CSP Parabolic Trough Technology for Brazil A comprehensive documentation on the current state of the art of parabolic trough collector technology

Transcription

1 CSP Parabolic Trough Technology for Brazil A comprehensive documentation on the current state of the art of parabolic trough collector technology Seite 1

2 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 2

3 In 45 minutes, the sun sends more energy to the earth than humans consume in an entire year. With solar power plants more power can be generated on only 1% of the earth s deserts than fossil fuels produce globally today. The future belongs to whoever succeeds in using these reserves effectively and profitably. Investing here is investing in the market of the future. Our future energy supply must be based on the use of renewable energies. Solar power plants make a valuable contribution to a sustainable and climate-friendly generation of energy. Concentrating Solar Power (CSP) allows to convert the existing solar energy into dispatchable electricity. Introduction Seite 3

4 Projects under construction, commissioning or operational Technology split of global CSP projects under construction, commissioning or already operational as of Dec Dish 707 Fresnel 4, Parabolic Trough Power Tower Source: CSP Today Global Tracker, December 2013 Parabolic Troughs are the single most important technology used. Introduction Seite 4

5 Brazil Saudi Arabia California Andasol /Spain Stuttgart Implemented by Dish Stirling Parabolic Trough 500 m from tower towards pole Fresnel Tower 500m East/West Tower Height 180 m 500 m from tower towards equator Comparison of CSP Technologies Seite 5

6 LCOE [ /kwh] Implemented by Brazil: Direct Normal Irradiation (DNI) at a high level. Higher DNI leads to lower levelized cost of electricity (LCoE). 0,35 LCOE and direct normal iradiance (DNI) 0,30 0,25 0,20 0,15 0,10 0,05 0, DNI [W/(m^2 * a)] design output: 50 MW storage: 6 h O&M and insurance: 3 % of total investment Operation time: 25 years Interest Rate : 8 % Solar Irradiance and LCOE Seite 6

7 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 7

8 early 20th century First 45 kw parabolic trough collector plant by Shuman and Boys 80ies First commercial parabolic trough power plants in the Mojave Dessert in California (SEGS) 2004 Introduction of feed in tariff (FIT) by the Spanish government 2008 Andasol: first commercial parabolic trough power plant in Europe History Seite 8

9 Andasol Plants (2009) Seite 9

10 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 10

11 The trough is tracking the sun on a single axis (elevation axis) Direct radiation is focused on an absorber tube A heat transfer fluid is pumped through the absorber tube and is heated up Steam is produced and runs a turbine Heat is stored in storage tanks to produce electricity on demand P rin c ip le of a S o la r P a ra b olic T ro u g h P ower P la nt Seite 11

12 Parabolic trough power plant functional principle Seite 12

13 Pros short distance between reflector and absorber tube low energy losses delivers dispatchable energy Cons limited operation temperature (by heat transfer fluid) higher cosine losses than dish even terrain required proven technology bankable lower part costs lower LCoE low area demand low energy losses easy to scale 10 MW to 250 MW Pros and cons of parabolic troughs Seite 13

14 Torque Tube Torque Box Space Frame Steel Aluminum + high stiffness and strengths + low thermal expansion -- high mass + low mass -- low stiffness -- high thermal expansion Supporting Structure Seite 14

15 Genealogy of parabolic trough collectors Seite 15

16 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 16

17 LS-2: - torque tube design - able to achieve good optical accuracy - easy to assemble - good optical performance - high costs - aperture width: 5 m - SCE: 7.8 m - SCE per SCA: 6 - SCA length: 47 m LS-3: - Space frame truss design - 2x as long and larger aperture - inadequate torsion stiffness - cost savings not demonstrated - lower optical performance - aperture width: 5.76 m - SCE: 12 m - SCE per SCA: 8 - SCA length: 96 m First commercial collector generation Seite 17

18 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 18

19 Solar Collector Element (SCE) Structure: Torque boxes Length: 12 m Aperture width (gross): 5.76 m Aperture area (net): 68 m² HCE Diameter: 70 mm Solar Collector Assembly SCA SCA: 12 SCE per SCA Length: 150 m Aperture area: 816 m² Drive: Hydraulic drive system Euro Trough Key figures Seite 19

