Mercury Emissions Monitoring Under CAMR

1. Mercury Emissions Monitoring Under CAMR Reynaldo (Rey) Forte Clean Air Markets Division, U.S. EPA 2007 SOUTHEASTERN PERMITTING WORKSHOP Tampa, FL May 9-11, 2007

2. Background • The Clean Air Mercury Rule (CAMR) requires sources to install and certify mercury monitoring systems by January 1, 2009 • Affected sources have begun ordering monitoring and data acquisition systems • Vendors have expressed a high level of confidence that continuous mercury emission monitoring systems will be available to meet industry needs and CAMR requirements

3. Background • Development of the CAMR monitoring program has been a collaborative effort between EPA (OAQPS, ORD, CAMD), NIST and industry (EPRI, RMB, WRI, EERC and others) • EPA continues its full commitment to working with utilities, vendors, academia, NIST, and other organizations to successfully develop all aspects of the CAMR mercury monitoring program • Most major technical issues are behind us but some challenges remain

4. Mercury Monitoring - Next Steps • Test and promulgate instrumental and sorbent-based alternative mercury reference methods • Develop NIST-traceable calibration gases and protocols • Develop training materials and conduct training for EPA Regions, States and sources • Order, install and certify monitors - sources • Collect, quality assure, and report data – sources • Receive, quality assure, and audit data - EPA

5. Evaluation and Validation of Alternative Reference Methods • EPA and industry (EPRI and others) are completing remaining field validation tests for instrumental and sorbent trap-based reference methods that provide alternatives to the lengthy and complex Ontario Hydro reference method • An instrumental reference method (IRM) that provides timely RATAs with immediate, real-time results is easier to implement than OH, and is consistent with NOX and SO2 trading programs • A sorbent trap reference method is considered another viable alternative method. When it combines thermal desorption/direct combustion techniques, it allows for onsite analysis • EPA and EPRI are currently completing sorbent trap method comparison studies using a modified EPA Method 301 which compares existing data from sorbent trap systems against data from the Ontario Hydro reference method

6. Availability of Alternative Reference Methods EPA is preparing a rule package for both the instrumental and sorbent-based reference methods • Process being expedited through direct final rule making effort • Final rule tentatively scheduled for May publication in the Federal Register • Would become final in early July if no adverse comments are received

7. Proposed Monitoring Changes to Part 75 • Proposed Part 75 rule changes published August 22, comment period closed in October 06 • Reference Method 29 proposed as an alternative Ontario Hydro reference method • Minor technical/procedural changes proposed to Subpart I of Part 75 including adding multiple/common stack heat input procedures • Solicited comments relating to the development of reference method based on sorbent trap technology • Received comments were not extensive - essentially supportive of changes • Rule expected to become final this summer

8. NIST-Traceable Hg Calibration Standards • EPA and NIST continue their collaborative work to provide NIST traceability for elemental and oxidized mercury calibration standards • We are expecting to have NIST-traceable gas protocols in 2007 for use in certifying CEMS and sorbent trap monitoring systems

9. Mercury Compliance Monitoring Options and Requirements Continuous Emissions Monitoring Systems (CEMS) Sorbent Traps – Appendix K Low Mass Emissions (LME) Monitoring Methodology

10. CEMS Initial Certification • 7-day calibration error test • Linearity Check (elemental Hg) • 3-level System Integrity Check (oxidized Hg) - monitors with Hg converter only • Cycle Time Test • Relative Accuracy Test Audit (RATA) • Bias Test

11. CEMS On-going Quality Assurance • Daily calibration error test (elemental or oxidized Hg) • Weekly 1-level System Integrity • Quarterly Linearity Check (elemental Hg) or3-level System Integrity Check (oxidized Hg) • Annual RATA (no semi-annual threshold • Bias Test

12. Appendix K – Sorbent Trap System Basics • Appendix K – Sorbent Trap systems consist of a pair of sampling trains that collect an integrated sample over a specified collection period • Sorbent traps collect the Hg and have 3 sections. • Section 1; Main Sample Collection Section • Section 2; Breakthrough Sample Collection Section • Section 2; Spiked Section for QA • Each sampling train uses a dry gas meter to record the volume of stack gas sampled over the course of each sample collection period

13. Appendix K – Sorbent Trap Systems • Initial Certification • RATA • Bias Test • Initial 3-level Dry Gas Meter (DGM) Calibrations • Initial DGM Temperature Sensor and Calibration Check • Initial DGM Barometer Calibration Check

14. Appendix K – Sorbent Trap Systems • On-going Quality Assurance for Appendix K systems : • Annual RATA (no semi-annual threshold) • Annual Bias Test • Quarterly Dry Gas Meter (DGM) Calibrations • Quarterly DGM Temperature Sensor and Calibration Check • Quarterly DGM Barometer Calibration Check • Quality Assurance for each Appendix K sample collection period: • Pre- and Post- sample collection Leak Check • Monitor Ratio of stack gas flow to sample collection flow • Sorbent Trap Breakthrough check (section 2 of trap) • Percent Trap Agreement • Spike Recovery (section 3 of trap)

15. Substitute Data for CEMS andAppendix K • In August 2006, EPA proposed to consolidate the Substitute Data requirements for CEMS and Appendix K. • This decision allows for the use of an Appendix K system as a back-up to CEMS in a way that does not complicate the Substitute Data requirements for when neither system is available.

16. Hg-LME Monitoring Methodology Rather than install Hg analyzers or sorbent traps, affected units with lower potential levels of Hg (≤ 29 lbs/yr potential emissions) may qualify for a Low Mass Emissions (LME) monitoring methodology (Part 75.81)

17. Low Mass Emissions (LME) Units • Low Hg emitting units (≤ 29 lbs/yr potential emissions) may qualify for the LME methodology • This methodology requires an initial and on-going emission testing • Maximum potential stack flow rate from initial test is used to demonstrate that the unit’s potential to emit is not greater than the 29 lb threshold. • The Hg concentration from the test is then used with actual stack flow data to determine hourly emissions • Ongoing re-testing is required annually if the calculated potential Hg emissions are ≤ 9 lb/yr, and semiannually if the potential emissions are between 9 and 29 lb/yr (NO GRACE PERIODS!) • Actual reported Hg mass is used for ongoing qualification testing.