# COST ANALYSIS OF MERCURY MONITORING TECHNIQUES

TASK 1: COST OF MERCURY MEASUREMENT TECHNIQUES

DRAFT REPORT, Revision 1

3 NOVEMBER 2003
Infrastructure, buildings, environment, communicationsCost Analysis of Mercury Monitoring Techniques

Task 1: Cost of Mercury Monitoring Techniques

Draft Report, Revision 1 Brent Hall Project Manager

Carl Singer Project Engineer

Michiel Doorn Project Engineer Prepared for: U.S. Environmental Protection Agency
Clean Air Markets Division

Prepared by: ARCADIS G&M, Inc. 4915 Prospectus Drive
Suite F
Durham
North Carolina 27713
Tel 919 544 4535
Fax 919 544 5690

Our Ref.: RN096402.0001

Date: 3 November 2003

This document is intended only for the use of the individual or entity for which it was prepared and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. Any dissemination, distribution, or copying of this document is strictly prohibited.i Table of Contents

List of Tables iii
List of Acronyms iv

1. Introduction 1

1.1 Scope 1

1.2 Clear Skies Act 2

1.2.1 Common Provisions 3

1.2.2 Mercury Emissions Reductions 4

1.2.3 Performance Standards for New Sources 4

1.3 General Assumptions 4

2. Ontario Hydro (OH) Analysis 7

2.1 Background 7

2.1.1 Scope and Applicability 7

2.1.2 Technique 7

2.1.3 Accuracy and Precision 8

2.2 Assumptions 8

2.3 Capital Costs 8

2.4 Annual Costs 9

2.4.1 Labor Costs 9

2.4.2 Subcontract and Other Direct Costs (ODC) 9

2.4.3 Annualized Capital Costs 10

2.4.4 Total Annualized Cost 10

2.5 Uncertainties 10

3. Carbon Trap Analysis 12

3.1 Background 12

3.1.1 Preliminary Methods 12

3.1.2 Scope and Applicability 14

3.1.3 Technique 14

3.1.4 Accuracy and Precision 16

3.2 General Assumptions 17

3.3 Capital Costs 18

3.4 Annual Costs 19ii Table of Contents

3.4.1 Labor Costs 19

3.4.2 Subcontract and ODC 20

3.4.3 Annualized Capital costs 20

3.4.4 Total Annualized Costs 20

3.5 Uncertainties 21

4. CEMS Analysis 23

4.1 Background 23

4.1.1 Scope and Applicability 24

4.1.2 Technique 30

4.1.3 Accuracy and Precision 30

4.2 General Assumptions 32

4.3 Capital Costs 33

4.4 Annual Costs 35

4.4.1 Annual Labor Costs 35

4.4.2 Subcontract and ODC 36

4.4.3 Annualized Capital Costs 36

4.4.4 Total Annualized Costs 36

4.5 Uncertainties 37

5. Fuel Analysis 38

5.1 Background and Methods 38

5.1.1 Scope and Applicability 38

5.1.2 Accuracy and Precision 39

5.2 Assumptions 40

5.3 Annual Costs 41

5.3.1 Labor Costs 41

5.3.2 Subcontract and ODC 42

5.3.3 Total Annualized Costs 42

5.4 Uncertainties 43

6. Discussion and Summary 44

6.1 Comparison Carl: please update this section with revised costs. 44

6.2 Barriers to Cost Analysis 45iii Table of Contents

6.3 Suggestions for Improvements and Additional Research 46

List of Tables

Table 1-1. Projected Emis sions Reductions und er Clear Skies Act (EPA, 2002i.) 3
Table 3-1. Draft MQO for Sorbent Total Mercury by internal Frontier Geosciences Method 13
Table 3.2: Assumed Carbon Trap Analytical Summary 18
Table 4-1. Overview of Mercury CEMs that are (expected to be) Commercially Available in the United States 25
Table 4-2. Operation & Maintenance 28
Table 4-3. CEMS Capital Cost (March 2003) 33

Table 5-1. ASTM D-3684-01 Bias 39
Table 6-1. Summary of Mercury Annual Analysis Costs 44iv Table of Contents

List of Acronyms

ADAES ADA Environmental Solutions

ASTM American Society for Testing and Materials

AWMA Air and Waste Management Association

BACT Best Available Control Technology

BART Best Available Retrofit Technology

CAA Clean Air Act

CEM Continuous Emission Monitor

CEMS Continuous Emission Monitoring System

CRM Certified Reference Material

CVAAS Cold Vapor Atomic Absorption Spectroscopy

CVAFS Cold Vapor Atomic Fluorescence Spectroscopy

DOE Department of Energy

EPA United States Environmental Protection Agency

EPRI Electric Power Research Institute

ETV Environmental Test Verification

ICR Information Collection Request

IGCC Integrated Gasification Combined Cycle

LAER Lowest Achievable Emission Rate

MESA Mercury Speciation Adsorptionv Table of Contents

MQO Method Quality Objectives

NAAQS National Ambient Air Quality Standards

NIST National Institute of Standards & Technology

NSPS New Source Performance Standard

NSR New Source Review

OAQPS Office of Air Quality Planning and Standards

ODC Other Direct Costs

OH Ontario Hydro

PM Particulate Matter

QA Quality Assurance

QSEM Quick Silver Emissions Monitor

RATA Relative Accuracy Test Audit

RDF Refuse Derived Fuel

RSD Relative Standard Deviation

SIP State Implementation Plan

SOP Standard Operating Procedures

TSCA Toxic Substances Control Act

WRAP Western Regional Air Partnership1 Task 1: Cost of Mercury Measurement Techniques

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1. Introduction

1.1 Scope

Anthropogenic mercury emissions are consider ed a potential serious health hazard. As

a by-product of combustion processes, mercur y emitted to the air can be transformed into the highly toxic methyl-mercury form by means of a natural process in the atmosphere. The Mercury Study and the Utility Hazardous Air Pollutant Reports 1 to congress have identified coal-fired power plan ts as the largest anthropogenic source of mercury emissions. In December 2000, the United States Envi ronmental Protection Agency (EPA) made the determination to regulate mercury emissions from coal-fired power plants under section 112 of the Clea n Air Act (CAA) Amendments of 1990. EPA is required to promulgate mercury emissions standard s to electricity generating utility boilers by December 2004, to be im plemented by December 2007. According to the explicit language of the Clean Air Act, these standards must reflect the utilization of “Maximum Achievable Control Technology” (MACT) for mercury.

As a possible alternative the Bush Admi nistration proposed legislation in 2002 under
the Clear Skies Initiative to establish a fl exible, market-based program to reduce and cap emissions of sulfur dioxide, nitrogen oxides, and mercury from coal-fired power plants and other electric power generators. Su ch a program is already in place for sulfur dioxide and nitrogen oxides under th e Acid Rain Program and the NO X State Implementation Plan (SIP) Call.

As part of a mercury control or cap and trade program, EPA will need to implement monitoring requirements that ar e cost-effective, technically viable, contain sufficient quality assurance (QA), and are based on technologies and equipment that are compliance-capable. Mercury emission redu ctions under CAA-MACT or under Clear Skies may have different monitoring requirements.

EPA has conducted several studies to describe and compare various mercury monitoring technologies, as well as a cost-e ffectiveness study based on preliminary

1 U.S. EPA, 1998. Study of Hazardous Air Po llutant Emissions from Electric Utility Steam Generating Units – Final Report to Congress. U. S. EPA, Office of Air Quality Planning and Standards Research Triangle Park, NC 27711. February 1998. EPA-453/R-98-004a2 Task 1: Cost of Mercury Measurement Techniques

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information. 2 This report is a continuation of this previous study and provides a detailed cost analysis of four mercury-monitoring technologies applicable at coal-fired power plants. The technologies are fuel anal ysis, the American Society for Testing and Materials (ASTM) Ontario Hy dro (OH) method, iodated carbon traps, as well as

continuous emissions monitoring systems (CEMS).

1.2 Clear Skies Act

The Clear Skies Act would amend Title IV of the CAA to establis h new cap-and-trade programs requiring reductions of SO 2 , NO X , and mercury emissions from electric generating facilities and amends Title I of th e CAA to provide an alternative regulatory classification for units subject to the cap-and-trade programs. The market-based approach should allow for the implementation of multi-pollutant control systems. Also, the ability to carry over unused allowances is believed to create incentives for early reductions, delivering environmental and huma n health benefits sooner, in exchange for a longer compliance window for source s. Ultimately, the cap ensures that the emission reduction goals are met and ma intained. The EPA projects emission
reductions for SO 2 , NO X , and mercury of 73, 67, a nd 69 percent respectively, compared to 2000 emissions. Table 1-1 incl udes projected emissions reductions. The Act does not require reductions in CO 2 emissions, although there is a provision to
maintain CO 2 monitoring and reporting requirements that currently exist under the
CAA.

As revised by the Clear Skies Act, Title IV of the CAA has five Parts. Part A contains provisions common to the control of all thre e pollutants. Part B contains provisions specifically for sulfur dioxide emission reductions. Part C contains provisions specifically for nitrogen oxides emissi on reductions. Part D contains provisions specifically for mercury emission reductions. Part E contains performance standards for affected units and provisions for re search, environmental monitoring, and
assessment. Part E of the Clear Skies Act includes substantial changes in the New

2 Cadmus Group, 2003. Mercury Monitoring Cost-Effectiveness Analysis. Draft report prepared for Ruben Deza, U.S. EPA. Clean Air Markets Division, Washington DC. Prepared by The Cadmus Group, 6330 Quadrangle Drive, Chapel Hill.3 Task 1: Cost of Mercury Measurement Techniques

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Source Review (NSR) and New Source Performance Standard (NSPS) sections of the existing CAA (EPA, 2002i). Belo w, summaries are provided for Parts A, D, and E.

