~~ NORTH DAKOTA

~J DEPARTMENT a! HEALTH

March 11, 2005

Mr. John Graves

Environmental Manager

Minnkota Power Cooperative

1822 Mill Road

P.O. Box 13200

Grand Forks, NO 58208-3200

ENVIRONMENTAL HEALTH SECTION

1200 Missouri Avenue, Bismarck, NO 58504·5264

P.O. Box 5520, Bismarck, NO 58506·5520

701.328.5200 (fax)

www.ndhealth.gov

Re: PSO Applicability Determination

M.R. Young Station

Unit 1 Turbine Upgrade

Dear Mr. Graves:

We have reviewed your letters of August 9, 2004 and March 7, 2005

regarding the proposed upgrade to the Unit 1 turbine at the Milton

R. Young Station near Center, North Dakota. Your proposed changes

appear to be very similar to those proposed by the Detroit Edison

Company at the Monroe Power Plant in 2000 (i.e., Dense Pack

Project). The Detroit Edison project was reviewed by U.S.

Environmental Protection Agency (EPA) and a determination was

provided on May 23, 2000. The EPA determined that the dense pack

project at the Monroe Power Plant was not routine maintenance and

repair. The EPA also outlined the steps that were necessary in

order to prove that the dense pack project was not a major

modification under the Prevention of Significant Deterioration

(PSD) Program. In summary. Detroit Edison was required to prepare

calculations that show the modification would not have a

significant increase in emissions and was required to track annual

emissions from the facility.

Based on the Detroit Edison interpretation, the Department believes

your turbine upgrade at Unit 1 does not qualify as routine

maintenance or repair. Therefore. it is incumbent upon Minnkota

Power Cooperative to demonstrate that the proposed changes are not

a major modification under PSD.

You have proposed testing of the turbine and generator set to

determine maximum short-term input and output conditions before and

after the change. These tests are acceptable to prove that a

modification has not taken place under the New Source Performance

Standards. However. these types of tests do not address annual

Environmental Health

section Chiefs Office

701.328.5150

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701.328.5188

Municipal

Facilities

701.328.521'

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Waste

Management

701.328.5166

Water

Quality

701.328.5210
Mr. Graves 2 March 11, 2005

operation of the facility. The Department is concerned that the

proposed changes could allow Minnkota Power to operate the unit at

a higher level of utilization after the proposed changes are made.

Therefore, there is a potential to increase emissions on an annual

basis.

Minnkota must follow the procedures outlined in the North Dakota

Air Pollution Controls to demonstrate that a major modification

will not occur. The rules (commonly known as the WEPCO rule - NDAC

§33-l5-l5-01.l. a (4)) require Minnkota to compute baseline actual

emissions (or other parameter such as heat input) and project the

future actual emissions from the modified unit for a two year

period after the physical change, or another two year period that

is more representative of normal operations.

In addition, Minnkota must maintain and submit to the Department on

an annual basis for a period of ten years from the date the unit

resumed regular operations information demonstrating that the

renovation did not result in a significant emissions increase.

This period of time may be reduced by the Department to a period of

not less than five years if Minnkota can provide adequate

demonstration that the changes have not resulted in a significant

increase of emissions.

The calculation of the baseline emission rates (or other parameter)

and the projected future emissions must be submitted to the

Department. The method of calculating the baseline and the

monitoring methods to track emissions should also be included.

If you have any questions regarding this issue, please feel free to

contact Tom Bachman of my staff at 701.328.5188.

Respectfully,

/I

.:~

Terry L. O'Clair, P.E.

Director

Division of Air Quality

TLO/TB:csc

xc: Lyle Witham, Assistant Attorney General

Kathleen Paser, EPA - Region VIII

Dave Glatt, EHS
To be inserted in email when I get it back!

August 23, 2004

Discussion of MimtkotalMilton R. Young turbine upgrade project

In regard to facsimile sent to Kathleen Paser by Tom Bachman: An August 9, 2004, letter

from John T. Graves, Envrionmental Manager ofMinnkota Power Cooperative to Teny O'Clair,

Air Program Director, North Dakota Department of Health.

Minnkota is considering retrofitting the main stearn turbine at the Milton R. Young

Station. This rotrofit is a turbine upgrade, the goal of which is to increase the electrical output of

Unit I, by increasing the efficiency ofthe High PressurelIntennediate Pressure (HPIIP) turbine.

Based on the information provided in August 9, 2004 letter, and determinations made by

both EPA Region 8 and North Dakota with regard to other turbine upgrade projects in North

Dakota1

, this modification to the plant should not be considered routine maintenance, repair, and

replacement.

Since Minnkota maintains that there will be no design change ofthe heat input to the

boiler and no significant emission increases, then the project would not be subject to PSD

pennitting requirements by this virtue. However, as North Dakota required with Basin Electric's

Leland Olds' turbine upgrade, the emissions should be tracked as required by the WEPCO rules.

IOttertail Power's Coyote Station, April 2001. Great River Energy's Coal Creek Station,

October 1998. Basin Electric Power Cooperative's Leland Olds Station, April 2003.
Ul)/&'.J/V'I.I..I. .•"

NORTH DAKOTA DEPARTMENT OF HEALTH

Environmental Health Section

Locatlon:

1200 Missouri Avenue

Bismarck, NO 58504·5264

Fax':

701-321>-5200

Maili"g Addr"ss:

P.O. Box 5520

Bismarck, NO 58506-5520

Fax #:_~03)all.. - &ob)

Phone:, _

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Phone: (701) 328-5188

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MinnkotaPower

Mpcj COOPERATIVE, INC.