20 SENERtrough: - torque tube supported on sleeve bearings - stamped arms to support the reflector panels - most common collector today - aperture width: SCE length: 12 m - SCA length: 150 m ENEA collector: - torque tube as main structure element - molten salt as heat transfer fluid - reflector panels: special aluminum honeycomb facet with thin glass mirrors - aperture width: 5.76 m - SCA length: 100 m Currently available parabolic trough collectors Seite 20

21 Solargenix (SGX-2): - used in Nevada Solar one, Nevada - extruded aluminum space frame - easy to assemble - aperture width: 5 m - SCE length: 8 m - SCA length: 96 m Currently available parabolic trough collectors Seite 21

22 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 22

23 HelioTrough: - torque tube with constant stiffness along the whole collector - reduced number of parts (mirrors, HCE etc.) - increased lifetime - cost reduction of maintenance and assembly - improved optical efficiency - aperture width: 6.78 m, - aperture area: 1263 m² - SCE length: 19 m / SCA length: 191 m - developed by: sbp and Flagsol Ultimate Trough: - world s largest collector - peak optical efficiency of 82.7 % - truss toque box design - continuous mirror surface - economic use of material - high stiffness allows increased span of 24.5 m - aperture: 7.51 m, aperture area: 1716 m² - SCE length: 24.6 m, SCA length: 240 m - total solar field cost savings up to 20 % - developed by: sbp, Flabeg (German consortium) Recent collector developments Seite 23

24 SENERtrough-2: - torque tube - increased aperture width, collector element length and focal length - drive pylon structure: vertical pipe - aperture width: 6.87; aperture area: 1048 m² - SCE length: 13.2 m - SCA length: 158 m SkyTrough: - aluminum space frame - reflective polymer mirror film attached on an aluminum sheet instead of glass reflector panels - aperture width: 6 m; aperture area 656 m² - SCE length: 14 m - SCA length: 115 m - developed by: Skyfuel Recent collector developments Seite 24

25 Large Aperture Trough (LAT 73): - aluminum space frame - reflective polymer film on aluminum back sheet - aperture width: 7.3 m; aperture area: 1392 m² - SCE length: 12 m - SCA length: 192 m - developed by Gossamer Space Frames and 3M Abengoa E2: - steel space frame collector - aperture width: 5.76 m (LS-3) - SCA length: 125 m - monolithic glass reflector panels Recent collector developments Seite 25

26 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 26

27 LCOE [ /kwh] Implemented by Overall performance value Usually used to compare different options for power generation Calculation: Total investment costs incl. all expenses (e.g. O&M, taxes, insurance) divided by cumulated electric energy produced during the complete operational time Unit: / kwh Parametric calculation to show the impact of the DNI on the LCOE (50 MW with 6 h storage) 0,35 0,30 0,25 0,20 LCOE and direct normal iradiance (DNI) 0,15 0,10 0,05 0, DNI [W/(m^2 * a)] design output: 50 MW storage: 6 h O&M and insurance: 3 % of total investment Operation time: 25 years Interest Rate : 8 % Levelized Cost of Electricity LCoE Seite 27

28 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 28

29 For comparison, the LCoE for three plant sizes is calculated. Boundary conditions: EuroTrough collector (established, reliable performance data) solar irradiance (DNI): 2500 W/m² with and without thermal storage operational period: 25 years Investment costs Earth works & Foundations Parabolic trough costs HTF system (with HTF) other solar field costs power block storage EPC costs Owner costs spec. Investments annuity of investment costs O&M costs and insurance spec. O&M costs Total annual costs LCOE 50 MW 50 MW 100 MW 100 MW 200 MW 200 MW 6 h Storage w/o Storage 6 h Storage w/o Storage 6 h Storage w/o Storage M M M M M M M M M M /MW M M k /MW/a M /a /kwh 0,108 0,111 0,098 0,102 0,094 0,095 Comparison of parabolic troughs power plants Seite 29

30 LCOE, normalized[%] Implemented by LCOE (normalized ): impact of TES and up-scaling without TES with TES design output [MW] LCoE can be reduced by power plant scale-up (parabolic trough collector scale-up not considered here) integration of thermal storage (increased controllability, utilization of the turbine) (LCOE normalized to 50MW design output and without TES) Comparison of parabolic troughs power plants Seite 30