1.2.1 Common Provisions

The Clear Skies Act establishes a new Part A of Title IV of the CAA, which contains the program elements shared by the SO 2 , NO X , and mercury programs. A cap-and-trade program will be implemented for each po llutant. Common definitions, allowance system procedures, monitoring, permitting a nd compliance requireme nts, penalties for non-compliance, opt-ins and auction procedures apply to the new trading programs and are modeled largely after the existing Acid Rain Program.

Table 1-1. Projected Emissions Reductions under Clear Skies Act (EPA, 2002i.)

Actual emissions in 2000 Clear Skies Act emission caps Total reduction at full implementation First phase of

reductions Second phase of reductions

SO 2 (million tons) 11.2 4.5 (in 2010 1 ) 3 (in 2018 1 ) 73%

NO X 2 (million tons) 5.1 2.1 (in 2008 1 ) 1.7 (in 2018 1 ) 67%

Mercury (tons) 48 26 (in 2010) 15 (in 2018 1 ) 69%

Because sources can reduce emissions early, earn allowances for those actions, and use these allowances later, actual emission levels will be higher that the cap in the first years of these phases.
The NO X cap is divided between two zones with separate trading programs under each zone. Zone 1 generally includes Eastern states and Zone 2 includes Western states and territories.

The Administrator must establish an allowance system for SO 2 , NO X , and mercury that is essentially the same as the current Ac id Rain Program but provides for a safety valve, i.e., a direct sale of allowances by the Administrator at a fixed price for use in meeting the requirement to hold allowances at least equal to annual emissions. Criteria and the process will be established by which the Administrator may recommend to Congress adjustment of the total amounts of allowances available (whether through allocation or auction) starting in 2018 under the new SO 2 , NO X , and mercury trading

programs.4 Task 1: Cost of Mercury Measurement Techniques

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1.2.2 Mercury Emissions Reductions

The Clear Skies Act establishes Part D, whic h contains the new, annual caps on total mercury allowances and new, allocation pr ocedures starting January 1, 2010. The new mercury trading program is analogous to the new SO 2 and NO X trading programs and

cover the same coal-fired units. Annual mercury emissions are capped at 26 tons starting in 2010 and 15 tons starting in 2018. Each year, the percentages of allowances
allocated and auctioned are the same as under the new sulfur and NO X trading

programs.

1.2.3 Performance Standards for New Sources

To ensure that all new affected units have appropriate controls , Part E establishes performance standards for all new boilers , combustion turbines , and IGCC plants
covered under the Act. “New ” units are those that co mmence construction or
reconstruction after the date of enactment.

These statutory performance standards include emission limits for four air pollutants:
NO X , SO 2 , mercury, and particulate matter (P M). The mercury emission limit applies only to coal. In addition, a PM emission limit is established for existing oil-fired boilers
to ensure reductions of nickel from such units.

All units subject to a perfor mance standard must monitor emissions using continuous emission monitoring systems (CEMS) and us e averaging times similar to current
NSPS.

1.3 General Assumptions

The sampling program is assumed to be based on a single stack or single unit testing. No discount has been allowed for multiple si te testing at a plant or multiple plant testing. Multiple units being served by a common stack would be tested under a single sampling program.

For cost estimation, it is assumed that the plant will contract for OH sampling and analysis. Costs for the plant to administer the OH analysis program for Hg are based on5 Task 1: Cost of Mercury Measurement Techniques

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the Information Collection Requ est (ICR) supporting statement, 3 which assumes the following hours on a yearly basis:

 For obtaining an OH sampling cont ract, 40 technical hours.

 For oversight of OH sampling even ts, 8 technical hours per test.

 To compile and review analytical data , 8 technical hours per sampling event.

 To submit test results, 1 technical hour per event.

 For all technical work, asso ciated management hours have been assumed to total 5 percent of technical hours and clerical hour s have been assumed to total 10 percent
of technical hours.

Cost for plant labor hours have been assume d to be the same as used in the ICR Supporting Statement:

Technical hours $47.50, Management hours $57.27, and Clerical hours $26.96.

To estimate the cost associated with OH sampling, ARCADIS obtained three estimates for a sampling event of three OH runs at one location at a utility stack within 500 miles traveling distance from the sampling firm: $8,500, 4 15,000, 5 and between 12,000 and

3 “U.S. EPA, “Standard Form 83-1 Supporting Statement for OMB Review of ICR No._____:[ sic ] Information Collection Request for El ectric Utility Steam Generating Unit Mercury Emissions Information Collection Effort,” November 16, 1998. available at http://www.epa.gov/ttn/atw/com bust/utiltox/114_ss19.pdf.

4 Personal communication from Brian Jacobs, METCO Environmental, to Carl Singer, ARCADIS, on March 26, 2003.

5 Personal communication from Ge ne Stephenson, ARCADIS, to Carl Singer, ARCADIS, on March 11, 2003.6 Task 1: Cost of Mercury Measurement Techniques

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15,000 6 . The ICR supporting statem ent contained an estimated cost of $40,020 for
concurrent OH tests at two locations 7 . Consequently, costs for contracting for OH sampling and analysis are estimated at $15,000 per sampling event of three tests. It is
assumed that this number can be broken out as follows: $4,000 for travel and lodging of the OH contractor and $11,000 for the three- test event. This can be used to estimate

the costs of different sampling events. For example, a nine-test event would cost (3  $11,000) + $4,000 = $37,000.

6 Personal communication from Ralph Roberson, RM B Consulting, to Carl Singer, ARCADIS, on March 11, 2003.

7 “U.S. EPA, “Standard Form 83-1 Supporting Statement for OMB Review of ICR No._____:[ sic ] Information Collection Request for El ectric Utility Steam Generating Unit Mercury Emissions Information Collection Effort,” November 16, 1998. available at http://www.epa.gov/ttn/atw/com bust/utiltox/ 114_ss19.pdf7 Task 1: Cost of Mercury Measurement Techniques

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2. Ontario Hydro (OH) Analysis

2.1 Background

The ASTM recently issued the OH meth od under designation D6784-02 approved

April 10, 2002. The OH method is a gas sa mpling method that differentiates mercury into particle-bound, oxidized, and elemen tal fractions. The OH method was widely used as the basis for sampling plans und er the recent mercury ICR phase III.

2.1.1 Scope and Applicability

The OH method is applicable to the determ ination of elemental, oxidized, particlebound, and total mercury emissions from coal -fired stationary sources. Resulting emissions are expre ssed in concentration terms, μg/Nm 3 . Conversion of OH results into an annual mass emission will require application of additional methods.

Though the method explicitly claims applicability to coal-fired stationary sources, the method does not appear to exclude the use of other fuels such as coke, orimulsion, oil, tires, refuse derived fuel (RDF), or biomass. Use of alternate fuels may produce ash that may further confound speciation bias in the OH method but is not expected to effect total mercury.

2.1.2 Technique

The OH method involves extracting a flue gas sample through either a modified method 5 or method 17 sampling train. Sa mple location and traverse points are determined using Methods 1 or 2. Mercury is absorbed from the sample into various solutions in the train. The gas volume samp led is metered as the sample exits the sampling train. At the conclusion of an integr ated sampling event, the train is recovered generating analytical samples specific to particular mercury forms. The analytical samples are digested and analyzed in a laboratory.8 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

2.1.3 Accuracy and Precision

There are no known biases to the OH method for total Hg, however several conditions can affect the speciation of the sample. 8 The relative standard deviations for gas phase elemental and oxidized Hg were less than 11 percent for concentrations greater than 3 μg/m 3 and less than 34 percent for concentrations less than 3μg/m 3

. 9 A number of
revisions to the OH method have been made since the Method 301 evaluation cited in the OH method. The precision of the OH met hod is likely to have improved since the
initial Method 301 evaluation.

2.2 Assumptions

For the purposes of calculating total merc ury emissions, 12 OH sampling events are assumed with 3 OH tests required for each sampling event. The resulting 36 tests are expected to provide an accuracy of ±8.4%, similar to that expected from a nine-point Relative Accuracy Test Audit (RATA) for a CEMS.

For cost estimation, it is assumed that the plant will contract for OH sampling and analysis. Further, the sampling program is assumed to be based on each stack such that multiple units being served by a common stack would be tested under a single sampling program.

2.3 Capital Costs

An OH analysis program is likely to be ba sed on sampling after the particulate control device and is not expected to result in any significant capital costs. Current stack

8 D6784-02 Standard Test Method for Elemental, Oxidized, Particle-Bound, and Total Mercury in Flue Gas Generated from Coal-Fired Stationary Sources (Ontario Hydro Method), ASTM International, West Conshohoke n Pennsylvania, June 1, 2002.

9 ibid.9 Task 1: Cost of Mercury Measurement Techniques

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sampling locations are expected to be adequate for OH sampling and no system modifications will be required.

For purposes of estimation, it is assumed that plants will contract with sampling firms for OH sampling. Sampling firms are ex pected to supply their own sampling

equipment as part of their cost of doing business.

2.4 Annual Costs

2.4.1 Labor Costs

Costs for administering the OH analysis program are estimated using values from the ICR supporting statement. 10 The following technical hours have been assumed per

year:

 For obtaining an OH sampling cont ract, 40 technical hours.

 For oversight of 12 OH sampling events, 288 technical hours.

 To compile and review analytical data, 96 technical hours.

 To submit test results, 12 technica l hours have been assumed annually.

Total Technical hours for admini stration of the program is therefore expected to be 436 hours per year. Accordingly, labor costs for th e Hg analysis program at the stack level are estimated at $23,134 annually, includi ng management and clerical costs.

