Thermal storage for CSP plants: * concept * functions of the thermal energy storage system (tes) * classification of tes systems * state of the art * future developments Hybridisation of CSP plants: * concept * solar – gas hybrid csp plants * hybridisation with biomass

1. Concentrated Solar Thermal PowerTechnnology TrainingSession 4 – THERMAL STORAGE AND HYBRIDIZATION By Manuel A. Silva Pérezsilva@esi.us.es April 27, 2010 http://www.leonardo-energy.org/csp-training-course-5-lessons

2. ThermalStorageandHybridization Manuel A. Silva Pérez Group of Thermodynamics and Renewable Energy ETSI – University of Seville http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

4. Capacity > 10 MW

5. Typesofutilitygenerators:

6. Base load (nuclear, coal)

7. Dispatchable (gas, CSP)

8. Intermittent (wind, PV)

9. Dispatchability: Theabilitytodispatchpower. Dispatchablegenerationreferstosourcesofelectricitythat can be dispatched at therequestofpowergridoperators; thatis, it can be turnedonor off upondemandhttp://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

10. CSP Markets Distributed generation Capacity: 3 kW to 10 MW Close to consumer Reduces transmission losses Reduces investment in transmission infrastructure Stand-alone applications Modularity, avaliablity, reliability http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

11. ThermalstorageandHybrization CSP unique features within the RE technologies: Thermal energy storage. Thermal energy produced by the solar field can be stored, thus decoupling power generation from solar resource. Hybridization. Ability to hybridize with an alternative energy source –fossil or renewable fuel. Thermal energy storage and/or hybridization provide the basis for CSP to be: Dispatchable Stable Reliable http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

12. Why Energy Storage? Increase operational stability Reduce intermittence. Increase plant utilization and capacity factor Provides “peak-shaving” ability (time-shifted operation) Reduce generation cost (as long as storage is cheaper than increasing rated power!) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

13. Profile of the electricity demand http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

14. Solar-only electricity generation http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

15. Solar + Thermal Storage http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

16. Thermal energy storage A fraction of the thermal energy produced at the solar field is stored, increasing the internal energy of the storage medium. Sensible heat Latent heat (Thermochemical) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

17. Types of thermal storage By utilization Short term Provide operational stability Medium term Increase capacity factor Shift electrical generation hours By type Direct (same substance as working fluid, does not require HX) Indirect (different substance, requires HX) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

18. Technical Requirements for TES materials High energy density (per-unit mass or per-unit volume) Good heat conductivity Good heat transfer between heat transfer fluid (HTF) and the storage medium Mechanical and chemical stability Chemical compatibility between HTF, heat exchanger and/or storage medium Reversibility for a large number of charging/discharging cycles Low thermal losses Easy to control http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

19. Thermal storage options Source: Survey of thermal storage for parabolic trough power plants, Pilkington Solar Int. (2000) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

20. Thermal storage past experiences Source: Survey of thermal storage for parabolic trough power plants, Pilkington Solar Int. (2000)

21. TES – STP commercial installations Short term: pressurized water PS10 and PS20 Mid term: Molten salt, 2 tank Direct (CRS) – Gema Solar (Solar Tres) Indirect (PT) – Andasol I http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

23. Thermal capacity: 20 MWh (50 min at 50% load)

24. Total Volume: 600 m3

25. 4 tanks, sequentially operatedhttp://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

27. Need for heat – tracing (risk of freezing)

28. Costly equipment (pumps, valves…http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

30. Intermediate oil-to-salt HX

31. Freezing Temp = 220 oC

32. High temp. limited by HTF

33. Large volumes

34. Higher investment costshttp://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

35. Andasol storage -Technical characteristics Type: 2-Tank Molten Salt Storage Fluid: Nitrate salt mixture (60% NaNO3 and 40% KNO3) Melting Point: 223°C Storage Capacity: 1,010 MWh (~7.5 hrs full load operation) Storage Tank Size: 14 m height 37 m diameter Salt Mass: 27,500 tons Flow Rate: 953 kg/s Cold Tank Temperature: 292° C Hot Tank Temperature: 386°C http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

36. ANDASOL, Moltensalt 2-tank TES http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

37. TES – advanced experiences http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

38. TES – advanced experiences http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

39. TES costsandbenefits Improves plant controlability and operability, expanding de range of possible operating strategies Facilitates Dispatchability If adequately designed, can improve The efficiency of the plant The profitability of the project Extends lifetime of equipment (reduces the number of strat-stop cycles) Increases investment Oversized solar field Tanks, HX, molten salt management equipment, heat tracing, safety Increases O&M costs http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

41. Solar energy

42. Fossil or renewable fuel

43. Hybridisation of STP plant

44. Eases plant operation during transients

45. Eases turbine startup

46. Reduces number of turbine stops

47. Increases full-load operation time

48. Can be used to maintain temperature of HTF or storage mediumhttp://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

49. Hybridization options http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

50. SEGS 30 MW http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

51. ANDASOL-TYPE PLANTS (THERMAL STORAGE AND AUXILIARY BOILER) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

52. ISCCS 3 projects in North Africa (Morocco, Algeria, Egypt) http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

53. HybridizationCostsandbenefits Improves controlability and operability Faciltates dispatchability Improves plant overall efficiency Improves capacity factor Improves profitability of the plant Extends equipment lifetime Increases investment and O&M costs CO2 emmissions http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization

54. Thanksforyourattention! http://www.leonardo-energy.org/csp-training-course-lesson-4-thermal-storage-and-hybridization