### December 19, 2012

MEMORANDUM

From: William H. Maxwell

EPA/SPPD/ESG (D243-01)

To: Docket Number EPA-HQ-OAR-2009-0234

Subject: Meeting with Utility Ai r Regulatory Group (UARG)

Attendees :

Lee Zeugin, Hunton & Williams

Bill Wehrum, Hunton & Williams

Mike Geers, Duke Energy

Michael Rossler, EEI

Sarah Markham, Southern Company

Ralph Roberson, RMB Consulting

Peter Tsirigotis, EPA

Nick Hutson, EPA

Robert Wayland, EPA (by phone)

Ravi Srivastava, EPA (by phone)

William Maxwell, EPA (by phone)

Discussion :

A general discussion was held regarding clarifyi ng questions from Utility Air Regulatory Group on the

proposed Mercury and Air Toxics St andards (MATS) reconsideration issues. The attached documents

were discussed.

### MATS Startup and Shutdown

EPA Meeting

December 19, 2012

Key Messages

 Startup does not simply end when either steam or electricity is produ ced. Startup involves

the “setting in operation” of the boiler and its associated air pollution control systems, which

does not necessarily occur with the first appearance of steam or electricity.

 Emissions during startup and shutdown can be highly variable and sufficient data does not

exist to establish separate emission standards during these periods. Wo rk practice standards

during startup and shut down are appropriate.

 Emissions variability during st artup generally occu rs until the emission control devices can

be fully engaged or operating. These are the ex act emissions that EPA states “it do[es] not

have sufficient data...on which to set emissions standards.”

 Southern Company suggests that EPA revise th e startup definition to include the complete

“setting in operation” of the boiler and its associated emission control systems and to

recognize that various control systems must be phased in according to their unique time,

temperature, and/or pressure requirements. This could be accomplished through a unit by

unit work practice plan that is developed and submitted to the Title V permitting authority.

Background

The proposed definition of startup does not ac count for the actual period of startup for

which the work practice standards are needed. St artup does not simply end when either steam or

electricity is produced. Neither does mercury cont rol immediately then reach peak performance.

Startup involves the “setting in operation” of the boile r and its associated air pollution control

systems, which does not necessari ly occur with the first appear ance of steam or electricity.

Defining startup as Southern Company suggests a bove would ensure that all pollution control

equipment is started in a safe and environmentally efficient manner.

The figures below show two actual startups from Southern Company coal-fired power

plants. The figures labeled (a) illustrate the star t and duration of various activities that take place

during startup including:

 

### Supplemental fuel fire

 

### Steam usage

 

### Coal fire

 

### Precipitator energized 1

 

### Unit online ( i.e. , selling electricity to the grid)

 Scrubber in service 2

 

### SCR inlet opening 3

 

### Ammonia flow for the SCR

 

### 25 percent load

The figures labeled (b) below illustrate mercury emissions during startup.

1 Electrostatic Precipitators (ESPs) may be only partia lly energized during initial startup and appropriate ESP

operation is unit specific.

2 Scrubbers may be in service, but not functioning properly at the beginning of startup. Scrubber operation is unit

specific. Scrubbers may be under required bypass for blackstart situations.

3 The end of the SCR inlet opening bar denotes that the SCR is completely open and ready for ammonia injection

once the appropriate temperature is reached.

### Figure 1(a). Startup Events of a 900 MW Supercritical Unit on April 16, 2011

Figure 1(b). Mercury Emissions During 900 MW Supercritical Unit Startup on April 16, 2011 End of

Startup as

Defined by

EPA in final

rule (steam

use )

End of Startup

as Defined by

EPA in

proposed

reconsideration

(electricity

generation)

### Figure 2(a). Startup Events of a 900 MW Supercritical Unit on May 5, 2011

Figure 2(b). Mercury Emissions for 900 MW Supercritical Unit Startup on May 5, 2011 End of Startup

as Defined by

EPA in

proposed

reconsideration

(electricity

generation)

End of

Startup as

Defined by

EPA in final

rule (steam

use )

# SUPER

- CRITICAL SYSTEM START

- UP

STEP 1 :

C. Cvetic

12/1 7 /2012

# SUPER

- CRITICAL SYSTEM START

- UP

STEP 2 :

C. Cvetic

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- CRITICAL SYSTEM START

- UP

STEP 3 :

C. Cvetic

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STEP 4 :

C. Cvetic

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# SUPER

- CRITICAL SYSTEM START

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STEP 5 :

C. Cvetic

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# SUPER

- CRITICAL SYSTEM START

- UP

STEP 6 :

C. Cvetic

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# SUPER

- CRITICAL SYSTEM START

- UP

STEP 7 :

C. Cvetic

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# SUPER

- CRITICAL SYSTEM START

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STEP 8 :

C. Cvetic

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STEP 9 :

C. Cvetic

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# SUPER

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STEP 10 :

C. Cvetic

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# SUPER

- CRITICAL SYSTEM START

- UP

STEP 11 :

C. Cvetic

12/1 7 /2012WHZ_01_AEP_1-5101-10.dgn 10/27/2011 11:22:46 AM