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Department of the Environment A History of Power Plant Controls in Maryland What Did We Learn? – Where do We go Next? Part 3 – SO2 Issues.

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Presentation on theme: "Department of the Environment A History of Power Plant Controls in Maryland What Did We Learn? – Where do We go Next? Part 3 – SO2 Issues."— Presentation transcript:

1 Department of the Environment A History of Power Plant Controls in Maryland What 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 Acts 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 weve seen a dramatic drop in how often Maryland coal plants are called upon to generate energy

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

7 Brandon Shores Unit 1 Brandon Shores Unit 2 Crane Unit 1 Crane Unit 2 Wagner Unit 2 Wagner Unit 3 Total 2012 Annual SO2 Tons 1,5471,3011, ,5134,96012, Annual SO2 Limit, Tons 7,0417,3472,0002,1491,6183,25223, On Annual SO2 Limit, Tons 5,3925,6271,5321,6461,2392,49017,926 HAA set annual and ozone season caps and allowed system-wide averaging With tougher ozone standard and focus on peak days – units that under-controlled are now being re-evaluated Raven System Wide Compliance with MD HAA Units with red font use credits from units in black font to meet annual HAA Limit This numbers shows Annual tons well below annual limits

8 Raven Power – Brandon Shores Unit Capacity (MW) SOx Controls Brandon 1 (Coal) 700FGD Brandon 2 (Coal) 700FGD 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 – Capacity Factors Brandon Shores 1Brandon Shores 2

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 Unit Capacity (MW) SOx Controls Wagner 2 (Coal) 136None Wagner 3 (Coal) 359None Wagner Power Station Built in 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 – Capacity Factors Wagner 2Wagner 3

14 Can see considerable variability in rates resulting from load and coal sulfur content Wagner - Unit 2 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 SO2 rates 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 Unit Capacity (MW) SOx Controls CP Crane 1 (Coal)200PRB Coal CP Crane 2 (Coal)200PRB Coal 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 Clearly can see that lower rates can be achieved with low sulfur coal and careful attention to coal blending activities Can also see that there are routine emission spikes. Controlling these spikes is critical for complying with a 1- hour standard MDE Current Thinking: Allowable rate of 700 to 800 lb/hr

19 Coal Fired UnitsOld SO2 Limit (as lb/hr)Proposed SO2 Limits (1 hr avg) Brandon Unit 1 (Scrubber) 1.2 lbs/mmBtu (~ 9,600 lbs/hr) 300 to 500 lb/hr SO2 Brandon Unit 2 (Scrubber) 1.2 lbs/mmBtu (~ 9,600 lbs/hr) 300 to 500 lb/hr SO2 Wagner Unit 2 (None) 1 wt% Sulfur Coal (~3,355 lbs/hr) 500 to 1000 lb/hr SO2 Wagner Unit 3 (None) 1 wt% Sulfur Coal (~4,567 lbs/hr) 500 to 1000 lb/hr SO2 Crane Unit 1 (Use of PRB Coal) 3.5 lbs/mmBtu (24-hr Average) (~ 8,750 lbs/hr) 700 to 800 lb/hr SO2 Crane Unit 2 (Use of PRB Coal) 3.5 lbs/mmBtu (24-hr Average) (~ 8,750 lbs/hr) 700 to 800 lb/hr SO2 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 MDEs 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 - Units 1 and 2 Dickerson – Units 1, 2 and 3 Chalk Point – Units 1 and 2 MorgantownChalk PointDickerson

22 Morgantown Unit 1 Morgantown Unit 2 Chalk Pt Unit 1 Chalk Pt Unit 2 Dickerson Unit 1 Dickerson Unit 2 Dickerson Unit 3 Total 2012 Annual SO2 Tons 1,2311,6982,4702, , Annual SO2 Limit, Tons 6,1086,0663,4033,5681,6161,7701,67824, On Annual SO2 Limit, Tons 4,6784,6462,6062,7331,2381,3551,38518,641 HAA set annual and ozone season caps and allowed system-wide averaging NRG 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. NRG System Wide Compliance with MD HAA This numbers shows annual tons well below annual limits Each unit, individually, was well under the unit-specific HAA cap for that unit

23 Unit Capacity (MW) SO2 Controls Morgantown 1 (coal) 640FGD Morgantown 2 (coal) 640FGD 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 – Capacity Factors Morgantown 1Morgantown 2

25 Morgantown – Unit 1 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 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

26 Morgantown – Unit 2 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 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

27 Unit Capacity (MW) SO2 Controls Both Units 1 & 2 vent through a common FGD and a common 400 ft stack 710FGD 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 Very low rates consistent with FGD control efficiency Much higher rates during bypass stack operations 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 Unit Capacity (MW) SO2 Controls All three Units 1, 2 & 3 vent through a common FGD and a common 400 ft stack 570FGD

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 Very low rates consistent with FGD control efficiency Much higher rates during bypass stack operations MDE Current Thinking: Allowable FGD rate of 700 to 1000 lb/hr

33 Coal Fired UnitsOld SO 2 Limit (as lb/hr) Proposed SO2 Limits (1 hr Avg) Chalk Point Unit 1&2 (Scrubber, Common Stack) 1% Sulfur Coal (~ 10,433 lbs/hr) 700 to 1000 lb/hr Morgantown Unit 1 (Scrubber) 3.5 lbs/mmBtu (~ 22,628 lbs/hr) 700 to 800 lb/hr Morgantown Unit 2 (Scrubber) 3.5 lbs/mmBtu (~ 22,628 lbs/hr) 700 to 800 lb/hr Dickerson Unit 1, 2, & 3 (Scrubber, Common Stack) 2.8 lbs/mmBtu (~ 13,826 lbs/hr)700 to 1000 lb/hr Short-Term SO2 Limits NRG– Current MDE Thinking

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 MDEs 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 SO2 control strategy Total capacity = 205 MW coal Unit Capacity (MW) SO2 Controls Fluidized Bed Boiler 180Fluidized bed

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

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 EPAs draft guidance Suggest that early December or January 2014 meeting focus solely on short-term SO2 limits


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