/mmbtu) in the case of PM and existing baghouses or el ectrostatic precipitators. At a minimum, they believe these limits should be set with knowledge of what current emission levels are being achieved as well as what emission levels have been achieved elsewhere.

Response to Comment 4 : States must identify th e “ best ” system of continuous emission control technology for each source subject to BART taking into account the technology available, the costs of compliance, the energy and non

- air quality environmental impacts of compliance, any pollution control equip ment in use at the source, the remaining useful life of the source, and the degree of visibility improvement that may be expected from available control technology. NDEQ believes that EPA does not mean that a “maximum” level of control must be evaluated, but that when considering all of the factors, the State must select the best alternative for control, given the

individual circumstances.

In the preamble to the final rule, EPA speaks to the issue of the level of emission control:

“ We received a few comm ents expressing the belief that the presumptive limits should be more stringent, given that BART emission limits will not be fully implemented until 2013 or 2014. We recognize that while some scrubber units currently achieve reductions greater than 95

perc ent, not all units can do so (emphasis added). The individual units that currently achieve greater than 95 percent control efficiencies do not necessarily represent the wide range of unit types across the universe of BART

- eligible sources. An analysis of t he Department of Energy‟s U.S. FGD Installation Database supports our belief that 95 percent removal efficiencies would be obtainable by all types of EGUs burning medium and high sulfur coal by 2014, including

BART

- eligible EGUs. In addition, we note that the presumption does not limit the States‟ ability to consider whether a different level of control is appropriate in a particular case. If, upon examination of an individual EGU, a State determines that a different emission limit is appropriate based upon its analysis of the five factors, then the State may apply a more or less stringent limit (emphasis added) .”

It is difficult to ascertain the maximum efficiency the technology could achieve at the source until it is installed and optimized. However, NDE Q believes the point is to have the State consider other possible efficiencies the technology could achieve when determining whether something is cost effective. NDEQ did consider a lower lb/MMBtu than the presumptive level.7

To determine whether the level s at which NDEQ evaluat ed were appropriate for SO 2 control, NDEQ retrieved data from the EPA database to determine how existing FGD systems performed at existing sub

- bituminous coal fired EGUs. While units were found that performed at or below

0.1 lb/MMBtu , NDEQ did not find where levels as low as 0.02 lb/MMBtu were being met , and several did not meet the 0.15 lb/MMBtu presumptive level. See table below.

2 009 SO 2 Emissions & Controls on Electric Generation Units

State Plant Name Unit SO 2 TPY SO 2 lb/MMBtu B oiler Type SO 2 Controls

CO Craig C1 1

, 083.3 0.0615 Dry bottom Wet Limestone

CO Craig C2 1

, 125.5 0.0638 Dry bottom Wet Limestone

CO Craig C3 1

, 686.3 0.1161 Dry bottom Dry Lime FGD

CO Rawhide Energy Station 101 1

, 060.8 0.0875 Tangentially

- fired Dry Lime FGD

KS Holcomb SGU1 1

, 948.3 0.1413 Dry bottom Dry Lime FGD

KS Jeffrey Energy

Center 1 653.2 0.0280 Tangentially

- fired Wet Limestone

KS Jeffrey Energy

Center 2 4

, 092.6 0.1790 Tangentially

- fired Wet Limestone (Began Apr 01, 2009)

KS Jeffrey Energy

Center 3 1

, 286.9 0.0506 Tangentially

- fired Wet Limestone

KS La Cygne 1 5

, 085.6 0.2022 Cyclone boiler Wet Limestone

KS La Cygne 2 16

, 243.4 0.7160 Dry bottom

MN Sherburne County 1 6

, 583.7 0.2635 Tangentially

- fired Wet Limestone

MN Sherburne County 2 6

, 385.9 0 .2631 Tangentially

- fired Wet Limestone

MN Sherburne County 3 11

, 046.2 0.3317 Dry bottom Dry Lime FGD

MO Hawthorn 5A 2

, 016.0 0.0948 Dry bottom Dry Lime FGD

ND Stanton 1 2

, 188.6 0.5333 Dry bottom

ND Stanton 10 152.5 0.0693 Tangentially

- fired Dry Lime FG D

OK Grand River Dam Authority 1 13

, 443.5 0.7313 Dry bottom N/A

OK Grand River Dam Authority 2 4

, 569.4 0.1978 Dry bottom Dry Lime FGD

OR Boardman 1SG 11

, 056.9 0.7018 Dry bottom N/A

WY Dave Johnston BW41 3

, 681.0 0.7657 Dry bottom N/A

WY Dave Johnston B W42 3,627.0 0.7736 Dry bottom N/A

WY Dave Johnston BW4 3 7

, 177.7 0.7588 Cell burner boiler N/A

WY Dave Johnston BW44 3

, 291. 7 0.3293 Tangentially

- fired Other

WY Neil Simpson II 1 555.7 7 0.1382 Dry bottom Dry Lime FGD

WY Wygen I 1 568. 3 0.1306 Dry bottom Dry Lime FGD

WY Wyodak BW91 7

, 436. 9 0.4694 Dry bottom Dry Lime FGD

Note : The lbs/ MMBTU was figured by dividing the annual SO 2 tons values by the annual MMBTU values. NDEQ recognizes that

short term periods (30 day) may show lower o r high values.8

The ta ble above shows has many sources not been able to meet the presumptive levels of BART (0.15 lb/MMBtu) for SO 2 control over a 12

- month period . Evaluating a 0.1 lb/MMBtu level seemed to be a reasonable, yet aggressive level of control. Furthermore, while requiring a lower level of control, down to 0.02 lb/MMBtu would result in lower levels of emissions, it is likely more water and more lime would be required, increasing the costs of operating and possibly to install a scrubber to properly size for such lev els of control. Therefore, it does not automatically follow that the cost effectiveness would make the project more reasonable.

Comment 5 : Water Resources

EPA commented that the BART determination should include a discussion as to whether stressed

wate r resources are truly unique to the State of Nebraska, for purposes of visibility protection, and whether the visibility improvement meets the State‟s threshold of significance. EPA states that the arguments raised by NDEQ regarding water resources were m ore grounded in costs, not uniqueness or feasibility.

Other commenters suggested that scrubbing was still cost effective despite the costs outlined in the proposed SIP. Other comments raised questions regarding the assumptions made in the impacts to th e water resources of the state.

The United States Forest Service ( USFS ) submitted comments regarding the statement made in the SIP about Nebraska‟s obligation to the Platte River Recovery Implementation Program (PRRIP). A review by the Nebraska Field of fice was done. The Field Office was asked to review and provide an opinion on: 1) the merit of NDEQ arguments and 2) any options for utilizing water while maintaining Endangered Species Act (ESA) protection.