2.4.2 Subcontract and Other Direct Costs (ODC)

As indicated in Section 1.1.1 costs for co ntracting for OH sampling and analysis are estimated a $15,000 per sampling event of th ree tests. Subcontra cting and ODC costs

10 U.S. EPA, “Standard Form 83-1 Supporting Statement for OMB Review of ICR No._____:[ sic ] Information Collection Request for El ectric Utility Steam Generating Unit Mercury Emissions Information Collection Effort,” November 16, 1998. available at http://www.epa.gov/ttn/atw/com bust/utiltox/114_ss19.pdf.10 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

for an OH sampling program incorporating 12 sampling events is, therefore, estimated at $180,000 per year for each stack in the program.

2.4.3 Annualized Capital Costs

No significant capital costs are expected fo r an OH based monitoring plan. Annualized capital costs are therefore estimated at $0/year.

2.4.4 Total Annualized Cost

Total Annualized costs for th e OH emissions monitoring plan is estimated at $203,134.

2.5 Uncertainties

OH is presumed to be the reference method for potential mercury air emissions regulation. The draft perform ance specification for merc ury continuous monitoring systems cites 40CFR266, Appe ndix IX, Section 3.1. Use of different reference methods such as Method 29, Method 101A or Method 0060 are not expected to drastically affect the cost of each test, however, the monitoring program may require adjusting to achieve acceptable accuracy and precision.

The cost of an OH sampling program for determining emissions is largely driven by the frequency of sampling and the number of samples. For this analysis, we have assumed triplicate runs of OH on a monthly basis. Sites may require more or fewer samples to achieve the same confidence interval depending on the actual variability encountered. Variability is expected to arise from unit operation and method chosen for analysis. 36 OH runs were selected as a basis assuming a 25% relative standard deviation (RSD) and a desired c onfidence interval of ±8.4%.

An OH sampling program for determining emis sions relies on a repr esentative sample being collected. Such a program must be designed to collect a representative sample. Confounding factors may include changes in fuel, daily, weekly, and seasonal variations in operations, and ca tastrophic events. If there is significant serial correlation in mercury sampling, the number of tests may need to be increased to achieve the same
confidence interval.11 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

While it appears probable that an OH sampling program could be designed to provide
an accurate estimate of the amount of me rcury emitted from a stack, OH sampling may be inappropriate for an emission trading pr ogram. Specifically, it is doubtful that an OH sampling program could provide informat ion with the same timeliness as a Hg CEMS. With an OH sampling program, it woul d be difficult to identify changes in

emissions resulting from either operational or mechanical changes in the system; failure in a control system, such as a ca rbon injection system, would not likely be discernable using OH sampling. The applicability of an OH sample program is therefore likely dependent on other reco rds and a workable data substitution mechanism. Long intervals between sampling events risk compromising the credibility
of OH-based emissions estimates.12 Task 1: Cost of Mercury Measurement Techniques

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3. Carbon Trap Analysis

3.1 Background

The carbon sampling trap method is currently under further development in the U.S. It

is in the laboratory/pilot phase and is bei ng tested on a limited sc ale. No references were found that support that the met hod has been applied elsewhere.

Carbon trap sampling involves drawing a ga s sample through traps filled with a sorbent, generally activated carbon. Gaseous mercury present in the gas is adsorbed onto the carbon. The traps are subsequently removed from the sampling apparatus and shipped to a laboratory for analysis. For me rcury emissions monito ring, exposure of nominally one week is envisioned.

3.1.1 Preliminary Methods

Through literature research and industry c ontacts, two general carbon trap methods under development in the U.S. were iden tified. One method, using intermittent integrating technology coupled with Method 101A, is being designed by a team headed by Walter S. Smith and Associates, Inc., of Apex, North Carolina. The method is described by the developer as a prototype; technical specifics are not available, and no tests have been performed. 11 The second method is an adaptation by the Electric Power Research Institute (EPRI, “the manufact urer”) of a method th at was originally developed by scientists at Brooks Rand Limited and Frontie r Geosciences of Seattle, Washington, in 1991. 12 The earlier version of the method was identified as Mercury Speciation Adsorption (MESA). The most rece nt adaptation combines a larger version of the iodated carbon trap used with the MESA method and a specially designed gas meter and probe assembly to provide a cu mulative average mercury concentration for an extended period (1 week to 1 month). The EPRI method, the Quick Silver Emissions Monitor (QSEM), differs significantly from MESA, and no peer-reviewed

11 Personal communication from Walter Smith, Walter Smith Associates, Inc. to Michiel Doorn, ARCADIS, by email, June 26 and email June 24, 2003.

12 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email June 24, 2003.13 Task 1: Cost of Mercury Measurement Techniques

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publications are yet availabl e. The QSEM is currently undergoing testing in North Carolina and Missouri. Several groups are as sisting with the development of this
method under contract to EPRI: ADA Envi ronmental Solutions (ADAES) designed the sampling consoles and is currently coordina ting the testing efforts and subcontractor activities, Frontier Geoscience s provides the iodated carbon traps and conducts the trap

analysis, and Apex Instruments is curren tly providing the sampling hardware. Results from the Missouri/North Carolina field tests are expected in the near future. Additional testing is planned for late summer 2003. Dr aft Method Quality Objectives (MQO) for laboratory analysis of the iodated carbon traps for sorbent total mercury are included in
Table 3-1 below.

Further discussion will only cover the QSEM method. A recent modification (Model 2) includes an adapter to allow insertion of a smaller-diameter trap appropriate for a threehour test to allow for better comparison to an OH test. A draft operating manual for Model 1 is available from the manufacturer. Also available are two proprietary standard operating procedures (SOP). The first SOP addresses total mercury analysis by Cold Vapor Atomic Fluorescence Spectr oscopy (CVAFS) and is a modified version
of EPA Method 1631E. The second SOP is en titled “Digestion for Gas/Air Samples Collected on Iodated Carbon Traps for To tal Mercury Analysis” and is a peerreviewed, published method. A recent change to this SOP consists of shipping the traps with gloves to be worn by personnel that work with the tr aps, to minimize
contamination. 13

Table 3-1. Draft MQO for Sorbent Total Mercury by internal Frontier Geosciences Method

QA Measurement MQO Value
Laboratory Replicate ± 25% RPD
Laboratory SRM Spike Recovery 100 ± 20%
Lab Analysis Matrix Spike Recovery 100 ± 20%
Field Sample Spike Recovery 100 ± 30%
Field Sample Duplicate ± 30% RPD

Method Detection Limit 0.05  g/m 3 @ 30 liters 0.002  g/m 3 @ 1500 liters

13 Personal communication from Sharon Sjostrom, ADAE S, to Michiel Doorn, Carl Singer, and Brent Hall, ARCADIS, July 7, 200314 Task 1: Cost of Mercury Measurement Techniques

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Advantages of the carbon trap method in clude ease of oper ation and a simple technology. The method can be cost effectiv e, depending on verification requirements. The main disadvantage is th at the method provides a delayed, “blanket” cumulative average without the possibility to identify peaks or periods with minimal emissions. Because continuous information may prove ne cessary for timely response to control

device operations, this could be a very important disadvant age. The method is neither real-time, nor continuous and, furthermore, is still in the development stages. In addition, only one manufacturer in the U.S. ca n currently offer a pilot-test-ready device or the treated traps.

3.1.2 Scope and Applicability

Once the carbon trap method has reached commer cial status, it should be applicable to capturing total mercury with 100 percent effici ency from coal-fired stationary sources. The method takes a continuous, cumulative sa mple over a given time period that can range from one hour to one week and possibly up to a month. After this time period the trap is exchanged for a fresh one, and the used tr ap is sent to an off-site laboratory to be analyzed according to standard methods. 14

For use in wet, saturated environments, the manufacturer has designed a modified tip for the trap to minimize wetting by large dr oplets, as well as a heated carbon trap to avoid operational difficulties due to the poten tial high pressure drop across the trap. This modified design ha s not yet been tested. 15

3.1.3 Technique

The carbon trap technique us es 6 mm or 10 mm diameter cylindrical traps containing activated carbon impregnated with potassium iodide to adsorb mercury from flue gas. The sampling system consists of a sample probe, Teflon ® tubing, a glass wool plug to collect PM, a two-part sorbent trap, a sample pump, and a gas meter mounted in a

14 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email June 24, 2003.

15 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email June 24, 2003.15 Task 1: Cost of Mercury Measurement Techniques

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console. The front section of the sorbent trap is used to chemically adsorb mercury. The back section, separated from the front by glass wool, collects any mercury that breaks through the front section. The flue gas is extracted through the carbon-packed trap where the Hg is adsorbed. The sample pump mounted in the console, along with a flow meter and temperature gauges, create s the vacuum on the carbon trap. The flow

meter can be adjusted to achieve any desi red flow rate through the sampling system according to the time period of sampling a nd the flow rate of the stack gas. Typically, the carbon trap and the probe that secures it are the only things extending into the flue gas path. Once the sample has passed the probe and carbon trap, it travels through a heated Teflon line to prevent condensation of any moisture that may build up and cause operational difficulties. The sample then travels through a water knockout and drying
column where the moisture is removed be fore passing through the sample pump and gas meter.

