Mercury Monitoring Under CAMR

1. Mercury Monitoring Under CAMR Ruben Deza, Ph.D. Clean Air Markets Division U.S. Environmental Protection Agency

2. Two Alternative Monitoring Systems • Continuous Emissions Monitoring System • Similar to current systems in the Acid Rain & NOx budget programs • Measures “real-time” vapor phase Hg concentration in the stack

3. Two Alternative Monitoring Systems • Sorbent Traps • Continuously samples the stack gas---collects vapor phase Hg on sorbent media (e.g., activated carbon) • Accumulation of Hg over an extended period of time, e.g., a few days or weeks • Lab analysis of the tubes at end of period • Other approaches, including on-site analysis under development

4. Two Alternative Monitoring Systems (cont.) • EPA’s Assessment • Both types of systems have been demonstrated to be capable of accurately measuring Hg emissions • We believe that consistent, reliable Hg measurements will be achievable by the rule implementation date (2009) • The sorbent trap system represents a departure from traditional monitoring approaches in cap-and-trade programs (i.e., CEMS) • Initially, skeptical about ability of sorbent traps to provide high quality data • Technical improvements to the system and recent data from lab tests and field demonstrations changed this perception • New QC enhances assurance about the quality of the data obtained with sorbent traps - Appendix K provides most of the QC procedures

5. Mercury CEMs

6. Sorbent Trap

7. Technology Demonstrations • To provide an opportunity to test equipment and address problems such as: • Measurement of very low Hg concentrations • Interferences (SO2, SO3 Cl2, NOx, HCl) • Biases (sample transport/reactivity of oxidized forms, conversion efficiency) • Instrument reliability • Past Demos: CEMS and sorbent traps were tested in three power plants • Bituminous and sub-bituminous coals, with and without NOx, SO2 or PM controls • Initially, large number of equipment failures and problems with test procedures • Higher degree of success towards the end • Current Demos: two ongoing demonstration projects • CEMS and sorbent traps are being tested in accordance with Part 75 requirements • CEMS and sorbent traps performing well • Instrumental reference method provisions are also being tested • Strong support from industry

8. Mercury Monitoring, The Basics • All units would have the flexibility to install sorbent traps or CEMS • Some low- emitting units (< 29 lbs/yr) sources may qualify for a third option • This two-tiered approach requires annual stack testing if Hg emissions are< 9 lb/yr and semiannual testing if emissions are greater than 9 lb/yr, but < 29 lb/yr • Sources may also petition to use an alternative monitoring system, under Subpart E of Part 75

10. Mercury Monitoring Under CAMR (The Basics)--- cont’d • Required continuous monitoring for CAMR units: • Hg concentration • Stack gas flow rate • Moisture---if needed • Diluent gas (CO2 or O2)---if needed for heat input • Monitor certification deadlines • For existing units--- January 1, 2009 • For new units---90 operating days or 180 calendar days after commencement of commercial operation

11. Mercury Monitoring Under CAMR (The Basics)---cont’d • Sources are required to submit electronic quarterly reports, beginning on 1/1/09, containing: • Facility information; • Hourly and cumulative Hg mass emissions • Hourly and cumulative heat input (if applicable) • Results of required QA tests • CAMR units that are also subject to the Acid Rain or NOx Budget Program must continue to meet those monitoring and reportingrequirements

12. Additional Information The next slides provide additional information for those interested in more details

13. Mercury Monitoring Language in the CAMR Regulation • The blueprint for the Hg trading program is found in Subpart HHHH of 40 CFR Part 60. • Subpart HHHH includes monitoring provisions (§§60.4170-76) • Subpart I has been added to Part 75 • Establishes monitoring methods for Hg mass emissions • Similar to Subpart H for the NOx SIP Call • Revisions have been made to key sections of Parts 72 and 75 to facilitate implementation of the Subpart I monitoring provisions

14. Mercury Monitoring Language in the CAMR Regulation (cont’d) • NSPS Subpart Da has been revised. • New Subpart Da electric generating units constructed after 1/30/04 must meet an output-based Hg emission limit • Compliance with the NSPS is determined on a 12-month rolling average basis, using data from a CEMS or sorbent trap monitoring system • The NSPS is needed to justify the Hg trading program for existing units under § 111(d) of the Clean Air Act • Performance Specification 12-A (certification procedure for the Hg CEMS required under Subpart Da) has also been promulgated as part of the CAMR rule package

15. Certification Test Requirements for Hg Monitoring Systems • For Hg CEMS: • 7-day calibration error test---with elemental Hg or HgCl2 • System integrity check at 3-levels, with HgCl2, if the CEMS has a converter • Linearity check with elemental Hg • Cycle time test • RATA and bias test • For Sorbent Traps Systems: • RATA and bias test • Applicable QA/QC procedures in Appendix K must be implemented

16. On-Going Quality-Assurance Requirements for Hg Monitors • For Hg CEMS: • Daily calibrations---with elemental Hg or HgCl2 • Weekly system integrity check, if the CEMS has a converter (not required if HgCl2 is used for daily calibrations) • Quarterly linearity check with elemental Hg or system integrity check with HgCl2 • Annual RATA and bias test • For Sorbent Traps Systems: • Annual RATA and bias test • QA/QC procedures in Appendix K must be implemented

17. Hg Missing Data Procedures • For CEMS • Modeled after the SO2 missing data routines • The percent monitor data availability (PMA) “trigger” points are slightly lower for Hg than for SO2 (e.g., for Hg, report the MPC if the PMA is < 70%, instead of 80%) • For Sorbent Trap Systems • Missing data occurs when gas sample is not extracted from the stack or the results for the pair system traps are missing or invalid • The missing data routines include data availability “trigger points” and lookback procedures similar to those prescribed for Hg CEMS

18. Recordkeeping and Reporting • Sources are required to submit electronically: • A monitoring plan to monitor Hg emissions in addition to the AR and State of Federal NOx requirements and report emissions quarterly • Quarterly reports including facility information, hourly Hg mass emissions, heat input, if applicable; missing data periods and QA reports including RATAs, calibration tests, etc

19. Recordkeeping and Reporting (cont.) • Each source must have a Hg Authorized Account Representative responsible for submission of permit applications, monitoring plans and certification applications, holding and transferring of Hg allowances, and submission of emissions data and compliance certification reports • The allowance tracking system will be consistent with tracking systems developed for the NOX SIP Call and Acid Rain Program. • Transfers can occur between any accounts at any time of year except during EPA’s reconciliation process

20. Tests used for QA/QC and Reference Method • For CEMS: • Linearity Check – With elemental Hg • 7-day calibration • RATA on a µg/scm basis • System integrity check at 3 levels if the CEMS has a converter • For Sorbent Traps: • RATA on a µg/scm basis • Bias test • Appendix K provides most of the QC procedures • Reference Method: ASTM D6784-02 also known as Ontario Hydro • An instrumental Reference method under development