The USFS concluded that the arguments , statem ents about Nebraska water law, and the ensuing

commitments Nebraska has under the PRRIP presented by Nebraska in the SIP are accurate and have merit, but may represent a worst

- case scenario. They believe that the PRRIP inherently provides options to offse t consumptive use that results in depletions to the river and jeopardizes endangered species. They believe that while, not inaccurate, the information tends to overstate implications of any new water use by NPPD.

The USFS Field Office noted that achie ving the ESA recovery objectives of the PRRIP will be a challenging endeavor and it is in the Service‟s interests to see Nebraska succeed. However, they believe that the figures and calculations used to describe offset needs and the comparison used

when ev aluating the offset versus other needs/obligations may portray a worst

- case scenario. First, offset needs for the PRRIP and Integrated Management Plans (IMPs) may be able to be met concurrently or synergistically. The y say the SIP fails to note that the majority of the remaining 50,000

- 70,000 Acre Feet (AF) of PRRIP 1 st Increment water objective will likely be met by re

- timing (re

- regulating) existing water supply from times when target flows are exceeded to times of shortage (i.e. not solely by obtainin g “new” water via conservation or acquisition of existing water rights ). Further, any commitment of the parties to proceed toward obtaining the estimates of water listed for a 2nd and 3rd Increment is speculative, at best. While

the Service has calculated an average annual shortage to targets of approximately 430,000 AF, there is no certainty that future PRRIP increments will include an objective to achieve this magnitude of reduction to shortages. If such commitments are made, undoubtedly the three states9

would each contribute; because the plan is silent on this, one might assume incorrectly tha t it would only be Nebraska‟s hardship to find the water.

The USFS goes on to say the example offset

- driven acreage retirements provided by Twin Platte NRD likely do not represent the approach NPPD would take. The example uses an array of north/south sections immediately west of GGS so the stream depletion factors (SDF) vary widely (from 15 to 96%) and average 56%. There is no explanation or justification for this. Entities looking either to secure offsets (e.g. Central Platte NRD in their existing water banking program) or secure new supply for river flows (e.g. PRRIP as part of the 50,000

- 70,000 shortage reduction objective) are targeting irrigated land with higher SDFs. Presumably NPPD would use a similar approach, when possible, resulting in less acreage retired from irrigation. Accordingly, economic impacts from irrigated acreage retirements would be reduced proportionately. Finally, some of

the statements about the economic impacts infer that NPPD would acquire the land in fee title, not just the water right for retirement (e.g. the $88,000,000 total cost for land acquisition).

The USFS suggests that the plan has not sufficiently considered all potential, feasib le sources for this amount of water. It was suggested that the Nebraska parties could be taking the approach of “where there is a will there is a way”, similar to how new agricultural, commercial or industrial water users would investigate possible sources to accommodate their needs (e.g. ethanol plants).

Response to Comment 5 : During discussions with EPA on the water resources issue, it was NDEQ‟s understanding that

EPA wanted estimates on the „cost of water.‟ The SIP makes a good faith effort to do es timate such costs. However, a ll throughout the discussion on water, NDEQ clearly points out the moratorium that has been in place on the establishment of new uses of surface and groundwater

in the Twin Platte Natural Resources District. The issue is whet her it is appropriate to cause/contribute to another environmental problem for questionable benefit and high cost in

another.

There is one ethanol plant in the Twin Platte NRD (TPNRD) that pre

- dates the moratorium. Expansion plans for the plant were put on hold due, in part, to the difficulty in obtaining new water. The TPNRD is predominantly agricultural. The example provided regarding SDFs was that, an example to illustrate how not all wells would be considered equal for purposes of meeting offset req uirements. If required to pursue the installation of a water intensive control measure such as dry or wet scrubbing , the actual strategy for NPPD would largely depend upon the willingness of irrigators in the area to sell land and their water rights.

T he NDEQ evaluated NPPDs water needs in terms of what dry and wet scrubbing would require and an industry average. Therefore, the offsets required by NPPD were not presented as a worst case scenario, but rather a „reasonable

- case‟ scenario.

It is critic al to remember that NPPD GGS is located in an area where water is a real environmental issue. It is located in an area designated as over

- appropriated. As demonstrated in the SIP, not all areas of Nebraska have an over

- appropriated designation. NDEQ has an obligation to ensure that its decisions are made carefully so as to not exacerbate the issue.10

Proper management of the water resources in Nebraska is an existing, unique environmental

issue . The Natural Resource Districts (NRDs) are charged with wat er shed management and working with the State Department of Natural Resources to develop the integrated management plans to best respond to the local needs of their district. These 23 NRD s are unique to Nebraska

and have been in existence since 1972. As explained in the proposed SIP, the area where GGS is

located is “over

- appropriated”. In 2004, the Nebraska Legislature e nacted a law that mandated

the State Nebraska D epartment of N atural R esources (NDNR) to make a determination of which river basins, su b

- basins or reaches are considered to be fully

- appr opriated or over

- appropriated.

The decision that a basin was “ fully

- appropriated ” or “ over

- appropriated ” would trigger a

moratorium on new surface water and ground water uses and initiates a process with t he affected

local NRDs to develop an integrated management plan (IMP) to govern the apportionment of water resources in these basins. On September 15, 2004, the Director of NDNR issued an order designating portions of the North Platte NRD, South Platte NRD , Twin Platte NRD, Central

Platte NRD and Tri

- Basin NRD as “ over

- appropriated ”

. The GGS facility is located in the Twin Platte NRD within the area designated as “ over

- appropriated ”

. Most of these areas had already

been determined to be “ fully

- appropriate d ” for surface water under the Nebraska system of prior appropriation of surface water rights and not available for new surface water appropriations. The

2004 law mandated moratoriums on new water uses (surface and groundwater) to remain in

effect unless r emoved as a result of implementation of an approved integrated management plan.

A basin is considered “ fully

- appropriated ” if the current uses of hydrologically connected surface water and groundwater in a basin cause, or will cause in the reasonably for eseeable future, (a) the surface water to be insufficient to sustain over the long term the beneficial purposes for which the existing surface water appropriations were granted, (b) the stream flow to be insufficient to sustain over the long term the benef icial uses from wells constructed in aquifers dependent on recharge from the basin‟s river or stream, or (c) reduction in stream flow sufficient to cause Nebraska to be in noncompliance with an interstate compact or decree, formal state contract, or

state or federal laws. Therefore, in “ fully

- appropriated ” and “ over

- appropriated ” basins, a plan for future water use must be put in place. The statutory definition of an “ over

- appropriated ” basin is very precise and related to conditions at a single point in ti me, July 16, 2004.