Experiments by the manufacturer have show n that the carbon captures both elemental and oxidized mercury with 100 pe rcent efficiency over at l east one week for flue gas concentrations typical of coal-fired power plants. 16 The sampling system can be modified to sample isokinetically for partic ulate mercury as well as gas phase mercury. In the current application, the sampli ng system has been designed to exclude particulate Hg collection. However, some in cidental PM may collect on the glass wool plug prior to the carbon bed. A separate anal ysis has indicated that particulate Hg is less than 1 percent of total Hg in gas stream s after a particulate control device, which is similar to results reported by the OH Method. 17

The system currently operates by drawing gas continuously through the trap at a constant rate. The samples are typically colle cted for a week, at which time the carbon trap is removed, sealed, and shipped to an analytical laboratory, where the mercury is leached from the carbon using a strong acid and subsequently analyzed with Cold Vapor Atomic Absorption Spectroscopy (CVAAS).

16 Personal communication from Eric Prestbo, Frontier Geosciences, Inc. to Michiel Doorn, ARCADIS, email June 25, 2003

17 Ibid.16 Task 1: Cost of Mercury Measurement Techniques

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Research is underway to develop a propor tional sampling approach. The new consoles being used incorporate a barometric pressure sensor, a digital manometer, and a flow control valve. The sampling consoles are de signed to monitor the duct flow using a standard pitot connected to the digital mano meter. Upon installation, the operator can configure the sampling console to use either the duct flow measured by the pitot, or an

external 0-5 volt signal (such as stack flow from the CEMS, or boiler load) to control the sample rate set point. The micro contro ller in the sampling console automatically adjusts the sample flow rate based upon the set point signal. The association of the control signal (i.e. digital manometer, stack flow, load, etc.) to the sample flow set point can be defined by the operator. 18

3.1.4 Accuracy and Precision

The carbon trap is analyzed in an off-site laboratory. Currently, the only laboratory that analyzes these traps is Frontier Geoscience s. The quantity of mercury is measured using a method with a detection limit of 0.5  g/L (5 ppt) in the leachate. Frontier
Geosciences estimates that this detection limit is equivalent to about 1  g/m 3 for a oneweek sampling period. 19 In addition, Frontier Geosciences maintains that they can easily match the OH Method for total mercury. 20

There is data available from the MESA method indicating very good accuracy and precision. This method employed a solid tr ap upstream of the activated carbon to capture oxidized mercury. Frontier Geoscien ces suggests that the new Iodated Carbon Traps should perform similarly to the carbon portion of the MESA traps and that data should be comparable. Recent tests with Iodated Carbon Traps suggest very good precision in the laboratory analysis. Th e manufacturer is using components from standard sampling equipment (i.e. calibrated dry gas meters) and expects the total flow

18 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email June 24, 2003.

19 Personal communication from Eric Prestbo, Frontier Geosciences, Inc. to Michiel Doorn and Carl Singer, ARCADIS, May 30, 2003

20 Personal communication from Eric Prestbo, Frontier Geosciences, Inc. to Michiel Doorn, ARCADIS, email, June 24, 200317 Task 1: Cost of Mercury Measurement Techniques

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recorded during each sampling run to be w ithin acceptable accuracy. In addition, the manufacturer is currently conduc ting tests to assess the prec ision and accuracy of the current equipment and carbon traps by ru nning duplicate simultaneous samples in conjunction with OH testing.

3.2 General Assumptions

For the purposes of cost estimation, it is a ssumed that the method will be developed in adequate detail for EPA to include carbon traps as an acceptable method of determining annual total merc ury emissions. We further assume carbon traps will typically sample for one week consistent with the current design strategies. A range of sampling strategies may prove viable; each with QA/QC adequate to demonstrate annual emissions accuracy.

Since the currently proposed carbon trap te chniques utilized fixed point sampling,
similar to other CEMS measur ements covered in Part 75, it is assumed that a QA/QC program will be required to ensure representativeness a nd accuracy for carbon trap measurements. The reference method for mercury is assumed to be the OH method. While a RATA of carbon traps sampling for on e week does not appear practical due to widely differing sampling times with OH, a RATA of carbon traps sampling for 3 hours, using an adapter and smaller traps, is assumed to be adequate for determining representativeness and accu racy. For costing purposes, an annual 9-sample RATA against OH is assumed.

In addition to a RATA, it is assumed that some QA/QC program will be implemented

to ensure accurate emission estimates are made throughout the year. For cost estimating purposes, the QA/QC program will consist of 4 quarterly checks of each sample gas metering system and 3 quarterly matrix spike checks. The fully developed carbon trap technique is assumed to provide proportional sampling of the stack gas; auditing of proportionality is assumed to be integral to the monitoring system. Accuracy of the total sample volume measurem ents is expected to be confirmed with quarterly calibration of th e sample gas metering system. It is assumed that Hg concentration accuracy will be confirmed with some fo rm of spiked carbon trap analysis. For costing purposes, it is assume d that mercury spiked carbon traps will be available and will sample flue gas in para llel with an unspiked carbon trap over the typical one-week sampling peri od. It is further assumed th at an unexposed carbon trap will be analyzed as a blank on a quarterly basis.18 Task 1: Cost of Mercury Measurement Techniques

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It is assumed that carbon trap sampling will be performed in dupl icate. If the QA/QC validating carbon trap based em ission measuremen ts is performed on a quarterly basis, failure to meet QA/QC objectives could invalidate a large portion of the annual
emissions measurement. Replication is one method of ensuring against the need to use currently undefined data substitution. Duplicatio n is therefore expected to represent the

minimum application of replication adequa te for QA/QC requirements and reasonable data invalidation protection. Assumed annual requirements for carbon trap emission
measurements are summarized in Table 3.2

Table 3.2: Assumed Carbon Trap Analytical Summary
Carbon Trap Requirements Other QA/QC Requirements
RATA 9 3-h traps + 1 weekly tube 9 OH runs + 2 gas meter cals
12 weeks 24 weekly traps
QA/QC check 1 3 weekly trap s: matrix, matrix spike, blank 2 gas meter cals

12 weeks 24 weekly traps
QA/QC check 2 3 weekly trap s: matrix, matrix spike, blank 2 gas meter cals

12 weeks 24 weekly traps
QA/QC check 3 3 weekly trap s: matrix, matrix spike, blank 2 gas meter cals

12 weeks 24 weekly traps
Annual Total 9 3-h traps + 106 weekly traps 9 OH runs + 8 gas meter cals

Travel expenses associated with installation, training, and maintenance by the manufacturer are not included. Travel expenses associated with the RATA are included in the cost of subcontracting.

3.3 Capital Costs

Capital costs for a carbon trap system (s ampling console, probe, water knockout assembly) is approximately $8,500. 21 Installation costs (for equipment location, setup,

21 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email June 24, 2003.19 Task 1: Cost of Mercury Measurement Techniques

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electrical hook-up and probe insertion) are estimated to require two hours of technical labor for a total labor cost of $106 per car bon trap system. As two carbon trap systems are assumed, total capital co sts are estimated at $17,212.

3.4 Annual Costs

3.4.1 Labor Costs

This section addresses annual labor costs fo r the plant. The following technical hours
are estimated to be a ssociated with this method on an annual basis:

 For operations, 4 hours per week per carbon trap system, to rem ove the used trap, install a new trap, mail the used trap to the manufacturer (or other future laboratories/providers), and comp lete associated paperwork.

 For routine checks, 3 hours per week per ca rbon trap system (8 minutes per 8-hour shift).

 For carbon trap flow calibration, 2 hour s per quarter per carbon trap system

Accordingly, it is estimated there are 744 te chnical hours asso ciated with operation of two carbon trap systems.

It is assumed that awarding a contract for carbon trap analysis will require eight
technical hours. It will also re quire eight hours to compile an emissions report. As this
will occur four times annual ly, it will result in an additi onal 32 technical hours. Finally, it will require one technical hour to submit th e report, but again, this will occur four times annually, resulting in another four hour s. This results in 44 technical hours for reporting, or $2,334 annually, including ma nagement and clerical labor. Routine operations are therefore estimat ed to require 788 technical hours annually for a cost of $41,812 including management and clerical costs.20 Task 1: Cost of Mercury Measurement Techniques

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Plant labor associated with RATA testing is estimated to require 121 technical hours. It will require 40 hours to obtain a contract for RATA testing, 72 hours for oversight of nine tests, 8 annual hours to co mpile and review analytical data, and 1 hour annually to
submit test results. Plant labor costs for verification testing ar e estimated at $6,420

Thus, combined labor costs for routine operation and verification are estimated at $48,232

3.4.2 Subcontract and ODC

Basic analytical costs performed by the manufacturer to analyze and replace one carbon trap are $200. 22 These costs include packing the traps with gloves for sample handling (installation and rem oval), data collection and chain of custody forms, and post-test analysis. These cost s do not include any additional analyses, and the special tip for wet-stack applications. For cost estim ation purposes, all traps; 3-h, weekly, or spiked, are assumed to cost the same $200 for complete turnaround. In addition to the above, $20 per week is assumed for shippi ng and handling (two ways). Based on the assumed 115 annual trap requirement, anal ytical costs are estimated at $24,040 annually.

A nine-test OH sampling event is esti mated to cost $37,000 to subcontract.

Estimated total s ubcontracting costs and ODC are $61,040.

3.4.3 Annualized Capital costs

Based on a three-year straight-line depreciation, annualized capital costs are estimated at $5737.

3.4.4 Total Annualized Costs

Total annualized costs for mercury emissions determina tion with the carbon trap method are estimated at $115,009.

22 Personal communication from Sharon Sjostrom, ADAES, to Michiel Doorn, ARCADIS, by email, June 24, 2003.21 Task 1: Cost of Mercury Measurement Techniques

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This may be compared to the preliminary cost estimate submitted for the prototype by
Walter S. Smith and Associates. No tests have been performed, but total annual costs, including a lease, are estimated to be less than $50,000. Tec hnical specifics are confidential at this point. 23 Assuming this technique woul d be performed in duplicate and would require a RATA as well, total annual costs for the Walter S. Smith and

Associates monitoring technique would be less than $137,000.

