# ~ NORTH DAKOTA**~** DEPARTMENT 

### of HEALTH

September 16

, 2015

Mr. Carl Daly (8P-AR)

Director

, Air Programs

U.S. EPA

, Region 8

1595 Wynkoop Street

Denver

, CO 80202-1129 ENVIRONMEN T AL HEALTH SEC TI O N

Gold Seal Center

, 9 1 8 E. D ivi de A ve

. Bismarck

, ND 5850 1 -19 4 7

701

. 328.5200 ( fa x)

www

. ndhea lt h

. g ov

Re : S0 2 Designation Recommendations

Dear Mr. Daly:

On March 2

, 2015

, the U.S. District Court for the Northern District of California entered a

Consent Decree between the EPA

, Sierra Club and Natural Resources Defense Council that

requires the EPA to complete designations for the 2010 I-hour S0 2 NAAQS. This i s to be

accomplished in three rounds with the first round completed b y Jul y 2

, 2016. EPA has

established a deadline of September 18

, 2015 b y which states ma y submit updated

recommendations and supporting information for this first round of designation s

. Attached to

thi s letter is a letter from Governor Dalr y mple with North Dakota ' s updated designation

recommendations. In addition

, attached are dispersion modeling anal y ses for the Coyote Station

, Leland Olds Station/Coal Creek Station (combined anal y si s ) and T ioga Gas Plant as well as

other supporting information for those recommendations.

In a conversation with E PA Region 8

, EPA agreed to allow the Department further time to

re v ie w the modeling anal y ses and provide an y supplemental findings following that revie w

. The

Department will suppl y E PA any supplemental information based on our review of those

anal y ses b y December 1

, 2015

.

If y ou or y our staff has any questions regarding thi s submittal

, please contact Tom Bachman of

m y staff at ( 701) 328-5188

.

# C)d

Terr y L. O'Clair

, P .E.

Director

Di v ision of A ir Qualit y

TLO / TB:saj

E nc:

Environme n tal Health

Section Chiefs Office

701

. 328

. 5150 D ivision of

Air Q u a l i t y

701.328.5188 Division of

Municipal Facilities

701

. 328

. 5211

Printed on recycled paper

. Division of

Waste Management

701

. 328

. 5166 Division of

Water Quality

701

. 328

. 5210

# - State of 

# North Dakota

O ffice o f th e G ove rn or



## Jack Dalrymple

Gov e rnor

Ms. Gina McCarthy

c/o Mr. Shaun McGrath

U

. S. EPA, Region 8

1595 Wynkoop Street

Denver, CO 80202-1129 September 16, 2015

Re: Updated Sulfur Dioxide Designations Recommendation

Dear Administrator McCarthy:

On June 22, 2010, the United States Environmental Protection Agency (EPA)

published its Final Rule regarding the Primary National Ambient Air Quality Standards

(NAAQS) for sulfur dioxide (S02). See 75 F.R. 35520. On May 25, 2011, the State of

North Dakota submitted its recommendation (with supporting data) that the entire state

be designated as attainment for the new one-hour S02 NAAQS. This recommendation

was based on the results of monitoring data from an extensive monitoring network

located across the state.

On March 2, 2015, the U.S. District Court for the Northern District of California

entered a Consent Decree that requires EPA to make further designations for the onehour S02 NAAQS. No later than July 2, 2016, the EPA must designate two groups of

areas: 1) areas that have newly monitored violations of the new one-hour NAAQS; and

2) areas that contain any stationary source that emitted more than 16,000 tons of S02 in

2012 or emitted more than 2,600 tons of S0 2 and had an annual average emission rate of

at least 0.45 lb / 10 6 BTU of S0 2 in 2012. The State of North Dakota has four plants that

fit into the 2016 groups specified in the Consent Decree. These include the Lelands Olds

Station, the Coal Creek Station, the Coyote Station and the Tioga Gas Plant.