Areas that were designated as “ over

- appropriated ” were required to develop a plan to reduce

water use to the 1997 level of use within the next 10 years. In “ over

- appropriated ” areas, the water demand already exceeds the current availabi lity of water and the law requires steps be taken to mitigate the situation.

Therefore, there can be no new uses of water (surface and groundwater) without finding acceptable offsets in the area. T he State and the Local agency responsible for water mana gement

must return the water shed to the appropriate balance, so that the availability of water meets the

future demands for water. This responsibility goes beyond the agreements set forth in the Platte River Recovery Implementation Program. This system of water management is unique in the country and a responsible way to manage resources. To think of it in terms of air quality management, it is analogous to non

- attainment. In a non

- attainment area, before a new refinery or other large source of air pol lution could be built, the source would be required to find offsets for pollution in that area before they would be i ssued a permit to build. Non

- attainment areas do not exist everywhere, nor do they exist in all states.11

Comment 6 : Cost Comparison to Ot her Facilities EPA commented that NDEQ should ensure that GGS is compared to representative sources similar to GGS. EPA believes that the Kansas City Power & Light LaCygne and Westar Jeffrey Energy Center facilities are similar to GGS in that the visibili ty impact before control is similar

and the cost to control is similar.

Response to Comment 6 : Looking at Table 9.2 of the Kansas proposed SIP , NDEQ excerpted the following pre

- control impacts from the KCP&L LaCygne and Westar Jeffrey Energy Center faci lities :

Source CACR UPBU GRSA ROMO HEGL MING WIMO BADL WICA Total

Total Number of days during 2001

- 2003 with visibility impact >0.5 dv

KCP&L
La Cygne

Units 1 &

2 204 249 17 21 278 233 142 46 38 1228

Westar
Energy

– Jeffrey

Units 1 & 2 150 161 27 28 182 158 165 82 55 1008

Accord ing to the Kansas proposed SIP; the lower than presumptive levels agreed to by KCP&L were done so to be consistent with an agreement with the Sierra Club and because of ongoing

ozone issues in the Kansas City metro area. For the Westar Jeffrey Units 1 & 2, KDHE indicates that Westar plans to do this through rebuilding existing scrubbers on each unit.

The predicted impact s from the NPPD & OPPD units on the 7 closest Class I areas were :

Sourc e BADL GRSA HEGL MING ROCO WICA WIMO Total

Total Number of days during 2001

- 2003 with visibility impact >0.5 dv

NPPD GGS

Unit 1 & 2 115 15 45 20 42 108 84 429

OPPD Unit 1 11 0 29 11 2 6 19 78

It is clear that the freque ncy of the impacts from the Nebraska facilities is less than half that of the Kansas facilities. Additionally, the circumstances for both of the Kansas sources are

different than the Nebraska sources. Neither of the Nebraska sources is located in an area with an ongoing ozone issue, nor is there an agreement in place for other purposes to meet certain levels of control. None of the 3 Nebraska units are currently fitted with a scrubber device to be rebuilt. Therefore, the Kansas facilities are not compar able to the Nebraska ones because 1) in the case of KCP&L, costs were being incurred anyway for purposes other than visibility; 2) in the case of Westar, costs of retrofitting and refiguring the source would be very different; 3) the frequency of impacts a re much less for the Nebraska sources ; and 4) Kansas does not apparently have an issue with availability of water in the area where these facilities are located.12

Comment 7 : Visibility Improvement Calculations EPA recommended that NDEQ consider calcula ting visibility improvement at multiple Class I areas. EPA noted that many other states had calculated visibility improvement over multiple

Class I areas.

Response to Comment 7 : See responses to previous comment related to $/ dv

. Nebraska confirmed the methodology used for $/dv was the same as that used by other states. See Table 10.19 of the SIP.

Comment 8 : Endangered Species EPA commented that NDEQ should clarify and bolster its discussion related to endangered species if it intends to utilize the information for the SO 2 BART determination. In its analysis, NDEQ suggested that low water availability could impact species such as piping plover, whooping crane, least tern and pallid sturgeon. In the proposed SIP, the NDEQ mentioned the

Platte River Recovery Implementation Plan (PRRIP) reaching target water flows in the Platte River. EPA asked that NDEQ provide information on what the target flows are for the protection of these species and how increased consumptive water use by GGS would negatively impact meeting those target rates. EPA also noted that if endangered species are looked at, then the positive and negative impacts should be looked at, so such things as reduced mercury

emissions should be looked at.

Response to Comment 8 : Should EPA r equire the use of a water intensive device, a full endangered species evaluation and consultation with the Nebraska Game and Parks as well as the Federal Land Managers would need to occur in order to ascertain the impact to the Platte River as well as on t he water resources

o f the State. Mercury is a known global issue and it is known to transport long distances. Mercury does naturally occur in environment, but is also emitted through the combustion of coal. According to EPA, c urrent estimates are that l ess than half of all mercury deposition within the

U.S. comes from U.S. sources. C oal

- fired electric power plants account for about 50% of total U.S. manmade mercury emissions. While there may be some benefit to endangered species or

habitats in other ar eas, e valuating the impacts of controls in an objective and quantitative manner to endangered species on the Platte River would be extremely difficult to measure and would not be practical.

Comment 9 : Other Non

- Air Impacts EPA commented that the NDEQ d id not fully evaluate the energy and other non environmental impacts fully. EPA thinks it would be helpful to include in the analysis information regarding costs to build additional landfill facilities to handle the increased amounts of waste products and the costs to build additional evaporator systems or disposal ponds.

Response to Comment 9 : The impacts from energy were evaluated in the BART analysis.

The impacts due to whether landfills would need to be permitted and built were dependent upon pendi ng decisions regarding whether the waste products could still be used for beneficial

pur poses and how this type of waste would be categorized. EPA had yet to decide the category13

of waste, which would impact the costs involved in disposal of waste. Regard less, there would be waste disposal costs. The costs involved would only result in an increase in operation and

maintenance costs for the source.

NDEQ did later evaluate DSI and included the costs involved. The life of the current landfill

was expecte d to be greatly shortened due to the amount of sorbent involved to control sulfur. This evaluation was included. Again, to control SO 2 in a non

- water intensive manner resulted in another environmental issue related to waste disposal.