3.5 Uncertainties

Application of carbon traps fo r mercury emissions measurem ents will be dependent on continued development and acceptance of the technique as a method. Methods are often validated against various spiking tec hniques or against a standard method. EPA acceptance may require such validation on multiple so urces, depending on how EPA views source categories.

Implementation of carbon traps for merc ury emissions will likely require the development of QA/QC procedures and limi ts as part of publis hed procedures. The procedures to be defined include:

 Leak-check documentation and limits

 Sample metering calibration

 Proportional sampling validation

 Chain of Custody

 Back-half capture limits

 Laboratory calibration, conti nuing calibration verificati on, independent calibration
verification

 Laboratory duplicates

23 Personal communication from Walter Smith, Walter Smith Associates, Inc. to Michiel Doorn, ARCADIS, by email, June 26 and email June 24, 2003.22 Task 1: Cost of Mercury Measurement Techniques

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 Blanks

 Carbon tube analytical hold times.

In addition, methods to audit both sample collection and analysis are likely to be

crucial to acceptance of the technique. One route to auditing both collection and analysis is the development of a standard technique to spike mercury onto a carbon trap. Techniques for spiking the carbon traps, either in the field or in the laboratory, have been implemented by method developers.

The effectiveness of the carbon traps depends on various parameters, such as sorbent properties, coal type, flue gas conditions a nd composition, and reaction kinetics. These conditions will vary with site config uration and coal composition. Although the method does not distinguish between the elem ental and oxidized forms of mercury, the efficiency of adsorption for both oxidized and elemental mercury must be validated over a variety of stack conditions, as well as fly ashes. One method of validation would be analysis of duplicates samples, one collected on a clean carbon trap and one collected on a mercury spiked carbon trap.23 Task 1: Cost of Mercury Measurement Techniques

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4. CEMS Analysis

4.1 Background

Hg CEMS are undergoing continuing develo pment, with current technology being

tested under various programs. Few, if any, applications at coal -fired power plants currently exist in the United States, but the technology is developing rapidly. Many CEMS have been undergoing field tests, and some have participated in several. Most manufacturers are in the proc ess of making significant impr ovements or refinements to their monitors as time proceeds. Consequently, the CEMS information in this report, and similar reports, may need to be upd ated in the relatively short term.

In Germany, automatic mercury sampling de vices have been applied since the early 1990s. The Federal Republic of Germany issued regulations for both emission limits and continuous monitoring of total mercury in incinerator flue gases. Under the regulation, CEMS need certification fo r approval. The German emission limit of 0.05 μg/m 3 was adopted for the European Union in 1994. 24

CEMS can be classified according to th eir method of converting oxidized Hg to elemental Hg as dry or wet. Wet systems convert Hg in impinger solutions, while dry systems thermally or catalytically conver t the Hg species. Most CEMS can provide speciated Hg emissions values, but the development trend in industry is toward total Hg measurement.

Based on operational experience and indust ry knowledge, the dry systems appear to offer more operational availability and re quire less maintenance compared to wet systems. They provide quick real-time Hg c oncentrations and many have inherent auto zeroing and system checks built into them . The dry systems are easier to operate overall and offer a more reliable Hg numb er because of not having any chemical interactions. The disadvantages of wet sy stems include increased maintenance and potential problems with the gas conditioning systems malfunctioning. Also, the

24 Sigl, W., 2000. Continuous monitoring of mercury emissions in combustion flue gases with the Hg-CEMS 'MERCEM'. In “Recent advances in the science and management of air toxics”, Proceedings of the joint internat ional specialty conference, exhi bition and workshop of the Air and Waste Management Association, 9 - 12 April 2000, Banff, Canada.24 Task 1: Cost of Mercury Measurement Techniques

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solutions used in wet systems may react w ith flue gas components in unexpected ways. Another disadvantage of current wet syst ems is that they only yield a mercury concentration every 4-6 minutes, dependi ng on the cycle set up; they are not truly “continuous” Hg monitors. For the purpose of further discussion, only the dry systems

are addressed.

It is apparent through the results from e ach subsequent field evaluation that the reliability and accuracy of Hg CEMS has gr eatly improved. Hg CEMS are viewed as a viable choice for Hg monito ring because of the continuous data delivery, as well as their improving accuracy. It is anticipated that Hg CEMS would be a preferred method of Hg monitoring, provided the costs ar e comparable to othe r viable methods.

For this report and other recent associated draft reports, techni cal, performance, and cost information was requested from 12 ve ndors. Eleven vendors provided technical and performance information, while seve n manufacturers responded with cost
information. Table 4-1 summarizes techni cal information of 12 different Hg CEMS. Table 4-2 includes performance information related to operation and maintenance. All data in Tables 4-1 and 4-2 are from manufacturer responses.

4.1.1 Scope and Applicability

There is currently no regulatory driver or performance standard for CEMS; although a draft performance standard has been developed 25 against which Hg CEMS can be evaluated. However, quality requirements can not be fully defined at this point. A regulation for Hg could, conceivably, requ ire monitoring of elemental, oxidized, or total Hg, resulting in different potential equipment needs.

Hg CEMS could find wide use for monitoring flue gas emissions at coal-fired power plants. As indicated earlier, there is widespread use of Hg CEMS in Europe, but mostly at municipal, or medical waste incinerators.

25 Draft Performance Specification 12 – Specifications and test procedures for total mercury continuous monitoring systems in stationary sources. http: //www.epa.gov/ttnemc01/propperf/ps12.pdf25Task 1: Cost of MercuryMeasurement TechniquesDraft Report, Revision 1Table 4-1. Overview of Mercury CEMs that are (expected to be) Commercially Available in the United StatesModel Principles of operation Speciation Interferences Zero Drift Calibration DriftRelativeAccuracyFieldApplicationUSDetectionLimitSampling/Response timeCooperX-CMMX-ray fluorescence Total noneNo zeroadjustment isnecessaryCalibrationevery fewmonthsna na0.1g/m310-20 minDuragHM-1400 TRDual-Beam CVAASTotal andElementalNone below1500 ppm SO2< ±1.5% F.S.per week< ±2 % F.S.per week± 5% F.S.(totalaccuracy)none <1 mg/m3180 sEcochemHG - MKIICVAAS with goldtrapTotal andElementalnoneUses presetintervals withalert systemNo information na none na naEnvimetricsArgus-HgPlasma sourcespectrometerElemental,OxidizednaNo zeroadjustment isnecessaryAutomaticcalibration withbuilt-in Hgstandardna na0.03g/m3naGenesisQuicksilverSky MonitorDry methodParticulate,Oxidized,Elementalna naNo errors,proprietarytechnologyna na na naNippon26AM-2/ AM-3CVAAS with goldtrapElementalCl2and to alesser extentHClHg00.96g/m3Hg02.93g /m3Hg018%Hg016%Hg014%Hg023%none0.1g/m35-13 min26Nippon Instruments Corporation Model AM-2 Elemental Mercury Continuous Emission Monitor;Environmental Technology VerificationReport. U.S. Environmental Protection Agency in cooperation with Battelle, Inc. August 2001.26Task 1: Cost of MercuryMeasurement TechniquesDraft Report, Revision 1Model Principles of operation Speciation Interferences Zero Drift Calibration DriftRelativeAccuracyFieldApplicationUSDetectionLimitSampling/Response timeNippon27MS1/DM5CVAAS and wetscrubbing pluschemical for total HgElementaland OxidizedHCl‘0.1g/m3‘0.1 ug/m3‘0.1g/m3‘0.1g/m3Hg014%Hg+213%Hg012%Hg+211%HgT13%Hg011%Hg+255%HgT39%Hg049%Hg+250%none0.1g/m3Ionic Hg 60 s.Detector 35-50 s.Ohio Lumex28CVAAS, withZeeman highfrequencypolarizationbackgroundcorrectionTotal andElementalHCl and Cl20.20 HgT0.37 Hg02.45 HgT0.17 Hg062% HgT92% Hg024% HgT18% Hg0HgT58%Hg050%Hg+299%HgT71%Hg0107%Hg+269%none na 20-48 s27Nippon Instruments Corporation Model MS-1/DM-5Elemental Mercury Continuous Emission Monitor;Environmental TechnologyVerification Report. U.S. Environmental Protection Agency in cooperation with Battelle, Inc. August 2001.28Lumex Ltd. Mercury Continuous Emission Monitor;Environmental Technology Verification Report. U.S. Environmental ProtectionAgency in cooperation with Battelle, Inc. August 2001.Table 4-1 continued.27Task 1: Cost of MercuryMeasurement TechniquesDraft Report, Revision 1Model Principles of operation Speciation Interferences Zero Drift Calibration DriftRelativeAccuracyFieldApplicationUSDetectionLimitSampling/Response timeOpsisHG200Dual beamabsorptionphotometerTotal andElementalSO2may beissuena na naTwo testsites0.5 pg 8 minPSAnalytical29Sir Galahad IIAtomic fluorescencewith gold trapTotal,Oxidized, andElementalElemental: Cl20.003g/m30.013g/m312%11%HgT21%Hg023%Hg+227%HgT33%Hg030%Hg+233%18 units,mainly forresearch0.1 pg 6 minST2SM-3CVAAS Total SO2< 1g/m3after 1week of testingSee TüVreportSee page38 of TüVreportnone na naTekranAtomic fluorescencewith gold trapTotal andElementalNoneOn-lineautomated zeroand multi-levelspan checksAutomaticrecalibrationusing internalpermeationsourcena none<0.05g/m32.5 minna = not applicable29PS Analytical Ltd. Sir Galahad II Mercury Continuous Emission Monitor;Environmental Technology Verification Report. U.S.Environmental Protection Agency in cooperation with Battelle, Inc. August 2001.Table 4-1 concluded.28Task 1: Cost of MercuryMeasurement TechniquesDraft Report, Revision 1Table 4-2. Operation & MaintenanceModel Principles of operation Operation continued Conditioning System Filter Trap OtherCooperX-CMMX-ray fluorescence Works with filter tapeNo pre-treatmentnecessaryAutomatic NoNo calibrationgases neededDuragHM-1400 TRDual-Beam CVAAS navHeated lines;Thermo-catalyticconverterParticle filterGold trap; Cleaned1x/day by heat;Aromatics, SO2, NO2are interferencesNH3can causeflow problemsEcochemHG - MKIICVAAS with gold trap navTeflon or heatedparts; Dry catalyticdevicenavGold trap; Desorptioninto pure N2navEnvimetricsArgus-HgPlasma source spectrometer No chemical reagentsSolid catalyticconverter; Peltiercoolingnav --Automatedcalibration;Maintenance onlyevery 6 monthsGenesisQuicksilver SkyMonitorDry method SOXremoval by scrubbing -- nav --Calibration 1x peryear; Tradesecret forbackgroundcorrectionNipponMS1/DM5CVAAS and wet scrubbingplus chemical for total HgnavDistilled waterscrubber;Dehumidifier; TwocoolersDust filter,membranefilterGold trap/Heater; Needspurified airnavOhioLumexCVAAS, with Zeeman highfrequency polarizationbackground correctionTwo-channel instrument“Pyrolyzer”converterParticle filterand zero HgabsorptionfilterNo gold trapCharge battery;Manual availableon-line29Task 1: Cost of MercuryMeasurement TechniquesDraft Report, Revision 1Model Principles of operation Operation continued Conditioning System Filter Trap OtherOpsisHG200Dual beam absorptionphotometernavDilution system;Dry thermocatalytic converter;Coolernav Gold trapTwo calibrationgasesPS AnalyticalSir Galahad IIAtomic fluorescence with goldtrapConverts Hg into Hg0withaqueous reagentScrubber; Tubingand agentsreplaced every 2weeksFilterGold trap, Preconcentration trap;Needs argon gasHeateddiaphragm pump;Built in calibrationST2SM-3CVAAS nav nav nav No carrier gasMaintenance freepumpTekranAtomic fluorescence with goldtrapInert probe, dry converter nav nav Gold trapMaintenance 1-4hours per 4weeks; Built inautomaticcalibrationnav = not available or not provided by the vendorTable 4-2 concluded.30 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