\822 Mil Raad • P.O. 80x 13200' Gnnd forts. NO 5020.&-3200 • Phllll8 (701) 795~OOO

August 9, 2004

:

Mr. TeTTY O'Clair

Division of Air Quality

North Dakota Department of Health

P.O. Box 5520

Bismarck. ND 58506-5520

..'.

Subject: PSD Applicability Determination

Milton R. Young Station, Unit 1

.Turbine Upgrade

.Dear Mr. O'Clair:

•,

Your Touchstone EneriY· Parmer ".

-

Minnkota Is considering the retrofitting the main steam turbine at Milton R. Young

Station, Un~ 1. This retrofit is similar to turbine upgrades that have taken place at other

power plants in the nation. In North Dakota, turbine upgrades were accomplished at

Coal Creek Station near Underwood, North Dakota. (The turbine retrofit Minnkota is

considering is not mechanically jdentical to the Advanced Design Steam Path upgrade

accomplished at Coal Creek Station, but rather similar in that they both increase the

t"rbine cycle efficiency.) The project is currently scheduled to be in~iated in October

2004 with a request for bids, and be completed in the year 2006.

. The goal of the project is to increase the electrical output of Unit 1, by increasing the

efficiency of the High p'ressurellnterrnediate Pressure (HPIIP) turbine. The project

would :n..·c~vG. rep!~dng ~!I cl t.'le HP/:P C',1iiica;" internals. So~e of the mair. rtems t';c;~

would be replaced include the HPIIP rotor with associated buckets, the HP/IP

diaphragms. and the inner cylinder shell. Items not currently being considered for

replacement include the HPIIP outer cylinder, the associated outer cylinder equipment,

the control valves, and the #1 & #2 bearings. General Electric refers to this retrofit as a

"Dense Pack". Other vendors have different names for this type of turbine retrofrt.

The North Dakota Air Pollution Control RegUlations, Section 33-15-1 &-01, defines a

"Major Modification" as •... any physical change in, or change in the method of

operation of a major stationary source that would result in a significant net emissions

increase of any air contaminant subject to regulation under North Dakota Century Code

chapter 23-25." (Emphasis added.) The regulations also indicate that "A physical

change or change in the method of operation does not include: (a) Routine
maintenance, repair, and replacement..:. Section 33-15-15-01 of the Reguiations

indicates that any major stationary source undergoing a major modification is subject to

regulation under Section 33-15-15-01, commonly referred to as the Prevention of

Significant Deterioration, PSD, regGlation.

This turbine retrofit wjll be designed specifically so as not to impact the operation or

capacities of the boiler. The below described approach illustrates how this can be

accomplished.

The drawing below illustrates the Milton R. Young Unit 1 energy cycle. The bolle, cycle

converts heat input in the fonn of fuiilto heat output in the fonn of steam. The turbine

cycle accepts this heat inpu1 in the fonn of steam and converts it into heat output in the

fonn of electrical energy. '. ..

____ J _ , ,

: Losses :

l----t-----~

_____L , ,

l Losses :

./ :_~ l

:--B~;I:;;C~~j~-1

: Heat Input : ,

.: Btu/Hr ,-:'~-+I

: (Fuel) :

,---------------~

Boiler

Cycle

I

Turbine Cycle ! f-~ Heat Input L

BtulHr T'" , : '-----_.------ --.--

Turbine

Cycle --_.~._------

: Electrical :

f---_: Output i ~--- - ---- ----'

, If the turbine cycle heat input remains unchanged, the boiler cycle heat ou1put will

remain unchanged. Correspondingly, the boiler cycle heat input will also remain

unchanged. This is the basis for the assertion that the turbine retrofit will not impact the

operation of the boiler. To maintain the current turbine cycle heat input, Minnkota will

require that the retrofit be specifically designed such that the heat input to the turbine

cycle after the retrofit will be the same (within the limils of the manufactures design

margins) as before the retrofit. The currenl heal input 10 the Unil1 turbine cycle will be

determined by tests utilizing indUStry recognized test codes and procedures such as the

ASME (American Society of Mechanical Engineers) Perfonnance Tesl Code 6. The

successful retrofit supplier will be contractually bound to perfonn the appropriate tesling

as part of their scope of work. The tests normally would be conducted at the following

operating conditions, as a minimum:
1. The first test condition would utilize the steam cycle configuration typically used

to determine the maximum eiectrical output as defined by the Uniform Rating of

Generating Equipment (URGE) test.

2. The second test condition/steam cycle configuration would be at "Valves Wide

Open", all feedwater heaters in service, at design throttle pressure.

As illustrated previously, the modifications to the turbine will not impact the heat input to

the bolier. Therefore, this retrofit will not result in any increases in hourly emissions of

any air contaminate. Both unlis at Milton R. Young Station are "base load" units; they

do not respond to hourly changes in load, but are operated at the maximum generation

levels possible based upon boiler operating conditions (coal quality, ash fouling, boiler

water and steam purity, etc). As this turbine retrofit project will not impact the hours of

operation or the levels of operation of the Unit 1 bolier, annual emissions will not be

impacted by this project (Annual eITlissions may increase or decrease in future years.

This may occur due to changes in c6al qualliy, changes in boiler outage rates, changes

in the accuracy oflhe CEMS, etc.) .'. __

Putting aside any consideration of this project being excluded from the definition of a

"Major Modification" by the "routine maintenance. repair, and replacement" exclusion,

Minnkota has determined that this project will not be a "major modification" because

," .there will be no significant net emissions increase. Therefore, this project will not be

subject to regulation under Section 33-15-15-01, Minnkota requests your concurrence

in this determination.

Should you have any questions concerning the above, please contact me at 701-795-

4221.

John T. Graves, P.E.

Environmental Manager

C: Luther Kvemen

David Sogard

Tom Anseth

Stu Libby

Kevin Thomas

Reger Gazur