Comment 1 0 : Presu mptive BART for Nebraska City Station (NCS 1) EPA would like to affirm its belief that the NDEQ should consider at least the presumptive SO 2 BART emission rate as appropriate for (NCS 1). EPA continues to assert that due to the unit‟s
size, and based on E PA‟s interpretation of the Regional Haze Rule and Appendix Y to the Regional Haze Rule, that presumptive BART controls should be considered by the NDEQ for this unit and the basis for the determination fully explained.

Response to Comment 1 0 : EPA has not presented any legal evidence to support their argument as to why NCS 1 should be a presumptive unit. The basis for the BART control decision is fully explained in the BART permit decision which is a part of the SIP.

Comment 1 1 : Emissions Inventory

EPA commented that NDEQ should address discrepancies in the SIP so that all data provided in its emission inventory summary are consistent with the data provided in the cited references or the NDEQ should explain any differences between the resource and the ND EQ‟s Regional Haze

SIP.

The discrepancies are noted below:

Comment 11 a.

Response to 1 1 a : NDEQ agrees that the way the ammonia information was presented was not clear. The

information related to ammonia emissions was taken from a different r esource than the Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005). There is still uncertainty with regard to ammonia emission inventory development.14

CENRAP commissioned a study by Sonoma Technology, Inc specifically for ammonia emiss ion inventory development in the CENRAP state and tribal areas. It was a part of Appendix 8.3 of the proposed SIP ( Research and Development of Ammonia Emission Inventories for the Central States Regional Air Planning Association; Final Report; STI

- 902501

- 2241

- FR; October 30, 2003) . This report focuses on making enhancements to traditional ammonia emission inventory methodologies that were appropriate for the CENRAP area. Since this report looked more comprehensively at the ammonia inventory, and reported emissions overall that were higher for the state, that report was the basis for the ammonia values found in the proposed SIP , to be

conservative

.

To make the information regarding NH3 more clear, NDEQ has created a new table detailing the

ammonia invent ory and has removed reference to ammonia from Table 8.1. The discussion regarding biogenic emissions and the contents of the Table 8.2 (now Table 8.3) remains unchanged.

Summary of changes made to the tables below: NH 3 Column Removed from Table 8.1. New Table 8.2 created. Subsequent tables in Section 8 were renumbered.

Table 8.1 2002 Nebraska Emissions Summary, by Pollutant and Source Category Source Category VOC NO

x SO 2 PM 10 PM 2.5 Tons per Year

Point 1 7,274 58,619 73,487 13,105 4,638

Area 2 66,76 9 15,023 7,748 447,703 83,852

On

- Road 3 43,113 61,850 1,822 1,277 930

Non

- Road 4 24,882 119,568 11,011 7,491 6,785

Fires 5
(Ag & Prescribed) 3,204 679 268 5,057 3,956

Nebraska Total 145,242 255,739 94,336 474,633 100,161

1 Point Source Information taken from Table 2c Summary of Point Source Emissions by State and Pollutant Pechan, Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005)

2 Area Source Information taken from Table 2b Summary of Area Source Emissions by State and Pollutant Pechan, Refinement of CENRAP’s 2002 Emission s Inventories (August 31, 2005)

3 On Road Information taken from Table 2e Summary of On Road Source Emissions by State and Pollutant Pechan, Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005)

4 Non Road Information taken from Table 2d Summ ary of Non Road Source Emissions by State and Pollutant Pechan, Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005)

5 Fire information taken from Table 2

- 1 and Table 2

- 2 of Research and Development of Planned Burning and

Emission Inventorie s for the Central States Regional Air Planning Association (July 2004)15

Table 8.2 2002 Nebraska Ammonia (NH 3 ) Emissions Summary, by Source Category 6

Source Category NH 3 Tons per Year

Livestock 96,983 Fertilizer Application 64,443 Biogenics (Soil) 7,829

Point 800

On

- Roa d 1,521

Non

- Road 320

Miscellaneous 7,912

Nebraska Total 179,808

Comment 1 1 b. EPA believes the date for footnotes 2

– 6 for Table 8.1 is incorrect. The date in the proposed SIP is August 31, 2005; EPA believes the appropriate document date is April 28,

2005.

Response to Comment 1 1 b:

The date and reference is correct. The document to which EPA is referring to is the Consolidation of Emissions Inventories Report which was also prepared by E.H. Pechan &

Associates for CENRAP. The Cons olidation of Emissions Inventories Report (April 28, 2005) was refined on August 31, 2005, with the Refinement of CENRAP’s 2002 Emissions Inventories. This document was contained in Appendix 8.3 of the proposed SIP.

1 1 c. EPA believes the VOC area source emissions noted in Table 8.1 are 3,197 tons per year less

than what was referenced in the SIP.

Response to Comment 1 1 c: Except as previously noted for ammonia (NH 3 ), as can be seen from the Table 2b taken from the Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005) , the VOC emissions match those in the NDEQ proposed SIP. NDEQ also would like to note the typo in the EPA comments regarding the PM10 emissions.

6 Ammonia information taken from Table B

- 1 Appendix B of Research and Development of Ammonia Emission Inventories for the Central States Regional Air Planning Association (October 2003)16

Comment 1 1 d. EPA was unable to verify the nu mbers for the “on

- road” emissions in Table 8.1.

Response to Comment 1 1 d: Except as previously noted for ammonia (NH 3 ), as can be seen from the Table 2e taken from the Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005) , the on

- road emiss ions match those in the NDEQ proposed SIP.17

Comment 11 e. EPA was unable to verify the numbers for the “nonroad” emissions in Table 8.1.

Response to Comment 1 1 e: Except as previously noted for ammonia (NH 3 ), as can be seen from the T able 2d taken from the Refinement of CENRAP’s 2002 Emissions Inventories (August 31, 2005) , the non

- road emissions match those in the NDEQ proposed SIP.

Comment 1 1 f. EPA noted that NDEQ should revise the SIP‟s Table 8.3 titled “2018 Nebraska Projected Emissions Summary, by Pollutant and Source Category (modeled)” and Table 8.4 “2018 Percent Changes in Nebraska Emissions 2002 to 2018, By Pollutant and Source Category”

to assure that the lack of SO 2 control on NPPD and OPPD are properly accounted for. The United States Forest Service (USFS) also noted that the CENRAP Technical Document had presumed a certain level of SO 2 reductions to be achieved through BART by 2018 (29%). The USFS believed that Chapter 8 should be revise d to reflect the projected 2018 levels of SO 2 with

no EGU BART controls.