4.1.2 Technique

EPA defines the CEMS as “The total equipment required for the determination of a pollutant concentration. 30 ” Total equipment includes the major sub-systems such as the

sampling interface, pollutant analyzer, diluent analyzer, and data recorder.

Mercury CEMS typically measure only Hg 0 using some varia tion of CVAAS or CVAFS. Many incorporate a pr ocess that converts gaseous ionic Hg to gaseous Hg 0

, resulting in measurements of total gaseous Hg . PM is typically filtered from the sample before analysis, which remo ves particle-bound Hg. This process therefore results in underestimates of total Hg; it also may cause bias in speciation and bias in total gaseous Hg. Some fly ashes react with Hg, resulting in the oxidation of Hg 0 in the probe and on filters, which in turn overesti mates ionic Hg. Fly ash may also adsorb or desorb Hg, which biases estimates of to tal gaseous Hg because the ash is not subsequently analyzed for Hg.

The measurement techniques used by CEMS are often affected by common coal combustion contaminants. The draft performan ce specification lists eight potentially interfering components: carbon monoxide, ca rbon dioxide, oxygen, sulfur dioxide, nitrogen dioxide, water vapor, hydrogen chlo ride, and chlorine. Such interferences are often dealt with in a manner specific to each CEMS. One common mechanism is to amalgamate the Hg on a gold trap and regene rate the mercury captured on the gold trap into a carrier gas that is then analyzed.

4.1.3 Accuracy and Precision

Evaluation of Accuracy and Precision of Hg CEMS is confounded by the rapid and continuing development of Hg CEMs by ve ndors and the lack of published information on CEM performance. Evaluation of the pe rformance of CEMs will improve when suitable reference materials or procedures become available. A National Institute of

30 Draft Performance Specification 12 – Specificati ons and test procedures for total mercury continuous monitoring systems in stationary sources . Website: http://www.epa.gov/ttnemc 01/propperf/ps-12.pdf

.31 Task 1: Cost of Mercury Measurement Techniques

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Standards & Technology (NIST) approved el emental mercury gas standard is still under development. EPA has developed a dr aft performance specification, PS-12, which defines relative accuracy requireme nts for Hg CEMS measurement along with certain other QA requirements; a relative accuracy of 20% is currently specified in

PS-12.

EPA’s Office of Research and Development conducted Relative Accuracy tests on four Hg CEMs under the Environmental Test Ve rification (ETV) prog ram in January 2001. The ETV program was created to facilit ate the use of innovative environmental technologies [including co ntinuous emission monitors (CEM)] by testing their performance and making the results availa ble to those involved in their design, distribution, permitting, purchase, and use. These ETV tests were performed on a pilotscale natural gas-fired combustor. 31 As shown in Table 4-1, a vintage 2001 Nippon CEMs was able to achieve 13% relative accuracy during the ETV tests.

Six Hg CEMs were also recently evaluate d under the ETV program at a Department of Energy (DOE) Toxic Substances Control Act (TSCA) incinerator in Oak Ridge, Tennessee; this source cate gory was not pursued as a source of CEM data due to expected differences in the flue gas comp osition. Results from the TSCA incinerator were presented at the Air and Waste Management Association (AWMA) conference in San Diego. 32

EPA’s Office of Air Quality Planning and Standards (OAQPS) is undertaking a series of field tests of several mercury CEMs at co al-fired power plants. The first series of Relative Accuracy tests at a full-scale coal-fired powe r plant were conducted in October 2002 but are not yet published. OA QPS is currently conducting two Hg CEM
demonstrations/evaluations at full-scale coal-fired power plants. The results of these tests are expected to be available in October 2003. EP RI recently published CEMs

31 Environmental Technology Verification Program. Website: http://www.epa.gov/etv/verifications/vcenter1-11.html

32 Dunn, J.E., et al. 2003. Evaluation of Mercury Continuous Emission Monitors at the U.S.
DOE TSCA Incinerator. AWMA, 96 th Annual Conference, June 22-26, 2003, San Diego, CA.32 Task 1: Cost of Mercury Measurement Techniques

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measurements of Hg emissions at several coal-fired power plants; QA information regarding the performance of the CEMs was not found in the paper. 33

4.2 General Assumptions

 A three year, straight-line write-off for capital costs is assumed.

 Capital costs do not include installation costs.

 Technician training is assumed to be include d in capital costs.

 Costs for utilities (water, electricity, heat, cooling) are not included.

 Calibration costs have not been included, pending guidance from EPA. None of
the manufacturers submitted ca libration cost information.

 Because of the trend in the industry, onl y systems that can measure total Hg are considered. This includes systems that can do both total and elemental Hg.

 The trend in the industry seems to be to ward dry systems. The labor, sampling and analysis costs reflect estimates for dry syst ems only, while the capital cost analysis includes all systems.

Similar to the performance verification of SO 2 monitors, it is assumed that the plant would perform one RATA annually using the OH method, consisting of nine (9) tests, as well as perform three (3) cylinder audits on the Hg CEMS. The cylinder audits are assumed to be performed by the plant. A cy linder audit would typically require using a certified gaseous elemental Hg standard and introducing th is gas through the probe or directly to the detector and the entire sampling system. This would facilitate determining if there were a ny bias being imparted by the sampling systems as opposed to the detector. It is assumed that the cyli nder audits could be performed by the plant personnel with the procurement of a gas standard.

33 Chu, Paul, et al., Characterization of “Longer Term” Me rcury Emissions from Coal-Fired
Power Plants , 2003 MEGA Symposium, Washington, DC.33 Task 1: Cost of Mercury Measurement Techniques

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4.3 Capital Costs

Capital costs for CEMS that are available on the U.S. market, or that are expected to be available soon, are listed in Table 4-3. This information was collected through an email request and ensuing telephone conversations with individual vendors. Costs have been

standardized to the extent possible to reflect a complete CEMS and to exclude installation. Capital costs are especially de pendent on the configuration of the system. Also, the systems differ in both basic and ancillary su pporting technology. For several vendors, these costs are preliminary.

Table 4-3 includes 15 entries representin g CEMS from 11 manufacturers. When a manufacturer provided a large range for capita l cost, as was the case with Genesis and OhioLumex, both the low-end and the high-end estimate were included in the table and in the summary calculations. In other words, the submittals were regarded as separate instruments. The Nippon MS-1A instrument was excluded because it can not measure total mercury.