Based on the data collected by the Department of Health and information

provided by the owners of the above listed facilities, it is recommended that the area

around the Leland Olds Station, the Coal Creek Station and the Coyote Station be

designated "attainment" for the 2010 one-hour S0 2 NAAQS (see attachments).

The Tioga Gas Plant has recently undergone an expansion to enable the facility to

process sweet gas and reduce flaring incidents. Because of the characteristics of the gas

processed, the plant experienced periodic upsets and malfunctions. These upsets resulted

in elevated concentrations of sulfur dioxide. An enforcement action was taken and several

600 E Bou l evard Ave. • B i s m a r ck, ND 58505-0001 • P h one: 701.328.2200 • Fax : 701.328

. 2205 • www.governor. n d.govMs. Gina McCarthy

September 16, 2015

Page 2

operational changes have been implemented at the plant. The Department of Health believes

the issues that resulted in elevated concentrations in the immediate area of the plant have been

rectified. Although the latest ambient data indicate the plant is complying with the NAAQS, it is

recommended the immediate area around the Tioga Gas Plant be designated as "unclassifiable"

while the Department of Health continues to gather additional data to demonstrate the plant is

in compliance. In earl y 2018, after more data has been collected, a recommendation for

reclassification will be submitted based on the monitoring data from 2015-2017 and other

available information. Attached to this letter are ambient monitoring data and other supporting

information for this recommendation.

The Department of Health has not full y reviewed the modeling data that is submitted

with this recommendation. However, as agreed in a telephone conversation with staff at EPA

Region 8, the data will be reviewed by the Department of Health and an y supplemental

information submitted b y December 1, 2015.

If y ou have an y questions, please contact the Division of Air Quality at the Department

of Health at (701)328

- 5188.

C: Terry Dwelle, State Health Officer Sincerel y

,

Jack Dalrymple

Governor

Dave Glatt, Environmental Health Section Chief

Terry O'Clair, Division of Air Quality Director

E nc.

37:68:56

# ..

Tioga Gas Plant

The Tioga 

### Gas Plant was constructed in 1954 in Williams County North Dakota near the town of

Tioga to process gas generated by the first oil wells drilled in North Dakota. The plant, which

has had many owners, is currently owned and operated by Hess Corp (Hess Tioga Gas Plant,

LLC)

. The plant was originally designed to process 100

- 120 million standard cubic feet per

day (MMSCF) of sour gas (3

. 5 - 4% H2S). In 1967, a 105 long ton per day (LTD) sulfur

recovery unit (SRU) was added to the plant which was replaced in 1991witha220 LTD SRU.

Since 1987, the Department has required Hess to operate two ambient air quality monitoring

sites near the plant. One site is approximately 0

. 75 miles northeast of the plant and the other is

approximately 0

. 5 miles southeast of the plant. The data from these sites has not been certified

by either the Department or Hess as being accurate

. In addition, the quality assurance

procedures did not strictly adhere to 40 CFR 58 requirements

.

In 2008, development of the Bakken shale formation accelerated, primarily for oil. However,

there is a significant amount of gas produced with the oil from the Bakken. This gas is primarily

sweet gas(< 0.0004% H2S). The Tioga 

### Gas Plant began processing the Bakken gas which

helped reduce flaring in the field and offset the decline in gas production from older non-Bakken

wells with sour gas

. Because the Tioga plant was designed to handle sour gas, the plant

experience numerous operational problems as it switched over from sour gas processing to a

sour/sweet 

### mix including the Bakken gas

. Starting in 2012, these operational problems lead to

plant upsets where Hess had to "learn" how to operate the plant with the sour/sweet gas mix

.

These upset resulted in equipment malfunctions, periodic flaring and reduced gas production.

During several of the upsets, elevated levels of S02 above of the 1-hour S02 design value were

recorded at the southeast monitor (no elevated levels have been monitored at the site northeast of

the plant). Initially, Hess believed that the problems would be readily solved; however, due the

characteristics of the Bakken gas, consistent operations with the sweet/sour gas mixture proved

to be more difficult than expected

.

