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A History of Power Plant Controls in Maryland What Did We Learn? – Where do We go Next?

A History of Power Plant Controls in Maryland What Did We Learn? – Where do We go Next?. Part 3 – SO2 Issues. Healthy Air Act SO2 Caps. Healthy Air Act caps reduced annual SO2 emissions. Issues With SO2 Emissions.

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A History of Power Plant Controls in Maryland What Did We Learn? – Where do We go Next?

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  1. A History of Power Plant Controlsin MarylandWhat Did We Learn? – Where do We go Next? Part 3 – SO2 Issues

  2. Healthy Air Act SO2 Caps Healthy Air Act caps reduced annual SO2 emissions

  3. Issues With SO2 Emissions • The Healthy Air Act’s annual caps – and company-wide averaging concepts - worked extremely well to cost-effectively reduce annual SO2 emissions • These reductions have helped Maryland come into attainment for the fine particulate standard and meet the Regional Haze requirements of the Clean Air Act • The new 1-hour SO2 standard demands an entirely different regulatory scheme • 1-hour emission limits instead of an annual cap • Unit-by-unit controls instead of company-wide averaging • Units that under-controlled as part of a company-wide averaging plan are struggling to meet the limits needed because of the new standard • Short-term periods where the scrubbers are not being used (for example during boiler emergencies and CEM QA) are also a problem

  4. Very Old Short-Term Emission Limits • The HAA used annual caps to drive very significant annual emission reductions • The short-term limits for SO2 in Maryland regulations date back to the 1990s • They are clearly not appropriate for the new 1-hour SO2 standard • All short-term limits for all units will need to be updated

  5. Capacity Factor Trends Over the past 5 years we’ve seen a dramatic drop in how often Maryland coal plants are called upon to generate energy

  6. Raven Power Wagner Power Station • Brandon Shores - Units 1 and 2 • Wagner – Units 1, 2, 3 and 4 • C.P. Crane – Units 1 and 2

  7. Raven System Wide Compliance with MD HAA HAA set annual and ozone season caps and allowed “system-wide” averagingWith tougher ozone standard and focus on “peak days” – unitsthat “under-controlled” are now being re-evaluated This numbers shows Annual tons well below annual limits Units with red font use credits from units in black font to meet annual HAA Limit

  8. Raven Power – Brandon Shores • Built in 1984 • Boiler type • Units 1 & 2 are both walled fired coal units manufactured by Babcock & Wilcox • Installed two scrubbers (Fluidized Gas Desulfurization/FGD) in 2010 (about $875 million) • Total capacity = 1,400 MW

  9. Brandon Shores 1 Brandon Shores 2 Brandon Shores – Capacity Factors

  10. Brandon Shores - Unit 1 Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable rate of 300 to 500 lb/hr

  11. Brandon Shores - Unit 2 Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable rate of 300 to 500 lb/hr

  12. Wagner Power Station • Built in 1959 - 1972 • Boiler types • Units 2 & 3 are both wall fired coal units manufactured by Babcock & Wilcox • Units 1 & 4 are both gas and oil wall fired units manufactured by Babcock & Wilcox • No add-on control technology. Coal fired units at times have used lower sulfur coal as a control strategy • Total Coal capacity = 495 MW

  13. Wagner 2 Wagner 3 Wagner – Capacity Factors

  14. Wagner - Unit 2 Can see considerable variability in rates resulting from load and coal sulfur content MDE Current Thinking: Allowable rate of 500 to 1000 lb/hr

  15. Wagner – Unit 3 Lack of emission controls and the use of coal with higher sulfur content result in the highest SO2rates in Maryland and some of the highest in the eastern United States MDE Current Thinking: Lower end of current emissions still too high. Allowable rate appears to be in the 500 to 1000 lb/hr range

  16. C.P. Crane • Built in 1963 • Boiler types • Units 1 & 2 are both coal fired cyclone units manufactured by Babcock and Wilcox • No add-on control technology. Uses Powder River Basin (PRB) low sulfur coal as a control strategy • Total capacity = 400 MW

  17. Capacity Factors at Crane • Dramatic reductions since 2001 to 2007 timeframe • Units are simply not being called upon to run as much as they used to be called upon

  18. Crane - Units 1 & 2 Can also see that there are routine emission spikes. Controlling these spikes is critical for complying with a 1-hour standard Clearly can see that lower rates can be achieved with low sulfur coal and careful attention to coal blending activities MDE Current Thinking: Allowable rate of 700 to 800 lb/hr