Table 4-3. CEMS Capital Cost (March 2003)

Vendor Name Model Capital Cost Notes Mercury System Type
Dry Systems:
Cooper Environmental Services X-CMM $100,000 Estimate for complete system. Filters would cost around $5,000 per year. Total Dry, uses filter

tape

Durag HG-1400 TR $45,000 Does not include heated sample line. Heated probe of $3,000 is optional. Speciating Dry

Ecochem HG-MKII $59,400 -- Speciating Dry

Envimetrics Argus-Hg 1000 $54,200 Estimate. Includes sample probe, heated sample line and controller. Speciating Dry

Genesis Laboratory Systems Quicksilver Sky Monitor $35,000 Estimate for CEM ($20,000) plus low-end gas conditioning system. Speciating Dry

Genesis Laboratory Systems Quicksilver Sky Monitor $85,000 Estimate for CEM ($20,000) plus high-end, specialized gas conditioning system. Speciating Dry34 Task 1: Cost of Mercury Measurement Techniques

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Vendor Name Model Capital Cost Notes Mercury System Type

OhioLumex CEM $40,000 Low-end estimate. “CEM, based on AA with Zeeman correction for interferences, dry converter system, total

Hg, detection limit- 0.1 μg/dscm. Installation is not included.” Speciating Dry

OhioLumex CEM $60,000 High-end estimate. Speciating Dry

Opsis HG200 $80,000 Basic instrument: $30k, Basic instrument (30k) with converter ($50k) and conditioning system. Speciating Dry

ST2 Service Technologies SM-3 $47,666 Complete system, simple probe. Total Dry

Tekran $85,000 Preliminary estimate Speciating Dry
(Semi-)wet systems
Nippon Instruments DM-6 $38,000 Standard gas generator and KOH scrubber an optional Speciating Semi-dry

Nippon Instruments DM-6A $34,000 -- Speciating Semi-dry

PS Analytical Mercury CEM $80,000 Low-end estimate. “The PS Analytical Mercury CEM can be configured in a number of ways using its stream selection capability. Systems include the unique calibration device.” Speciating Wet

Not considered:
Nippon Instruments MS-1A $13,000 Not including probe unit Elemental Semi-dry

The average capital cost of the speciatin g and total Hg CEMS is $60,233, while the median value is $56,800. The lowest va lue is $35,000 and the highest value is35 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

$100,000. Additional information, such as copies of correspondence with manufacturers and copies of quotations may be found in a draft EPA report. 34 In the ensuing cost calculations, the average capital cost of $60,233 is used.

4.4 Annual Costs

4.4.1 Annual Labor Costs

Based on the ARCADIS expert review and review of the data submitted by the vendors, a yearly technical la bor allocation for dry systems of 219 hours is estimated. This number is built up of one 10-minute insp ection per shift, three shifts per day, and 365 days per year, as well as three hours of maintenance per month. Thirty-two
technical hours are as sumed for compiling and validating four quarterly emissions reports. Four additional hours are estimate d for submission of these four reports. Routine operations of Hg CEMs are therefor e estimated to require 255 technical hours.

As mentioned, three cylinder audits per ye ar are assumed. Four technical hours are estimated for the performance of a single cyli nder audit and to prepare a report, a total of 12 hours per year. Additional labor costs as sociated with the performance of three cylinder audits is therefore estimated at $637.

Plant labor costs associated with relative accuracy verification testing (one events with nine tests) are estimated to be 121 technical hours including:

 40 hours for OH contacting

 72 hours for OH oversight

 8 hours for report review

 1 hour for report submission

34 EPA, 2003. Cost of Mercury Measurement Techniques. Draft Report submitted on March 28, 2003, by Perrin Quarles Associates, Inc.36 Task 1: Cost of Mercury Measurement Techniques

Draft Report, Revision 1

Including managerial and clerical suppor t. the labor costs for the verification component for this program ar e estimated to be $6,420.

4.4.2 Subcontract and ODC

Based on the expert review and review of the data submitted by the vendors,
ARCADIS estimates an annual material s operations and maintenance budget associated with sampling and analysis for a generic dry CEMS of $2,500. This budget includes the cost for replacement parts, including the catalyst, tubing, pumps, and fittings. Because many CEMS are still in th e pilot stage and the technologies are often proprietary, this estimate is preliminary.

It is assumed that the procurement of the gas standard associated with the three cylinder gas audits the standard would cost $5,000 annually. 35

One nine-test OH RATA is estimated to cost $37,000 to subcontract. This number consists of $4,000 in travel and $33,000 in testing costs.

Accordingly, subcontracting and ODC for ge neric a dry CEMS are estimated to be $44,500.

4.4.3 Annualized Capital Costs

Based on a three-year straight-line depreciation, annualized capital costs are estimated to be $20,077 based on the capital cost average for both wet and dry systems, as submitted by the vendors.

4.4.4 Total Annualized Costs

Total annualized costs for me rcury monitoring with a CEMS are estimated at $84,142.

Note that this estimate may be low, in re gard to administrative, sampling and analysis cost, for the first year, because the CEM is likely to undergo extra scrutiny from

35 Current rate quoted by Spectrum Gases.37 Task 1: Cost of Mercury Measurement Techniques

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management. Also, additional vendor mainte nance calls may take place which will increase the vendor’s budget as well as require time from plant personnel.

4.5 Uncertainties

 The technology is still under development.

 Limited field experience has been collected.

 No performance standard has been defined for CEMS.

 No calibration method has been defined.

 Demonstration of oxidized Hg conversion efficiency is diffi cult without OH testing. Currently envisioned cylinder au dit would not demonstrate conversion.38 Task 1: Cost of Mercury Measurement Techniques

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5. Fuel Analysis

5.1 Background and Methods

Fuel analysis as an emissions measuremen t technique implicitly utilizes an emission

factor approach; mercury emissions are so me fraction of all the mercury inputs. Mercury in the fuel is generally considered the sole source of mercury emissions though other mercury inputs could easily be inco rporated into this approach if deemed necessary. Mercury content in the fuel and the amount of fuel burned are used to determine the mercury inputs to a unit. In the extreme or maximum emissions case, mercury emissions from a unit could be es timated as the total measured mercury inputs, discounting mercury retained in re siduals such as fly ash or gypsum. An alternate approach is to apply an emission factor, either based on unit specific emission measurements or some classification average emission measurements, to the measured mercury inputs.

Measuring mercury content in the fuel and fuel inputs to units appears to be an integral part of proposed mercury control legislat ion. Mercury inputs provide the baseline which emissions are compared to in control-based legislation. Similarly, the proposed Clear Skies Act of 2003 reverts, should the administrator not establish the emissions trading system, to a control-based merc ury emissions requirement based on fuel mercury content 36

.

5.1.1 Scope and Applicability

Fuel analysis will determine the total amount of mercury in the fuel. Mercury in the fuel can be expressed on either a mass basis, either wet or dry, or can be normalized to the heating value of the fuel and be expressed on an energy basis. When the fuel is burned, the mercury in the fuel will be co nverted to elemental, oxidized, and particlebound mercury. Though the fuel analysis is mo st directly relate d to total mercury emissions, it may be possible to estimate the partitioning of the mercury based on other fuel components and fuel firing conditions.

36 “Clear Skies Act of 2003” accessed at ht tp://www.epa.gov/air/ clearskies/Air_005.pdf39 Task 1: Cost of Mercury Measurement Techniques

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5.1.2 Accuracy and Precision

Accuracy and Precision for mercury fuel anal ysis appear to be dependent upon both the analytical method and the specific ma trix being analyzed. ASTM D-3684-01 is reported to have a bias with respect to three reference materials analyzed, as

summarized in Table 5-1. Bias was significant at a 95 percent confidence level for all three reference materials but appears to be dependent on the specific matrix. The mean Hg content from ICR phase II for bituminous coals at electric utilities was 0.11 ppm 37

. This was quite comparable to the Certified Reference Material (CRM) used to evaluate bias in the ASTM method. Repeatability of the method is reported as 0.036 ppm, while reproducibility of the method is reported as 0.054 ppm. 38

Table 5-1. ASTM D-3684-01 Bias 39

CRM Description CRM value, ppm Bias, ppm

SRM 1630a Bituminous Coal, PA 40 0.0938 0.0081
SRM 2692b Bituminous Coal, WV 41 0.1333 -0.0087
SARM 20 Subbituminous to Bituminous Coal,
South Africa 42 0.25 -0.06

37 National Risk Management Research Laboratory, “CONTROL OF MERCURY EMISSIONS
FROM COAL-FIRED ELECTRIC UTILITY BOILERS: INTERIM REPORT INCLUDING ERRATA DATED 3-21-02,” EPA-600/R-01-109, April 2002.

38 D3684-01 Standard Test Method for Total Mercury in coal by the Oxygen Bomb Combustion/Atomic Absorption Method, ASTM International, West Conshohoken Pennsylvania

39 D3684-01 Standard Test Method for Total Mercury in coal by the Oxygen Bomb Combustion/Atomic Absorption Method, ASTM International, West Conshohoken Pennsylvania

40 http://patapsco.nist.gov/srmcatalog/certificates/view_cert2gif.cfm?certificate=1630a

41 http://patapsco.nist.gov/srmtcatalog/certificates/2692b.pdf40 Task 1: Cost of Mercury Measurement Techniques

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5.2 Assumptions

For this cost estimate, the fuel Hg sample is assumed to be derived from fuel samples already being collected and shipped for analysis. The equipment and techniques required to take the sample are therefore assu med to be established for each unit. It is

assumed that fuel analysis will be contracted.

The form of any regulation is expected to specify the sampling and analysis frequency. Under ICR phase II, over 152,400 shipments were recorded and over 39,500 analyses performed 43 . One thousand one hundred and forty (1,140) coal-fired units were identified at approxi mately 450 facilities 44 . Assuming a similar frequency for potential regulation will result in approximately 35 analyses per unit per year. Assuming an unbiased measurement technique and 15% RS D with respect to mercury inputs, 35 analyses should provide an annual estimate within 5.2% of actual mercury inputs with 95% confidence.

There are several ASTM me thods available for measuring mercury including D3684- 01, D6414-01, and D6722-01. Without furthe r regulatory guidance, ASTM D-3684 is
assumed to be the utilities me thod of choice and will be us ed in this cost estimate. ASTM D-3684 appears to have been widely, though not uniformly, chosen for fuel analysis in the ICR.