On February 13, 2013 the Department issued Hess a Notice of Violation for these elevated S02

levels. In December of 2013, a Consent Agreement was signed by the Department and Hess

(attached)

. This Consent Agreement required Hess to complete facility upgrades to improve the

SRU operations and, most importantly, other upgrades that improved the reliability of the plant

to minimize upsets that were occurring too frequently

. Since these upgrades were installed and

fine tuned in July 2014, plant operations have stabilized and become consistent. Only one hour

of monitored S02 concentrations has exceeded the 75 ppb design value in last year (see attached

data)

. This occurred on February 25, 2015 and was attributed to an abnormal startup of the plant.

As shown on the attached graph, the S02 emissions from the plant have been decreasing since

2005

.

### Attached is a dispersion modeling analysis prepared for Hess by Bison Engineering that uses

current emissions rates (starting with September 2014) and three years of meteorological data

.

The results indicate the plant will comply with the NAAQS (maximum design concentration of

50 ppb or 131 μg/m 3 )

. 

### Although the Department has not reviewed the modeling in depth, it will

do so and provide any updates or additional information by December 1

, 2015

.

The Department believes the incidences of elevated S0 2 concentrations at the plant have been

resolved

. Both the frequency and duration of plant upsets have been substantially reduced

.

Normal operations of the plant over many years have shown compliance with the ambient

standards and actual emissions are decreasing

. Because of the high 99th percentile values of

the daily maximum I-hour concentration in 2013 and 2014 ( 264 ppb and 180 ppb respectively)

and the averaging of three years of monitoring data for determining compliance with the onehour S02 NAAQS

, the 2015 and 2016 design values will likely be elevated

. The Department

proposes that the area be classified as " unclassifiable " until monitoring data are available for

2017

. At that time

, the Department will propose a reclassification (attainment or non-attainment)

based on the design value for that year and other pertinent information

.

### \



## Leland Olds Station

Coal Creek Station

Combined Analysis

The Leland Olds Station is a lignite/subbituminous coal-fired steam electric generating plant

located in southeast Mercer County approximately four miles southeast of Stanton, North

Dakota

. The plant consists of two units with a nameplate capacity of 222 MW e and 44 7 MW e

.

Sulfur dioxide emissions are controlled by two new wet scrubbers. The Unit 2 scrubber was

placed into service in October 2012 and the Unit 1 scrubber in June 2013

. The plant has a BART

S02 limit of 0.15 lb/10 6 

### Btu (effectively 393 lb/hr and 770 lb/hr for Units land 2 respectively) or

95% reduction which was effective in the Leland Olds Title V Permit to Operate on January 1,

2014

. The units vent emissions through separate flues in a common stack that is 600 feet high

.

The plant is operated by Basin Electric Power Coop

.

The Coal Creek Station is a lignite-fired steam electric generating plant located approximately

six miles southwest of Underwood

, ND in McLean County

. The plant consists of two units each

with nameplate rating of 605 MWe

. Sulfur dioxide emissions are controlled by a wet scrubber

on each unit. Each unit vents through a separate stack that is approximately 683 feet high

. The

plant is operated by Great River Energy.

Attached is dispersion modeling analysis report prepared for Basin Electric and Great River

Energy by AECOM Environmental. The analysis was conducted using the AERMOD modeling

system, version 15181

. Emissions data for the Leland Olds Station used the BART allowable

emission rate for the 2012-2014 period

. 2012

- 2014 S02 CEM data was used for the Coal Creek

Station

. The report includes the results from two separate dispersion modeling analyses

. The

first analysis utilized the EPA regulatory default options. The results indicate a maximum

predicted design concentration of 163

. 8 μg/m 3

. 

### The second analysis utilized the AERMET

ADJ_ U* and the AERMOD LOWWIND3 options

. The results of that analysis indicate a

maximum design concentration of 117

. 2 μg/m 3

. 

### The Department has not reviewed the analyses

.

The Department will review the analyses and submit any additional or updated information by

December 1

, 2015

.