Response to Comment 1 1 f : NDEQ had included a discussion of the discrepancies between the predicted 2018 emissions and those to be achieved through the proposed SIP. To be clearer, NDEQ included tables showing18

what the EGU emissions have been for the last 10 years and what they are assumed to be in 2018 as a result of all the measures discussed in the proposed SIP.

Actual SO 2 Emissions from EGUs (Tons per Year)

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Gerald

Gentleman

Station 31,297 32,152 31,089 32,035 28,171 31,135 28,815 31,362 31,931 29,741

Whelan Energy

Center 2,008 2,007 2,152 2,352 2,563 2,330 2,207 2,229 2,001 2,301

Lon D Wright

Power Plant 1,088 978 1,017 1,183 1,332 1,401 1,708 1,958 1,250 1,206

Nebraska City

Station 16,205 12,820 15,052 15,593 17,550 14,994 14,173 17,498 19,074 14,296

North Omaha

Station 11,799 11,509 11,730 16,125 16,705 14,315 14,749 15,012 13,159 10,515

Pl atte 2,436 2,250 2,194 2,158 2,476 2,637 2,641 3,086 2,679 2,365

Sheldon 5,410 5,624 4,478 4,768 4,878 4,403 4,627 4,552 5,395 3,758

Total 70,243 67,340 67,712 74,214 73,675 7 1,215 68,920 75,697 75,489 64,182

Comment 1 2 : Adequacy of the Long Term Strategy The National Parks Conservation Association (NPCA) out of Knoxville, TN and Plains Justice (PJ) out of Billi ngs, MT submitted a joint comment letter regarding the adequacy of the BART determinations and the Long Term Strategy in the proposed SIP. NPCA and PJ believe that NDEQ did not meet its responsibility for establishing a long term strategy to help achieve reasonable progress goals in Class I areas in other states. The United States Forest Service ( US FS) also submitted comments stating similar concerns. The commenters note that i n developing the Long

- Term strategy, the State must consider all anthropogenic sources of visibility impairment and evaluate different emission reduction strategies beyond those prescribed by the BART provisions. At a minimum, the state must consider the following

elements: Emission reductions due to ongoing air pollution control p rograms, including

measures to address reasonably attributable visibility impairment;
Measures to mitigate the impacts of construction activities;
Emissions limitations and schedules for compliance to achieve the reasonable progress goal;

Source retirem ent and replacement schedules;
Smoke management techniques for agriculture and forestry management purposes including plans as currently exist within the State for these purposes;19 Enforceability of emission limitation s and control measures; and

The ant icipated net effect on visibility due to projected changes in point, area, and mobile emissions over the period addressed by the long

- term strategy. Their concern is that during their review of Nebraska‟s proposed BART emission limits and controls, they b elieve that the state has not required emissions controls and limits that reflect

BART for the state‟s BART

- eligible sources. They are also concerned that the state has not required any source emission reductions or source retirements other than its propos ed BART requirements to meet reasonable progress requirements in its Long

- Term Strategy. They are concerned that the lack of reductions may impact the ability of nearby states to meet their Class I visibility goals.

Response to Comment 1 2 : Each of the a bove elements were included and documented in the subsections of Section 11.3 of

the SIP

.

Comment 1 3 : Available Technologies or Upgrades were not Evaluated

The FLMs and NPCA commented that control options were not evaluated. In the instance of

SO 2 , dry sorbent injection (DSI) was not evaluated for either facility. DSI does not require water, and can provide 50

- 80% emission reductions depending on the configuration of the facility and the system.

In addition, NDEQ‟s BART determinations did not consider upgrades to the existing PM control equipment at NCS (electrostatic precipitator (ESP)) or GGS (fabric filters). Each of these technologies could likely improve performance with upgrades, and this option should be evaluated as part of the BART determinati ons.

Response to Comment 1 3 : NDEQ did not evaluate upgrades for PM control because the attribution associated with PM

from the sources was insignificant

. NDEQ continues to believe that the current level of control is sufficient for purposes of visibility protection.

NDEQ agrees that DSI should have been evaluated for GGS due to the potential for its impacts

to the South Dakota Class I areas

. NDEQ requested a BART analysis from NPPD and NDEQ

conducted a subsequent evaluation of DSI, which has been inclu ded in Section 10.6.4 of the SIP.

Comment 1 4 : Overemphasis of Incremental Costs The NCPA commented that NDEQ overemphasized incremental costs when determining cost

effectiveness. Cost effectiveness is the economic criterion used to determine whether a gi ven control option has a dv erse economic impacts compared to controls at similar facilities. Cost, estimated using the total annual cost method, is measured in terms of annualized control costs, and cost effectiveness is measured in annual dollars per ton o f pollutant removed. Two cost metrics can be considered: (1) total cost effectiveness and (2) incremental cost effectiveness. Total cost effectiveness, the metric most commonly used, is calculated by dividing annualized cost by the reduction in emissions. Incremental cost effectiveness compares the costs and emission performance with those of the next most stringent option. Incremental cost effectiveness should not be used to eliminate a top control option as BART if the total cost20

effectiveness is accepta ble. As described in the NSR Manual, “undue focus on incremental cost effectiveness can give an impression that the cost of a control alternative is unreasonably high, when, in fact, the total cost effectiveness, in terms of dollars per total ton removed, is well within the normal range of acceptable...costs.” In this case, NDEQ highlights the incremental cost many times as a primary means of comparing one control technology to another. For instance, the incremental costs of adding SCR in addition to OFA/LNB is considered in all of the BART

determinations. They believe t he significant emphasis on incremental costs versus total costs for the technology is inappropriate. Incremental costs should be a secondary, not primary,

consideration.

Response to Comment 1 4 : In the final preamble to the regional haze rules, EPA speaks to the use of incremental costs as a

decision

- making tool: “We have finalized this section of the guidelines with some changes to how it was proposed. States have flexibility in how they calcul ate costs. We believe that the Control Cost Manual provides a good reference tool for cost calculations, but if there are elements or sources that are not addressed by the Control Cost Manual or there are additional cost methods that could be used,

we beli eve that these could serve as useful supplemental information.

In addition, the guidelines continue to include both average and incremental costs. We continue to believe that both average and incremental costs provide information useful for making contro l determinations. However, we believe that these techniques should not be misused. For example, a source may be faced with a choice between two available control devices, control A and control B, where control B achieves slightly greater emission reduction s. The average cost (total annual cost/total annual emission reductions) for each may be deemed to be reasonable. However, the incremental cost (total annual cost A

– B/total annual emission reductions A

– B) of the additional

emission reductions to be achieve d by control B may be very great. In such an instance, it may be inappropriate to choose control B, based on its high incremental costs, even though its average cost may be considered reasonable.