Costs for emission factor development, if implemented, are assumed to be on a unit
basis. The emission factor is assumed to validate the percentage of mercury inputs emitted from the stack. The emission factor could similarly be required to demonstrate no significant bias in the mercury anal ysis technique. While procedures for implementing such a validation have yet to be developed, this cost estimate will include quarterly (4) OH sampling events with three tests per sampling event. No

42 http://energy.er.usgs.gov/products/papers/B1823/append.htm

43 U.S. EPA, “ICR Data Analysis Presentation for NWF; September 8, 2000,” http://www.epa.gov/ttn/atw/com bust/utiltox/nwf_9_8.pdf

44 ibid.41 Task 1: Cost of Mercury Measurement Techniques

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additional coal samples and analysis are assu med to be associated with the emission
factor validation.

5.3 Annual Costs

5.3.1 Labor Costs

Costs for administering the fuel analysis program for Hg are de rived using estimates from the ICR supporting statement. 45 Though not specified in the ICR Supporting Statement, two technical hours per year have been included to support contracting for additional analysis. Thirty-two technical hours, 8 hours per quarter, are assumed for compiling and reviewing analytical data. Four technical hours are estimated for quarterly submission of analytical results. Routine operations are therefore expected to require 38 technical hours per year. Labor co sts for routine operation of a mercury sampling program are estimated at $2,016, including management and clerical costs.

If an emission factor verification were incl uded, additional costs would be associated with administering this program. The program is assumed to consist of four (4) OH sampling events with three (3) tests per sa mpling event. The following technical hours
have been assumed on an annual basis for verification testing:

 For obtaining an OH sampling cont ract, 40 technical hours.

 For oversight of 12 tests, 96 technical hours.

45 U.S. EPA, “Standard Form 83-1 Supporting Statement for OMB Review of ICR No._____:[ sic ] Information Collection Request for El ectric Utility Steam Generating Unit Mercury Emissions Information Collection Effort,” November 16, 1998. available at http://www.epa.gov/ttn/atw/com bust/utiltox/ 114_ss19.pdf42 Task 1: Cost of Mercury Measurement Techniques

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 To compile and review analytical data, 32 technical hours.

 To submit test results, 4 technical hours.

Total technical hours for administration of th e emission factor verification program are

therefore expected to be 172 per year. In cluding management and clerical hours labor costs for the emission factor verification pr ogram at the stack level are estimated at $9,126 annually.

5.3.2 Subcontract and ODC

Cost of mercury analysis is estimated at $54 per occurrence, which is the average of vendor indicated analysis costs of $50 46 and $58 47 . Shipping to the contract laboratory is expected to be covered by current anal ytical requirements. A total of 35 mercury analysis per year results in a mercury an alysis cost of $1,890 per year per unit.

As mentioned in section 1.1.1, costs for c ontracting for OH sampling and analysis are estimated a $15,000 per sampling event with three tests each. An emission factor verification program consisting of four (4) sa mpling events is, thus, estimated to cost $60,000 per year for each unit.

5.3.3 Total Annualized Costs

Annual costs for the mercury analysis progr am are estimated to be $3,906 with no
emission factor verifica tion program. Cost of an emission factor verification program is estimated to be $69,126. Whether an emissi on factor verification program would be required for all units or just for those wishing to demonstrate a level of mercury control would have to be defined by regulation. A nnual cost for the mercury analysis program with an emission factor verification pr ogram is estimated at $72,926 per unit.

46 Personal communication from Kim Risi, PSC Analytical Services to Carl Singer, ARCADIS on March 24, 2003.

47 Personal communication from Ken Munger, SGS Commercial Testing and Engineering, to Carl Singer, ARCADIS, on March 12, 2003.43 Task 1: Cost of Mercury Measurement Techniques

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5.4 Uncertainties

Use of Hg fuel analysis for quantifying merc ury emissions is conf ounded by the matrix specific bias associated with the analytical technique. Reducing this bias or quantifying the matrix effects may greatly influence the need to perform emission factor

verification testing. It may al so be necessary to estimate bi as associated with non-coal fuels such as pet-coke, RDF or biomass with respect to the chosen analytical technique. Additionally, QA necessary for defensible analysis at the desired detection levels must
be established.

The cost of Hg fuel analysis for quantif ying Hg emissions coul d be significantly
reduced if a reliable emission factor were developed for important equipment and fuel classes. This approach may be particularly applicable to units expecting little or no Hg control. Units burning sub-bituminous or ligni te coals controlled only by ESPs appear
to exhibit limited control. 48 On the other hand, use of a single emission factor for a unit may not be appropriate in al l cases, especially for units which change fuel or fuel blends, because the emission factor may change significantly dependent on the fuel due to changes in Hg partitioning between el emental, oxidized, and particle-bound forms.

The use of fuel analysis for quantifying Hg emissions may not be appropriate for all units or within and market based trading sc enario. The Hg emissions can be influenced by a number of factors, which may vary due to plant operating conditions and may not be representatively captured during verifi cation tests. These parameters may include fuel sources, combustion conditions, and control device operations.

48 EPA-600/R-01-10944 Task 1: Cost of Mercury Measurement Techniques

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6. Discussion and Summary

6.1 Comparison Carl: please update this section with revised costs.

Table 6-1 includes an overview of the estimated annual costs associated with the four

methods that have been reviewed. The costs for OH analysis for annual emissions estimation is $203,134. The cost for carbon trap analysis for annual Hg emissions estimation is$115,009 .The cost for CEMS and fuel analysis for annual Hg emissions estimation are $85,164 and $73,032, respectivel y. A large portion of the monitoring
costs are associated with validating the proposed measur ement against a reference method. In this case, the reference method , OH, samples represen tatively across the stack as opposed to point sampling used for Carbon Traps and CEMS or inlet Hg based fuel analysis..

Table 6-1. Summary of Mercury Annual Analysis Costs
OH Method Carbon Trap CEMS Fuel Analysis

Labor
Routine Operations, Technical Hours 436 772 255 38

Verification Testing, Technical Hours n/a 137 133 172

Total Technical Hours 436 909 388 210
Technical Labor, $ 20,710 43,178 18,430 9,975 Management Labor, $ 1,248 2,603 1,111 601
Clerical Labor, $ 1,175 2,451 1,046 566
Total Labor, $ 23,134 48,232 20,587 11,142

Subcontract & ODC
Verification Testing 180,000 39,400 37,000 60,000
Other Analysis n/a 21,640 n/a 1,890
Audit Cylinder n/a n/a 5,000 n/a

Parts & Consumables n/a n/a 2,500 n/a
Total Subcontract & ODC, $ 180,000 61,040 44,500 61,890

Annualized Capital Cost45 Task 1: Cost of Mercury Measurement Techniques

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Annualized Capital Cost, $ 0 5737 20,077 n/a

Total Annual Costs, $ 203,134 115,009 85,164 73,032

6.2 Barriers to Cost Analysis

The accuracy of cost estimates is limite d by the developing nature of the mercury emission monitoring industry. The accuracy a nd precision of the measurement methods are improving but are largely unquantified. The requirements of mercury monitoring are similarly undefined by regulation. Th e validation requirements must also be developed to satisfy the accuracy and prec ision requirements defined by regulation. Finally, the market for these validations will mature dependent on the requirements of the mercury emission monitoring industry.

The accuracy and precision of OH testing, carbon trap testing, a nd CEMS are currently undergoing evaluation under several coal-fired plant configurations. While OH testing is widely used as the reference method , the precision of the method is poorly established confounding comparisons to altern ative methods. Altern atively, generally accepted independent standards by which to judge accuracy and precision are not available; an elemental mercury gas standard is under development but an oxidized or total mercury gas standard is unavailable.

Mercury emissions from coal-fired boilers are not currently regulated under federal authority. The measurement and reporting re quirements of any proposed regulation, including incentives and penalties, will shape the type and frequency of mercury measurements. The marketplace will either develop based on industry perception of risk and reward or based on regulato ry command and cont rol requirements. Information on the reliability, O&M costs, and other metrics of various monitoring techniques are largely unavailable, though they are being evaluated by EPA during short-term testing at co al-fired power plants.

Validation of the mercury monitoring can have a large impact on the total costs of a mercury monitoring approach. Validation wi ll depend on the regulatory framework required for mercury monitoring. Our esti mates assumed validation techniques to provide results nominally equivalent to a RATA.46 Task 1: Cost of Mercury Measurement Techniques

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Finally, the cost of validation of mercury monitoring will likely change as the market for these services develop. These costs are currently based on OH testing at an
individual stack in the current market. The volume of contra cting required may significantly affect costs as the amount of travel and number of deployments are reduced. The number and location of samp ling firms providing this service will be

affected by the amount of contracting that develops. Competitive pressures are also likely to drive down costs.

6.3 Suggestions for Improvements and Additional Research

The accuracy and precision of the OH tests need to be quantified in order to establish appropriate validation procedur es with this method. This precision may define the number of tests required to achieve desired accuracy. It is particularly important to understand the precision at lo w levels of mercury where analytical variability may become a large fraction of the total vari ability. Improvements to the accuracy and precision, especially at lo w mercury levels, should be incorporated into the method prior to the evaluation of precision. A samp ling program to evaluate the precision and accuracy of the OH method is therefore recommended to evaluate low, medium, and high concentration sources.

A more accurate estimate of annual monitoring costs will require additional information regarding conti nuous application of each method. While short-term
evaluations of CEMS and a version of carbon traps are ongoing or planned, these evaluations are not likely to extend for a y ear, the benchmark typically encountered in Part 75. Quantitative information regardi ng operation and maintenance and reliability will be necessary for method comparis on. Preferably, thes e evaluations should encompass a wide range of coals and plant configurations.End of Document