Based on the results of the attached dispersion modeling analyses, it recommended that the area

around the Leland Olds Station and Coal Creek Station be designated "attainment ".

## Coyote Station

The Coyote Station is a lignite-fired steam electric generating unit located approximately 3 miles

southwest of the City of Beulah in Mercer County

. The plant consists of a single unit and has a

nameplate rating 450 MWe

. Sulfur dioxide emissions are controlled by a spray dryer/baghouse

system and emissions vent from a stack that is 498 feet tall

. The plant is operated by Otter Tail

Power Co

.

Attached is dispersion modeling analysis report prepared for Otter Tail by AECOM

Environment. The analysis was conducted using the AERMOD modeling system, version

15181

, and continuous emissions monitor data for 2012-2014

. The report includes results for

two different methods of conducting the analysis

. The first method uses the EPA regulatory

defaults for all options

. The results of this analysis predict a maximum design concentration of

115

. 9 μg/m 3

. 

### The second analysis utilized the AERMET ADJ

_ U* and the AERMOD

LOWWIND3 options. The results of the second analysis are similar to the results of the

regulatory default analysis with a design concentration of 106

. 1 μg/m 3

. 

### Because of the short

time available to make an updated classification recommendation, the Department has not

reviewed the analyses

. The Department will review the analyses and submit any additional or

updated information by December 1

, 2015

.

There are five sulfur dioxide ambient air quality monitoring sites located within approximately

20 kilometers of the Coyote Station

. The attached monitoring results from these sites for 2012-

2014 indicate design values for 1-hour S0 2 concentrations well below the NAAQS

. The

maximum design value of any of these monitors is 47 ppb or 63% of the NAAQS in 2012

. However

, data for 2013 and 2014 show declining concentrations with a maximum design value

in 2014 of34 ppb or 45% of the NAAQS

.

Based on the results of Otter Tail's dispersion modeling analyses for the Coyote Station and the