Finally, it is important to note that, while BART determin ations are focused at individual sources, it is likely that in response to SIP requirements, States will be making BART determinations for many units in a subject source category all at the same time. In doing so, States are likely to

compare costs across each source category as well as looking at costs for individual units in order to respond to SIP requirements in an efficient manner (from the State‟s perspective).”

NDEQ used bot h average and incremental costs consistent with the methods described above. NDEQ did incorrectly use the term “incremental” in some places when average cost effectiveness was actually being evaluated. That was corrected in the SIP.

Comme nt 15 : Cost per Ton Metric is Down

- played The NCPA is concerned about how NDEQ determined cost effectiveness. Cost per ton of pollutant removed is a longstanding metric used to evaluate the cost

- effectiveness of control technologies; in the regional haze context, cost per deciview can also be used to inform cost

effectiveness evaluations, as a supplement to the cost per ton calculation. In this case, even without consideration of inflated cost estimates or discounted control efficiencies the cost per ton, both total and incremental, of all evaluated

– and rejected

– technologies is well within the range of cost

- effectiveness of other BART determinations

. Much higher measures of cost

-21

effectiveness than those rejected by the state have been used in both BART analyses and rule

making instances, over $10,000/ton in some instances. NDEQ itself notes that $2,500

– 2,700/ton is “reasonable”; all of the total costs are at or below this level.

Response to Comment 15 : Cost per ton of pollutant removed is the metric used in the Prevention of Significant Deterioration Program when making a decision on the Best Available Control Technology for new sources. This program is designed to improve visibility. The decision is for the control technology on existing sources. In the Regional Haze Rules, and as a result of American Corn Growers vs. EPA, visibility i mprovement must be considered when making such decisions. In the final rules, EPA provided for $/dv as a metric States could use to evaluate cost effectiveness. The $/dv metric couples the visibility improvement to the investment, just as the $/ton remov ed does in the PSD program. NDEQ evaluated cost effectiveness as one of the metrics in the overall analysis. As discussed in previous comments, the State has discretion as to the weight to give each metric. NDEQ evaluated the $/dv metric consistent wit h the evaluation conducted by

other States.

Comment 16 : SCR Costs are Overestimated

The FLMs commented that t he cost estimates are missing significant amounts of information that is necessary for the public or other agencies to be able to thoroughly revie w and comment on them. For instance, unsubstantiated vendor quotes underlie a large portion of the cost estimates. Nonetheless, it is clear that some of the relied on costs are overestimated. The capital costs for a retrofit of SCR at GGS Units 1 and 2, as reported on a $/ kw basis, are significantly higher than those found by several industry studies of SCR installations. Those reports found a range of installed costs between $83

– 300/kw , the highest of which were highly complex retrofits with

severe space constraints.

Response to Comment 16 : Costs to retrofit an existing facility will vary widely from site to site depending upon the individual circumstances. The cost information provided by NPPD and OPPD was determined to

be reasonable. In the case of N PPD there are severe space constraints on

- site which would require unique retrofits causing an escalation in costs . According to a 2007 analysis conducted for LADCO, actual retrofits for SO 2 and NO

x controls were costing more than the estimates provided b y EPA and other regulators. Actual FGD costs were about $200/ kw higher and SCR costs were $25

- $45/ kw higher.

The primary reason for not requiring SCR for control was due to the incremental effectiveness.

The primary reason s for not requiring SO 2 con trol for OPPD was the lack of significant visibility improvement as well as the cost effectiveness . The primary reason s for not requiring SO 2 control

for NPPD was due to other non

- air quality impacts and the resulting effect on the environment as well as t he cost effectiveness

.

Comment 1 7 : CALPUFF versus CAMx The USFS commented that in Section 10.2, Nebraska described the assistance received from EPA Region 7 with regard to modeling. The USFS justified how one may use CAMx modeling22

to inform visibility decision making in light of the framework provided by Appendix Y (Regional Haze Rules) and Appendix W (Guideline on Air Quality Models).

Response to Comment 17 : The US EPA speaks to the issue of using CALPUFF versus a regional model such as CAMx in

the f inal regional haze rule:

“Theoretically, the CALPUFF chemistry simulations, in total, may lead to model predictions that are generally overestimated at distances downwind of 200 km. Again, States can make judgments concerning the conservativeness or over estimation, if any, of the results. The use of other models and techniques to estimate if a source causes or contributes to visibility impairment may be considered by the State, and the BART guidelines preserve a State‟s ability to use other

models. Regi onal scale photochemical grid models may have merit, but such models have been designed to assess cumulative impacts, not impacts from individual sources. Such models are very resource intensive and time consuming relative to CALPUFF, but States may consid er their use for SIP development in the future as they are adapted and demonstrated to be appropriate for single source applications. However, to date, regional models have not been evaluated for single source applications. Their use may be more appropriat e in the cumulative modeling options

discussed above.”

It was for the above reasons that NDEQ chose to use CALPUFF as a tool for decision

- making

purposes.

Comment 18 : Emissions Impact Potential for NPPD on Nearby Class I Areas The USFS provided informati on regarding the potential for emissions from NPPD GGS to impact Class I areas in adjacent states, particularly in South Dakota. The USFS believes that NPPD GGS plays a central role in haze formation at Badlands National Park and Wind Cave

National Park f

or both nitrate and sulfates. The USFS provided CALPUFF and CAMx modeling results showing that NPPD GGS impacts for 2002 were greater than 0.5 dv on 15% of the days and 23% of the days, respectively.

Response to Comment 1 8 : NDEQ addressed the potential for sulfates and nitrates from Nebraska sources to contribute to Class I area visibility in Section 11.2 of the proposed SIP. NDEQ believes that nitrates are a greater contributor than sulfates from Nebraska, and that the reductions in visibility due to N Ox

control will benefit the South Dakota Class I areas.

Comment 19 : Linkage Between PSD and Visibility Days The USFS requested that NDEQ recognize the link between the Prevention of Significant Deterioration Program and the need to protect visibility

. Th e NPS and FWS also requested a discussion about how the visibility improvement goals under the regional haze rule are incorporated in Nebraska‟s Prevention of Significant Deterioration program.

Response to Comment 19 : NDEQ addressed the linkage between the PSD (NSR) program and the need to protect visibility in Section 11.3.2 of the proposed SIP.23

Comment 2 0 : Smoke Management Plans (SMPs) The USFS requested that Nebraska not include a smoke management plan as an appendix to the Regional Haze SIP because in the event that the SMP is modified, a SIP revision may be

necessary.