  19. Raven Power – Current MDE Thinking

  20. Preliminary SO2 Modeling - Raven • MDE and DNR have performed preliminary modeling for the coal fired units in the Raven Power system • Sierra Club has also performed modeling of the Ravens units • More refined modeling is underway • Preliminary modeling indicates that MDE’s current thinking on short-term limits for the Raven coal fired units will model attainment for the 1-hour SO2 standard

  21. NRG Energy Inc. Morgantown Dickerson Chalk Point • Morgantown - Units 1 and 2 • Dickerson – Units 1, 2 and 3 • Chalk Point – Units 1 and 2

  22. NRG System Wide Compliance with MD HAA HAA set annual and ozone season caps and allowed “system-wide” averagingNRG added scubbers at all three of their plants. Because of this The NRG units all contributed proportionally to system-wide compliance. There are no units that “under-controlled. Each unit, individually, was well under the unit-specific HAA cap for that unit This numbers shows annual tons well below annual limits

  23. NRG – Morgantown • Built in 1967 • Boiler types • Units 1 & 2 are both tangential fired coal units manufactured by Alstom • Installed two scrubbers (FGD) in 2009 for approximately $715 million • Total capacity = 1,280 MW coal

  24. Morgantown 1 Morgantown 2 Morgantown – Capacity Factors

  25. Morgantown – Unit 1 During routine operation, emissions are controlled with an FGD and vent to a shorter “FGD” stack. During upset situations, emissions vent to a much taller “bypass” stack Much higher rates during bypass stack operation Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable FGD rate of 700 to 800 lb/hr

  26. Morgantown – Unit 2 During routine operation, emissions are controlled with an FGD and vent to a shorter “FGD” stack. During upset situations, emissions vent to a much taller “bypass” stack Much higher rates during bypass stack operation Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable FGD rate of 700 to 800 lb/hr

  27. NRG – Chalk Point • Built in 1964 & 1965 • Boiler types • Units 1 & 2 are both wall fired coal units manufactured by Babcock and Wilcox • Installed scrubber (FGD) in 2009 for approximately $475 million • Total capacity = 710 MW coal

  28. Chalk Point – Capacity Factors

  29. Chalk Point Units 1 & 2 Both units vent to a common stack. During routine operation, emissions are controlled with an FGD and vent to a shorter “FGD” stack. During upset situations, emissions vent to a much taller “bypass” stack Much higher rates during bypass stack operations Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable FGD rate of 700 to 1000 lb/hr

  30. NRG - Dickerson • Built in 1957, 1957, & 1960 • Boiler types • Units 1, 2, & 3 are all tangential fired coal units manufactured by Combustion Engineering, Inc. • Installed scrubber (FGD) in 2009 for approximately $475 million • Total capacity = 573 MW coal

  31. Dickerson – Capacity Factors

  32. Dickerson – Unit 1, 2 and 3 All three units vent to a common stack. During routine operation, emissions are controlled with an FGD and vent to a shorter “FGD” stack. During upset situations, emissions vent to a much taller “bypass” stack Much higher rates during bypass stack operations Very low rates consistent with FGD control efficiency MDE Current Thinking: Allowable FGD rate of 700 to 1000 lb/hr

  33. NRG– Current MDE Thinking Short-Term SO2 Limits

  34. Preliminary SO2 Modeling - NRG • MDE and DNR are in the process of performing preliminary modeling for the coal-fired units in the NRG system • Sierra Club has also performed modeling of the NRG units • Preliminary information indicates that MDE’s current thinking on short-term limits for the NRG coal-fired units will model attainment for the 1-hour SO2 standard when the FGDs are running • MDE continues to analyze the NRG SO2 emissions that occur during bypass stack operation when emissions are vented through the taller stacks uncontrolled

  35. AES Warrior Run • Built in 1999 • Boiler type • Coal-fired atmospheric circulating fluidized bed unit, manufactured by ABB • No add-on control technology. Uses fluidized bed technology as a SO2control strategy • Total capacity = 205 MW coal

  36. AES Warrior Run MDE Current Thinking: No modeling has been completed for Warrior Run. Allowable rate being analyzed Low rates consistent with inherently clean design of fluidized bed boilers

  37. Next Steps – SO2 • Significant additional modeling is underway • Continue to analyze options for emission reductions at Crane and Wager 3 • Continue to work with EPA on the “Bypass Stack” issues at all three NRG Plants • Additional modeling of by-pass stack issues is underway • Continue to work on start-up/shut-down issues • Continue to work with EPA and other states on the form of the short-term limits needed for the new SO2 standard • Lb/hr or lb/mmBtu with a short-term average • Continue to work with stakeholders on proposed limits • Continue to work with EPA on “early action” provisions of EPA’s draft guidance • Suggest that early December or January 2014 meeting focus solely on short-term SO2 limits

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