1. 1 Economic, CO2 and Security performance of power system operation with carbon capture plant and renewable generation (Theme A5 - UK Real Time Energy Supply and CCS Plant) Anser Shakoor, Cheeyong Chen, Goran Strbac (Imperial College London) (UKCCSC meeting – Nottingham- 18 April 2007)

2. 2 Presentation Outline Objectives Modelling CC technologies Case studies Results

3. 3 Project Objectives: Development and implementation of a simulation (system operation) platform to evaluate the cost, CO2 and security performance of UK power generation system, with carbon capture applied to conventional (fossil fuelled) generation.

4. 4 How the introduction of carbon capture technologies impact on the technical, economic and environmental performance of UK generation system? How the combination of carbon capture process and high penetration of intermittent renewable (wind) generation influence the UK power system operation? Key Questions:

5. 5 Modelling CC Technologies -1 a - Post Combustion Capture Approx. 85% CO2 is removed through amine scrubbing of flue gases. Does not alter the combustion process and provides flexibility Solvent regeneration & CO2 compression is required that needs large amount of energy (~ 10% of plant capacity effected) Option-1: store solvent thus reclaiming plant capacity during high demand periods, with later regeneration during low demand periods. Option-2: stop carbon capture during high demand periods (associated with high CO2 release to atmosphere).

6. 6 Summary of different modes of operation in post combustion CC Mode of Operation / Generator Characteristics Minimum Stable Generation (MSG) MW Generator Registered Capacity (GRC) MW CO2 Release (%) Without Capture (simple venting) 250500100 With Capture (Regeneration) 22545010 With Capture (Solvent Storage with No Regeneration) 25050010 With Capture (Regeneration + stored solvent regeneration) 20040010 Modelling CC Technologies -2

7. 7 b – Pre Combustion Capture Uses fuel conversion before combustion/conversion Operating characteristics of pre combustion plant (less flexible) is very different from post combustion plant Can not be operated like solvent storage in post combustion as continuous removal of CO2 is required (also high pressure vessel req.). Limited gain of simple venting as most of the CC related energy is consumed before removal of carbon. Plants with pre combustion carbon capture are modelled as inflexible with 10% reduction in their output Modelling CC Technologies -3

8. 8 System Description -1 Demand: Pk. Demand = 57 GW, Min. Demand = 18GW Annual hourly demand profile considering 6 characteristic days, three seasons (winter, summer and spring/autumn) and two types of days (business and non business day). Demand is assumed to be fully predictable (i.e., impact of demand forecasting error is not included).

9. 9 System Description -2 THERMAL SYSTEMS ParametersInflexible Generation Moderate flexibility Generation Flexible Generation Low Flexibility (LF) MSG100%77%50% Capacity installed 9.5GW26GW>25.6GW Medium Flexibility (MF) MSG100%62%50% Capacity installed 9.5GW26GW>25.6GW Generation System WIND GENERATION: Annual hourly generic UK wind generation profile is used to represent 26 GW (20%) of wind generation capacity installed

10. 10 Reserve Requirement & Provision Two cases of reserve provision: i.Entire reserve provided by synchronised plant ii.Part of reserve provided by conventional synchronised plant and rest by standing reserve form; a) OCGTs, b) Carbon capture plant Amount of reserve req. derived from the standard deviation of wind variations (4-hr time horizon) No. of Standard Deviation in wind variation Wind output forecast error (MW) Operating Reserve Requirement (MW) Maximum Spinning Reserve (MW) Maximum Standing Reserve (MW) Standing Reserve from OCGT (MW) Standing Reserve from CCS (MW) 3.524158451 000 2.524156036 25001550950 2.324155554 30002050950 224154829 35002550950 1.724154105 45003550950

11. 11 Model Output Simulation of system operation (hour by hour, year round) with 26 GW of wind capacity, taking into consideration daily and seasonal demand changes and variations in wind output provides the following key output per annum. - energy produced by conventional plant - CO2 emissions - generation cost including cost associated with carrying spinning reserve - energy not supplied (due to insufficient reserves and constraints on ramp rates) - wind generation curtailed (due to minimum stable generation constraints and constraints on ramp rates) - energy produced by OCGTs (when OCGT plant is used)

12. 12 Preliminary Results

13. 13 Total Standing Reserve Capacity (MW) OCGT Capacity (MW) CCS Capacity (MW) Low Flexibility System ( £m/pa ) Medium Flexibility System ( £m/pa ) 25001550950196189 30002050950243232 35002550950316298 45003550950395366 Reduction in fuel cost 10% (950MW) of the total CC plant capacity is available for provision of standing reserve Assumption: cost of OCGT is 50£/MWh (in contrast to marginal cost of synchronised plant of 20£/MWh)

14. 14 Reduction in CO2 Emissions Total Standing Reserve Capacity (MW) OCGT Capacity (MW) CCS Capacity (MW) Low Flexibility System ( tonnes/pa ) Medium Flexibility System ( tonnes/pa ) 250013609503,926,3613,792,819 300018609504,872,4264,663,161 350023609506,379,4516,013,640 450033609508,008,4347,427,662 Assuming that standing reserve plant emit 0.6 tonne/MWh compared to 0.4 tonne/MWh by synchronised plant.

15. 15 Reduction in thermal energy / Increase in Utilization of Wind energy Total Standing Reserve Capacity (MW) OCGT Capacity (MW) CCS Capacity (MW) Low Flexibility System ( MWh/pa ) Medium Flexibility System ( MWh/pa ) 250013609505,117,4972,191,325 300018609506,103,8472,555,790 350023609507,476,2733,042,481 450033609508,722,8233,464,049

16. 16 Further Work Model enhancement including: Effect of demand forecast errors Reserve req. assessment based on temporal wind & demand level Oxy fuels Start-up costs…. Further studies involving real systems, levels of system security, fuel prices, …… Documentation of developed model and results (report)

17. 17 Economic, CO2 and Security performance of power system operation with carbon capture plant and renewable generation (Theme A5 - UK Real Time Energy Supply and CCS Plant) Anser Shakoor, Cheeyong Chen, Goran Strbac (Imperial College London) (UKCCSC meeting – Nottingham- 18 April 2007)