Response to Comment 2 0 : NDEQ addressed the issue of smoke management under Section 11.3.4 of the proposed SIP.

Comment 2 1 : Reasonable Further Progress

The National Park Service and Fish and Wildlife Service provided comments regarding their concerns that they do not believe Nebraska met the requirement to address enforceable limitations, compliance schedules, and other measures necessary to achieve reasonable progress goals establis hed by States with Class I areas. They point to information in the proposed SIP which shows that point source SO 2 emissions account for 78% of total SO 2 emissions in Nebraska‟s 2002 inventory of which , electric generating units (EGU) account for 92% of po int

source SO 2 emissions. Section 8.3.1.3 indicates that the 2018 inventory assumes significant

reductions in SO 2 from electric generating units based on assumptions of the Integrated Planning Model. NDEQ does not document any actual SO 2 controls. They infer that no reductions in SO 2 emissions from point sources are expected and that, based on Tables 8.1 and 8.3, SO 2 emissions from Nebraska in 2018 are underestimated by 21,218 tons, or 25% in the CENRAP and WRAP 2018 modeling. They request that Nebraska require SO 2 controls consistent with emission assumptions.

Response to Comment 21 : NDEQ recognized up front in the discussion on the emissions inventory in Section 8 of the proposed SIP that there was a discrepancy between what was modeled for 2018 and wh at the proposed SIP would require. To make it clearer, additional discussion has been added to Section

8.

Comment 22 : Emissions Inventory for EGUs The NPS and FWS requested that NDEQ include a description of the emissions for the BART eligible units. A ppendix 10.1 indicates that Gerald Gentleman Units 1 and 2 combined have potential SO 2 emissions of 79,200 tons/year and Nebraska City Unit 1 has potential SO 2 emissions of 45,696 tons/year. They asked that NDEQ confirm and provide the actual annual

SO 2 emissions from the 2002 CENRAP inventory for these three units, similar to the nitrogen oxide (NO

x ) information in Table 8.5.

Response to Comment 2 2 : The proposed SIP directs the reader where to find a complete description of all BART eligible

units. The complete actual inventories for all EGUs in the state (coal and natural gas fired) are included in Section 8 for the last 10 years. A projection for 2018 was included with an explanation.

Comment 2 3 : Five Factor Analysis The NPS and FWS requested that ND EQ provide in Chapter 10, a summary of the five factor analyses for Gerald Gentleman and for Nebraska City. They suggested BART analyses be24

summarized in the SIP Narrative and reference the appropriate appendices for further

information. Step 1: Identify the available retrofit technologies for SO 2 and NO

x . For SO 2 this should include lime spray dryer and dry sorbent injection as control options with lower water use requirements than wet flue gas desulfurization. For NO

x this should include

selective non

- catalytic reduction (SNCR) technology in addition to selective catalytic reduction (SCR). Step 2: Eliminate technically infeasible options. Step 3: Evaluate effectiveness of control options. Step 4: Evaluate impacts and document results. Step 5: Sele ct Best Available Retrofit Control

Response to Comment 2 3 : Brief s ummaries are included as requested. Dry Sorbent injection was added. Dry and wet scrubbing were already evaluated, as well as SNCR and SCR. Full summaries are included in the Appendices for Section 10.

Comment 2 4 : Controls for Nebraska City The NPS and FWS believe that presumptive controls should be required at Nebraska City Station. They believe that the information EPA Region 7 provided to Nebraska in a letter dated January 23, 2009, required that the total plant capacity (BART plus non

- BART units) be used to determine if an Electric Generating Unit (EGU) is greater than 750 MW and that any units in existence at the time of the BART determination are to be included in the total plant capacity.

They note a typo in the text in Section 10.5 incorrectly referring to Unit 2 as BART eligible. The NPS and FWS asked for the MW capacity of Units 1 and 2. They believe it is unacceptable for Nebraska to provide the legal requirements for pre sumptive controls rather than discussing the BART analysis and visibility impacts from Unit 1.

The Federal Land Management agencies believe that SO 2 control on Unit 1 is cost effective and reasonable. They are concerned that NDEQ dismissed control due to high $/ dv improvement for

one Class I area. They, like others, believe that it is appropriate to consider both the degree of visibility improvement in a given Class I area as well as the cumulative effects of improving visibility across all of the Cla ss I areas affected. They argue that i f emissions from Nebraska City Station are reduced, the benefits will be spread well beyond only the most impacted Class I area, and this must be accounted for.

The NPS and FWS recommended that OPPD obtain curren t cost estimates for all alternatives rather than simply scaling 2003 information to the present. Current vendor cost estimates may be quite different and the errors of scaling could be large. In an effort to make OPPD‟s results

for all control alternati ves comparable to the universe of other companies‟ BART

d eterminations, cost calculations based on use of the most recent OAQPS Control Cost Manual should be performed. They believe the $/ kw are too high.

The FLMs suggest that OPPD consider upgrades/impr oved operation as a BART alternative for

PM

.25

The NPS and FWS express concerns that in OPPD‟s BART Analysis document, OPPD argues

that certain visibility improvements are “well below the minimum perceptible dv change”. The

FLMs believe it is incorrect to dismiss a control strategy on the basis that the resulting improvement is not perceptible or significant.

Response to Comment 2 4 : See responses to comments 2, 10 and 13

. Also see the Response to the OPPD BART Permit comments in Appendix 10.8.

Comment 2 5 : Controls for Gerald Gentleman The FLMs do not agree with the BART determination of no SO 2 controls for Gerald Gentleman. Was dry sorbent injection considered? If not, why not? Nebraska provides an elaborate justification that limited water availabili ty prohibits the application of wet flue gas desulfurization (FGD) at Gerald Gentleman without discussing the viable alternatives that are being used in western states. The economic factors influencing the economy of Nebraska are much greater than the pos sible retirement of irrigated acreage to obtain water rights for the power plant.

The NPS and FWS provided substantial comment on the costs of controls provided by NPPD. Their main concerns were with the methodology utilized and their belief that the re trofit would not involve severe space constraints

. In total, they believe the costs are overestimated.

The FLMs expressed concern that NDEQ did not take into account the potential improvements to visibility in the other Class I areas where GGS is also c ausing or contributing to visibility impairment. They argue that if emission s from the BART source are reduced, the benefits will be spread well beyond only the most impacted Class I area, and this must be accounted for. While NDEQ presented data describin g improvements to visibility at Badlands NP that would result from the various control scenarios it investigated, the FLMs would like an explanation of how NDEQ incorporated this information on impacts upon all Class I areas into its BART decision.

