Erik Delarue With Pierre Martens and William D’haeseleer

1. Simulating flexible operation of power plants with post-combustion carbon capture in electricity markets Erik Delarue With Pierre Martens and William D’haeseleer University of Leuven (K.U.Leuven), Energy Institute, Leuven, Belgium Contact: erik.delarue@mech.kuleuven.be

2. Overview • Introduction • Post-combustion carbon capture • Analytical analysis • Price based setting • Security constrained setting • Simulation model • Simulation results • Price based setting • Security constrained setting • Summary and conclusions Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

3. Introduction • Carbon Capture and Storage (CCS) • Post combustion capture • Separate CO2 from flue gas • Pre-combustion capture • Use O2 to gasify fuel into H2 and CO2 • IGCC • Oxyfuel • Use O2 for combustion (no N2 in flue gas) Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

4. Introduction • Goal • Discuss market interactions/opportunities of power plants with post-combustion capture • Ultra Super Critical Pulverized Coal USC-PC plant • Natural Gas Combined Cycle NGCC plant • Focus on operational side only • No investments considered • Flexible carbon capture operation assumed • Plants can operate with or without CO2 capture • Both price based and security constrained framework are considered Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

5. Post-combustion carbon capture • Impact of carbon capture on power plant technical characteristics • Operating carbon capture requires steam and power • Main impact, for same fuel input • Net output ↓ • Efficiency ↓ Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

6. Post-combustion carbon capture • USC-PC • Without carbon capture • Pmax = 800 MWe, η = 45.5% • With carbon capture • Pmax = 774 MWe, η = 35.2% • NGCC • Without carbon capture • Pmax = 400 MWe, η = 58% • With carbon capture • Pmax = 350 MWe, η = 50.7% Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

7. Post-combustion carbon capture • Impact on other technical characteristics • Operation and maintenance cost • Start-up/shut-down behavior • Minimum (stable) operating point • Ramp limits • Hot stand-by mode of capture plant? Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

8. Analytical analysisPrice based setting • Marginal cost = sum of fuel, variable O&M and CO2 cost • Without carbon capture • With carbon capture Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

9. Analytical analysisPrice based setting • Marginal cost of operating with or w/o carbon capture Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

10. Analytical analysisPrice based setting • Profit • Recall Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

11. Analytical analysisSecurity constrained setting • If carbon capture is turned off • Additional power • Cost of additional power • Marginal cost of additional power Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

12. Analytical analysisSecurity constrained setting • Marginal cost of additional power, compared to gas turbine Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

13. Simulation model • Mixed Integer Linear Programming (MILP) model • Generation of power plants and possible operation of capture plant are optimized • Price based setting • Maximize Profit = Revenue – Cost • Security constrained setting • Meet given demand, minimize Cost Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

14. Simulation model • High level of technical detail • Model features • Different load levels • Minimum load • Part load efficiency • Ramp limits • Start up cost and start up time dependent on downtime • Detailed representation of different operating modes of NGCC • Flexible operation of capture plant Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

15. Simulation model • Four operating modes for capture plant • Normal operation • Start up • Hot stand-by • Off Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

16. Simulation model • Model is solved with Cplex solver • Using Matlab + GAMS • E.g., model with 4 power plants, 24 h period, time steps of ½ h, security constrained setting • 30,388 equations and 18,052 variables (of which 8,832 discrete). • Model solves in 377 seconds on an Intel(R) Core(TM)2 DUO CPU P9500 @2.54 GHz, with 4.00 GB of RAM Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

17. Simulation resultsPrice based setting • Two power plants considered: • USC-PC • w/o cc 800 MWe, 45.5% • with cc 774 MWe, 35.2% • NGCC • w/o cc 400 MWe, 58 % • with cc 350 MWe, 50.7%  featuring all technical constraints • 24 h price profile • Simulations for different CO2 prices Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

18. Simulation resultsPrice based setting • CO2 price = 30 euro/ton Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

19. Simulation resultsPrice based setting • CO2 price = 40 euro/ton Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

20. Simulation resultsPrice based setting • Overall results Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

21. Simulation resultsSecurity constrained setting • System of 8 power plants considered • Need to meet specified demand at lowest cost Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

22. Simulation resultsSecurity constrained setting • First case is reference • Second case has contingency • Increased load of 600 MW as from 10th hour Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

23. Simulation resultsSecurity constrained setting • Dispatch in reference case • CO2 price = 40 euro/ton Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

24. Simulation resultsSecurity constrained setting • Dispatch in contingency case • CO2 price = 40 euro/ton Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

25. Simulation resultsSecurity constrained setting • Three scenarios considered • Scenario A • Flexible operation of capture plants • Scenario B • Carbon capture mandatory, two additional gas turbines • Scenario C • Flexible operation of capture plants and two additional gas turbines Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

26. Simulation resultsSecurity constrained setting • Operational cost • CO2 emissions Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011

27. Summary and conclusions • Flexible operation of post combustion carbon capture • Price based • Ratio of electricity and CO2 price determines whether to capture or not • Security constrained • Turning off capture plants can provide additional power to the grid • Gas turbines already cheaper at moderate CO2 prices (if present) • Simulation model required to account for power plant technical characteristics and time aspect • In security constrained setting, simulations can become computationally difficult Delarue et al., Flexible operation of CCS plants IAEE Stockholm 2011