nearby ambient monitoring data

, it is recommended that the area around the station be designated

" attainment " for the 1-hour S02 NAAQS

.AmbientMonitoringData1-Hr.502VicinityofCoyoteStationYEARBeulahDGC12DGC14DGC16DGC17Annual3-yr.Avg.Annual3-yr.Avg.Annual3-yr.Avg.Annual3-yr.Avg.Annual3-yr.Avg.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.99thpctl.(ppb)(ppb)(ppb) (ppb)(ppb)(ppb)(ppb) (ppb)(ppb)(ppb)2006262826393620074037363038200831322931262929334339200926323835273023272836201052364638543644323736201123343138323838353132201228343738273858474136201318231728222722391930201423233329262521341926>graphicArea:MercerCounty,NDlutant:5021r:2014:eptionalEvents:Included(ifany)863247860958870046870039870236394330253323362333602636521365193656775445654MonitorValuesReport01.07None3805700046024Highway200NotinaCityMercerND0801.15None00.94None01.11NoneO0.87None380570102Oge#12380570118Oge#141380570123Oge#161380570124Oge#17NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08jetailedinformationaboutthisreport,includingcolumndescriptions,athttp://www.epa.gov/airquality/airdata/ad_about_reports.html#monatareportsareproducedfromadirectqueryoftheAQSDataMart.ThedatarepresentthebestandmostrecentinformationavailabletoEPAfromstateagencies.However,maybeabsentduetoincompletereporting,andsomevaluesmaychangeduetoqualityassuranceactivities.TheAQSdatabaseisupdateddailybystate,local,andIorganizationswhoownandsubmitthedata.Pleasecontacttheappropriateairqualitymonitoringagencytoreportanydataproblems.>://www.epa.gov/airquality/airdata/ad_contacts.html>:lersarecautionednottorankordergeographicareasbasedonAirDatareports.Airpollutionlevelsmeasuredataparticularmonitoringsitearenotnecessarilyrepresentativeeairqualityforanentirecountyorurbanarea.reportisbasedonmonitor-levelsummarystatistics.Airqualitystandardsforsomepollutants(PM2.5andPb)allowforcombiningdatafrommultiplemonitorsintoasite-level11arystatisticthatcanbecomparedtothestandard.Inthosecases,thesite-levelstatisticsmaydifferfromthemonitor-levelstatisticsuponwhichthisreportisbased.Paqe1of1Source:U.S.EPAAirData<http://www.epa.gov/airdata>Generated:September2,2015>graphicArea:MercerCounty,NDlutant:5021r:2013:eptionalEvents:Included(ifany)8664298702218675268647336483282619233222183653173654223625223621119271434473MonitorValuesReport00.56None3805700046024Highway200NotinaCityMercerND0800.83None00.83NoneO0.79NoneO0.42None380570102Oge#12380570118Dgc#141380570123Oge#161380570124Oge#17NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08:letailedinformationaboutthisreport.includingcolumndescriptions,athttp://www.epa.gov/airquality/airdata/ad_about_reports.html#monatareportsareproducedfromadirectqueryoftheAQSDataMart.ThedatarepresentthebestandmostrecentinformationavailabletoEPAfromstateagencies.However,maybeabsentduetoincompletereporting,andsomevaluesmaychangeduetoqualityassuranceactivities.TheAQSdatabaseisupdateddailybystate,local,andIorganizationswhoownandsubmitthedata.Pleasecontacttheappropriateairqualitymonitoringagencytoreportanydataproblems.i://www.epa.gov/airquality/airdata/ad_contacts.html>:lersarecautionednottorankordergeographicareasbasedonAirDatareports.Airpollutionlevelsmeasuredataparticularmonitoringsitearenotnecessarilyrepresentativeeairqualityforanentirecountyorurbanarea.reportisbasedonmonitor-levelsummarystatistics.Airqualitystandardsforsomepollutants(PM2.5andPb)allowforcombiningdatafrommultiplemonitorsintoasite-level11arystatisticthatcanbecomparedtothestandard.Inthosecases,thesite-levelstatisticsmaydifferfromthemonitor-levelstatisticsuponwhichthisreportisbased.Paqe1of1Source:U.S.EPAAirData<http://www.epa.gov/airdata>Generated:September2,2015>graphicArea:MercerCounty,NDlutant:5021r:2012:eptionalEvents:Included(ifany)8279628690438729398737728710723542356761283477373639273661058366104136419576911MonitorValuesReport0None00.92None00.67NoneO1.27NoneO1.24None13805700046024Highway200NotinaCityMercerND08380570102Oge#12380570118Oge#14380570123Oge#161380570124Oge#17NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08NotinacityMercerND08..,fotailedinformationaboutthisreport,includingcolumndescriptions,athttp://www.epa.gov/airquality/airdata/ad_about_reports.html#monatareportsareproducedfromadirectqueryoftheAQSDataMart.ThedatarepresentthebestandmostrecentinformationavailabletoEPAfromstateagencies.However,evaluesmaybeabsentduetoincompletereporting,andsomevaluesmaychangeduetoqualityassuranceactivities.TheAQSdatabaseisupdateddailybystate,local,andIorganizationswhoownandsubmitthedata.Pleasecontacttheappropriateairqualitymonitoringagencytoreportanydataproblems.i://www.epa.gov/airquality/airdata/ad_contacts.html>::lersarecautionednottorankordergeographicareasbasedonAirDatareports.Airpollutionlevelsmeasuredataparticularmonitoringsitearenotnecessarilyrepresentativeeairqualityforanentirecountyorurbanarea.reportisbasedonmonitor-levelsummarystatistics.Airqualitystandardsforsomepollutants(PM2.5andPb)allowforcombiningdatafrommultiplemonitorsintoasite-level11arystatisticthatcanbecomparedtothestandard.Inthosecases,thesite-levelstatisticsmaydifferfromthemonitor-levelstatisticsuponwhichthisreportisbased.Paqe1of1Source:U.S.EPAAirData<http://www.epa.gov/airdata>Generated:September2,2015