The NP S and FWS expressed concern over the analysis of SCR. They believe that NDEQ

should evaluate the cost

- effectiveness of SCR in combination with combustion controls rather than evaluating the addition of SCR to LNB/OFA as an incremental cost. The FLMs prov ide data to support their position that NDEQ should determine SCR with LNB/OFA BART for NPPD GGS. They believe the cost information provided by NPPD overstates the costs involved for installation of an SCR system. They argue that the LNB/OFA burners curr ently on one of the

GGS units were not in existence at the time the BART Guidelines were finalized and therefore cannot be separated from the LNB/OFA+SCR system evaluation. Likewise, with SO 2 control, the FLMs present many of the same concerns over the cos ts. They believe the $/ kw are too high.

The FLMs also urge that NDEQ require emission limits significantly lower than the presumptive

levels for both NO

x and SO 2

.

Response to Comment 2 5 : See the responses to comments 2, 5, 6, 13 and 16

. Also see the Response to the NPPD BART Permit comments and Final Fact Sheet found in Appendix 10.8.26

Comment 2 6 : Baseline, Current, and Natural Visibility Conditions The FLMs requested a summary of baseline conditions at key Class I areas (e.g. Badlands,

Hercules Glad e) impacted by Nebraska emissions to establish the relative contributions of pollutant species, seasonal trends in pollutant contributions, and priority for emissions controls. Because the Class I areas are geographically distant, the priority for emissio ns controls may differ among the Class I areas.

Response to Comment 26 : Nebraska has no Class I Federal areas within its borders. Therefore, Nebraska does not have an obligation to include this information in its SIP.

Comment 27 : Monitoring Strategy

The FLM noted that measurements at IMPROVE sites and from special studies are discussed but no results are presented.

Response to Comment 2 7 : Nebraska has no Class I Federal areas within its borders. Therefore, Nebraska does not have an obligation to inclu de this information in its SIP. While results were not presented, discussion

was included as to how the information was used by CENRAP

.

Comment 28 : Emissions Inventory

T he FLMs asked for additional discussion on ammonia (NH 3 ) emissions in Nebraska in 20 02.

The FLMs disagree with ignoring NH 3 as a contributing pollutant, even if it is not a criteria pollutant. They also asked for a discussion of the change in NH 3 in 2018 in Table 8.3 and Section

8.3.1.5.

The FLMs asked for additional information on th e 2018 projections to provide better explanation of the source categories contributing to point source emissions of SO 2 and NO

x . This information was not presented in either Appendix 8.2 (SMOKE reports in Microsoft Access) or Appendix 9.1 (ENVIRON technic al report). This information is critical to supporting an adequate reasonable progress analysis.

Response to Comment 28 : See response to comment 11.

Comment 29 : BART The FLMs asked that NDEQ include the CENRAP BART Modeling Protocol in the Appendices

a s it has been referenced in the BART Modeling Protocol for Gerald Gentleman and Nebraska City.

Response to Comment 29 : The CENRAP BART modeling protocol is a refer ence. It has been added as an Appendix 9.2

.

Comment 30 : Reasonable Progress/Long Term S trategy
The FLMs stated that Table 11.1 reports the net improvement in Light Extinction at neighboring Class I areas based on source apportionment modeling and what appear to be incorrect27

assumptions for SO 2 emissions in Nebraska. The FLMs conclude that i f t he emissions assumptions are invalid

, Nebraska‟s d emonstration of reasonable progress is also invalid.

The FLMs noted that in Section 11.2: Colorado mentions in its regional haze SIP consultation

with Nebraska on the BART determination for Gerald Ge ntleman due to the plant‟s impact to Rocky Mountain National Park , but Nebraska does not include Colorado in its summary.

The NPS and FWS note that in South Dakota‟s SIP, a 36% reduction in Nebraska SO 2 emissions

were used in setting reasonable progress goals for Badlands and Wind Cave National Parks. They calculated this to be 23,623 tons lower than what a no EGU SO 2 controls in Nebraska SIP would garnish

.

The NPS and FWS requested that Nebraska re

- evaluate what reductions are necessary to support

t he reasonable progress goals of neighboring states. The regional haze rule requires that the State include in its long term strategy all measures needed to achieve its apportionment of emission reductions and to identify all anthropogenic sources of visi bility impairment considered in developing the long term strategy. They are concerned about Nebraska demonstrating that its emissions sources are being controlled and that reasonable progress is being met in reducing anthropogenic emissions.

Response to Comment 3 0 : See response to previous comments 12, 18, 21 and 22

. The FLMs are correct that Colorado did provide comments on the GGS BART permit as well as the proposed SIP. Section 11.2 has been revised accordingly.

Commen t 31 : Water Demands on Nebra ska The Twin Platte Natural Resources District (TPNRD) provided comments regarding the impact

SO 2 controls may have on TPNRD. The TPNRD agree d with the May 11, 2011 Fact Sheet (BART & PSD Analysis For the NPPD GGS) prepared by the Nebraska Departme nt of

E nvironmental Quality (N DEQ), which states that there is a significant non

- air quality environmental impact for NPPD regarding water use, if either Wet or Dry Flue Gas Desulfurization (FGD) control technology is required.

The TPNRD stated that the Platte R iver Basin in western Nebraska has been designated by the Nebraska Depa rtment of Natural Resources (N DNR) as Over Appropriated, as required by Nebraska law enacted in 2004. The designation that the Platte River Basin is Over Appropriated required the NE D e partment of N atural R esources (NDNR) and the TPNRD to jointly develop an Integrated Management Plan (IMP). The IMP provides that there are no new depletions to ground water or surface water, that the Platte River must be returned to 1997 flows within the

f irst ten years following approval of the IMP which occurred in 2008, and the Platte River Basin in western Nebraska ultimately must be returned to Fully Appropriated. To accomplish the requirements of the IMP, since 2004, there can be no new depletions of water within the TPNRD, and the TPNRD must provide offset water to the Platte River in the amount of 7,700

acre

- feet within the first ten years and a yet undetermined amount of offset water to the Platte River to reach Fully Appropriated.28

They concluded that f

inding offset water in an area that is Over Appropriated is very difficult and very expensive, as described in the May 11, 2010 NE DEQ Fact Sheet. If NPPD were to have to find water for either Wet or Dry FGD, they would be competing with the TPNRD an d

the other Natural Resources Districts within the Platte River Basin.

Response to Comment 31 : NDEQ appreciates the feedback from the Twin Platte NRD and agrees with the conclusions.