Michael Craig Advisers: Paulina Jaramillo, Haibo Zhai , and Kelly Klima

1. Cost-Effectiveness of Flexible Carbon Capture and Sequestration for Complying with the Clean Power Plan Michael Craig Advisers: Paulina Jaramillo, HaiboZhai, and Kelly Klima USAEE Conference, Pittsburgh, PA October 26, 2015

2. Outline • Background • Clean Power Plan • Flexible Carbon Capture and Sequestration • Methods • Power system modeling • Flexible CCS modeling • Initial Results • Conclusions and Policy Implications • Future Work

3. Clean Power Plan • Limits CO2 emissions from existing fossil-fired generators (Final Rule, 1507-1542) • Less coal-fired generation, more NGCC and renewable generation • States choose compliance strategy • Type of standard (Final Rule, 882-884) • Plan type (Final Rule, 879-880) • Single vs. multi-state (Final Rule, 880-881) • 1 compliance option: carbon capture and sequestration (CCS) retrofit (Final Rule, 34857) • Little research on alternative compliance strategies with CPP (ISOMAP)

4. Normal and Flexible CCS • Continuous operation by normal CCS unit: • Reduces CO2 emissions rate • Reduces net capacity, net efficiency, and ramp rate

5. Flexible CCS differs from normal CCS by including venting and solvent storage components. • Venting: bypass CO2capture system • Solvent storage: store some rich and lean solvent in tanks • Stored solvent displaces continuously regenerated solvent • Charging: regenerate stored lean solvent • Discharging: generate electricity using stored lean solvent

6. Normal and Flexible CCS • Continuous operation by normal CCS unit: • Reduces CO2 emissions rate • Reduces net capacity, net efficiency, and ramp rate • Venting by flexible CCS unit (relative to CCS unit): • Increases CO2 emissions rate • Increases net capacity, net efficiency, and ramp rate • Discharging stored solvent by flexible CCS unit (relative to CCS unit): • Maintains post-CCS CO2 emissions rate • Increases net capacity, net efficiency, and ramp rate • Requires stored lean solvent

7. Why Flexible CCS? • May provide system-wide benefits (van der Wijk et al. 2014, Cohen et al. 2013, Cohen et al. 2012, Delarueet al. 2012, Chalmers and Gibbins 2007) • Reduce wind curtailment and reserve and dispatch costs • May be more profitable than normal CCS (Bandyopadhyay and Patiño-Echeverri2014, Oates et al. 2014, Versteeg et al. 2013, Patiño-Echeverri et al. 2012, Delarue et al. 2012, Ziaii et al. 2009) • But past papers on system benefits compare flexible CCS to normal CCS (van der Wijk et al. 2014, Cohen et al. 2013, Cohen et al. 2012) • Not more common CO2 emission reduction technologies

8. Research Motivation and Question • Little analysis of alternative compliance with CPP • No system comparisons of flexible CCS to wind, re-dispatch, and other common emissions reductions technologies • Accounting for system benefits, is flexible CCS a cost-effective compliance strategy with the CPP? • Compare to normal CCS retrofits, generation at existing NGCC, and new wind • Develop operational model of flexible CCS that can be included in a unit commitment model

9. Power System Modeling Left: MISO market area. Right: my modeled region. • Use unit commitment and economic dispatch (UCED) model in PLEXOS • Co-optimize energy and reserve markets • No transmission constraints • Build 2030 “base” CPP-compliant fleet • Add wind, normal or flexible CCS to basefleet to create alternate fleets • Study region: MISO • Lots of coal and wind resources Source: misoenergy.org Source: amcharts.com

10. Modeling CPP • Fleet dispatching effects: CO2 price (Oates et al. 2015) • 1) Set CO2 price • 2) Apply CO2 price to affected units • 2) Run economic dispatch for year (MATLAB) • 3) Compare affected unit annual emissions to CPP regional mass limit • 4) If emissions > mass limit, increase CO2 price and go back to step 2 • Include final CO2 price in dispatch and reserve costs of affected units

11. Flexible CCS Model • Develop original set of parameters, generators and constraints to model flexible CCS operations • Break 1 flexible CCS generator into multiple components in UCED • Estimate parameters via literature review and regressions with IECM data • Couple operations of units with over 35 constraints • Include flexible CCS model in UCED model • Provides better approximation of operations, costs and emissions than prior models (van der Wijk et al. 2014.)

12. Flexible CCS Model: Parameter Estimation • Two methods: • Literature review (van der Wijk et al. 2014, Oates et al. 2014, Versteeg et al. 2013, Cohen et al. 2013, Patiño-Echeverriet al. 2012, IEAGHG 2012) • IECM regressions

13. Flexible CCS Model: Generators Base Coal Plant

14. Traditionally, model CCS parasitic load internal to CCS plant. Base CCS Generator CO2 Capture System

15. I break out CCS parasitic load as separate component... Base CCS Generator CO2 Capture System

16. And add separate component for generation while venting... Venting Generator Base CCS Generator CO2 Capture System

17. And add separate components for solvent storage… Charging Dummy 1 Venting Generator Stored Solvent Pump Unit 1 Base CCS Generator Discharging Dummy 1 Discharging Dummy 2 Stored Solvent Pump Unit 2 CO2 Capture System Charging Dummy 2

18. And add a venting while charging component. Charging Dummy 1 Venting Generator Stored Solvent Pump Unit 1 Base CCS Generator Discharging Dummy 1 Discharging Dummy 2 Stored Solvent Pump Unit 2 CO2 Capture System Venting when Charging Generator Charging Dummy 2

19. Flexible CCS Model: Constraints Electricity generation Solvent flow rate Offered reserves Minimum stable load Ramping Volume of stored solvent Units on/off

20. Initial Results: Clean Power Plan Mar. 24 Jan. 1 Day of Year • CPP increases averageelectricity price butdecreases price variance • Suggests lower profitabilityof flexible CCS

21. Initial Results: Flexible CCS Model Operations Operations of 595 MW flexible CCS generator in CPP fleet.

22. Flexible CCS unit generates electricity mostly at base CCS generator, acting like a normal CCS unit. Base CCS SS Discharge Vent

23. Solvent storage discharge units mostly provide regulation up reserves. SS Discharge Base CCS Vent

24. Solvent storage discharge units also provide raise reserves. SS Discharge Base CCS & Vent

25. Pending Results: Cost-Effectiveness of Flexible CCS versus Alternative Compliance Strategies

26. Conclusions and Policy Implications • CPP’s suppression of price variability may reduce profitability of flexible CCS • Based on analysis so far, value added of flexible CCS is provision of reserves • Could yield cost savings as reserve requirements increase with wind penetration • Comparison to normal CCS retrofits, new wind, and existing NGCC fleets will inform attractiveness of flexible CCS as CPP compliance strategy

27. Future Work • Run normal CCS, flexible CCS, and new wind fleets • Compare emissions and costs • Run low and high natural gas price scenarios • Compile capital cost data • Calculate break-even flexible CCS capital cost with respect to alternative CO2 emissions reduction technologies

28. Acknowledgements Thanks to Paulina Jaramillo, HaiboZhai and Kelly Klima (CMU) Thanks to Achievement Rewards for College Scientists, the National Science Foundation (Grant Number EFRI-1441131) and The Steinbrenner Institute for financial support Thanks to Energy Exemplar for academic license

29. Thanks!Questions?

30. Citations Bandyopadhyay, R., and D. Patiño-Echeverri. (2014). Alternative energy storage for wind power: coal plants with amine-based CCS. Energy Procedia (63): 7337-7348. Chalmers, H., and J. Gibbins. (2007). Initial evaluation of the impact of post-combustion capture of carbon dioxide on supercritical pulverized coal power plant part load performance. Fuel (86): 2109-2123. Cohen, S. M., et al. (2013). Optimal CO2 capture operation in an advanced electric grid. Energy Procedia (37): 2585–2594. Cohen, S.M., et al. (2012). Optimizing post-combustion CO2 capture in response to volatile electricity prices. Intl. J. of Greenhouse Gas Control (8): 180-195. Delarue, E., P. Martens and W. D’haeseleer. (2012). Market opportunities for power plants with post-combustion carbon capture. Intl. J. of Greenhouse Gas Control (6): 12-20. IEAGHG. (2012). Operating Flexibility of Power Plants with CCS. Fischbeck, P., H. Zhai, and J. Anderson. (2015). ISOMAP: A techno-economic decision support tool for guiding states’ responses to the EPA Clean Power Plan. Available at http://www.cmu.edu/energy/cleanpowerplantool/ Oates, D.L., and P. Jaramillo. (2015). State cooperation under the EPA’s proposed Clean Power Plan. Electricity Journal (28): 1-15. Oates, D. L., et al. (2014). Profitability of CCS with flue gas bypass and solvent storage. International Journal of Greenhouse Gas Control (27): 279–288. Patiño-Echeverri, D., et al. (2012). Reducing the energy penalty costs of postcombustion CCS systems with amine-storage. Environmental Science and Technology (46): 1243–1252. U.S. Environmental Protection Agency. “Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units; Final Rule.” [Pre-publication.] Aug. 2015. U.S. Environmental Protection Agency. Regulatory Impact Analysis for the Clean Power Plan Final Rule. Aug. 2015. Van der Wijk, P.C., et al. (2014). Benefits of coal-fired power generation with flexible CCS in a future northwest European power system with large scale wind power. International Journal of Greenhouse Gas Control (28): 216-233. Versteeg, P., et al. (2013). Cycling coal and natural gas-fired power plants with CCS. Energy Procedia (37): 2676-2683. Ziaii, S., et al. (2009). Dynamic operation of amine scrubbing in response to electricity demand and pricing. Energy Procedia (1): 4047-4053.

31. Supporting Slides

32. How do CCS and flexibleCCS retrofits affect powerplant characteristics?

33. Coal-fired generatorcharacteristics pre-CCSretrofit.

34. Retrofitting CCS reducesCO2 emissions but also reduces net capacity,net heat rate, and ramp rate.

35. Flexible CCS venting eliminates CCS parasiticload and increasesCO2 emissions.

36. Flexible CCS solvent storage discharge eliminates CCS parasitic load and maintains CO2 capture rate.

37. Base Fleet Composition • 1,024 units • 228 coal • 383 natural gas • 22 nuclear • 77 wind • 38 solar

38. UCED Data Sources

39. UCED Formulation TC=total costs; p=electricity generation; OC=operating cost; r=offered reserves; ROS=reserve offer scalar; v=turn on; SU=startup cost; nse=non-served energy; CNSE=cost of nse; HR=heat rate; FC=fuel cost; ER=emissions rate; EC=emissions cost; P=demand; R=reserve requirement; PMAX=max capacity; PMIN=min stable load; u=on/off; w=turn off; MDT=min down time; cUP=ramp up; cDOWN=ramp down; RL=ramp limit Minimize Total Operating Costs where: Subject to: Supply = demand Reserves = reserve requirements Unit-specific max and min load constraints Unit-specific minimum up time Unit-specific ramp constraints

40. Full UCED Formulation Objective Function: minimize total operating costs Where: Subject to: Supply=demand

41. Meet reserve requirement foreach type: Supplemental reservesmade of spinning and replacement reserves: Replacement reserves definition: Provided reserves constrainedby spare reserves: Provided reserves constrained byoffer quantity: Spare down reserves constrainedby decrease in generation: Spare up reserves constrainedby available capacity: Spare spinning reserveslimited by available capacityand spare regulation reserves:

42. Generation constrained bymax capacity: Generation constrainedby minimum load: Definition of ramp up anddown variables: Limit ramp up values: Limit ramp down values: Enforce minimum down time: Relate on/off to turn on: Relate turn off to on/off and turn on:

43. Flexible CCS Modeling in Other Papers Generation from Base CCS Generator + Added Flexible Units CCS Retrofit Coal-Fired Generator Original Coal-Fired Generator HR = NetHR = NetHR0*(1+HRPCCS) Continuous Solvent Regeneration Retrofit CCS HR = NetHR0 Constraints Constraints Venting Generator Stored Solvent Pump Unit

44. Full Flexible CCS Formulation

45. Flex CCS: Generation Constraints Between Units

46. Flex CCS: Generation and Reserve Constraints

47. Flex CCS: Solvent Flow Rate and Stored Solvent Volume Constraints

48. Flex CCS: Min Load Constraints

49. Flex CCS: Ramping and On/Off Constraints

50. Flex CCS: On/Off Constraints