31 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 31

32 1 300 m m Implemented by EuroTrough, m² UltimateTrough, m² m m Header piping ET UT Ratio north-south [m] 1'678 n/a east-west [m] 6'840 3'757 55% total [m] 8'518 3'757 44% HFT volume [m³] 1'813 1'353 75% The Ultimate Trough shows a cost reduction of about 20 to 25 % compared to the EuroTrough by: decreasing specific solar field cost [ /m²] by going large increased of optical performance (8 %) by stress free mirror attachment Due to increased collector dimensions and optical performance one UT loop will have more than twice the thermal power compared with ET loop. General trends: Cost reductions due to collector scale up Seite 32

33 Significant cost reduction due to: Collector Type EuroTrough Ultimate Trough Ratio UT/ET Number of loop specific parts (drives, sensors, local control board, cabling, swivel joints, control & separation valves, loop interconnection piping) significantly reduced by 50 to 60 % Less piping (material, installation, insulation) Less heat transfer fluid Lower installation, commissioning and operation cost Aperture Width m % SCE length m % SCA per SCA # % SCA length m % Aperture Area / SCA m² , % Solar field m² 510, ,731 91,5% Capacity (gross) 8 h storage MW % Loops # % SCE # 7,296 2,720 37% Drives/ Sensors/ Controls # % Pylon foundations # 7,800 2,992 38% Swivel joint assemblies # 1, % Cross over pipes # % General trends: Cost reductions due to collector scale up Seite 33

34 Large scale Innovative design High optical accuracy low specific cost [ /m²] for structure, civil works and assembly by going large m aperture (Ultimate Trough) significant reduction of parts with related cost savings the amount of heat transfer fluid (HTF) is reduced by 25 % overall solar field costs about 23 % less compared to EuroTrough LCoE is decreased by about 11 % compared to EuroTrough Steel structure with low accuracy allows effective sourcing Simplicity in assembly allows low skilled labor requirements and time efficiency Cost Reduction by 20-25% (Compared to the currently available EuroTrough collector) Close to perfect - Intercept factor mm HCE mm HCE Optimized for molten salt systems for higher energy efficiency General trends: Cost reductions due to collector scale up Source: Riffelmann et al., Performance of the Ultimate Trough Collector with Molten Salts as Heat Transfer Fluid, SolarPACES 2012, Marrakesh, September 2012 Seite 34

35 Net annual energy [GWh] Implemented by The Ultimate Trough collector is ready for molten salt operation: The higher concentration factor using a 70 mm receiver tube compensates the higher thermal losses at elevated temperatures while the intercept remains high at 97.5 %. This leads to a significantly higher thermal efficiency compared to troughs with a lower concentration ratio. Electrical isolation of HCE for impedance heating is available HCE supports suitable for higher expansion length due to elevated temperatures are available Higher operating temperature Requires higher concentration ratio Requires higher optical performance HCE diameter [mm] The commonly available receiver diameter of 70mm is the optimum diameter for the Ultimate Trough high-aperture collector for use with molten salt. The graph shows that the maximum annual yield of a given power plant (120 MW gross output and 14 h of thermal storage, located in Daggett, U.S.) is highest for a receiver diameter of 70 mm. Source: Riffelmann et al., Performance of the Ultimate Trough Collector with Molten Salts as Heat Transfer Fluid, SolarPACES 2012, Marrakesh, September 2012 General trends: Cost reductions due to higher operation temperatures Seite 35

36 18 16,9-9 % -10 % ,4 13,9-20 % 11,2-10 % 10,2-40 % LCoE Daggett [ -Cent/kWh] Seite 36

37 1. Introduction 1.1. History 1.2. Aspects for Parabolic Trough Design 2. Overview on Parabolic Trough Collectors 2.1. First Commercial Collector Generation 2.2. Currently Available Parabolic Trough Collectors 2.3. Recent Collector Developments 3. Financial Parameters 3.1. Levelized Cost of Electricity 3.2. Comparison of Parabolic Trough Power Plants 4. Technological Developments 4.1. General Trends 4.2. Further Cost Reduction Potential Content Seite 37

38 Reflectors: Absorber tubes (HCEs): significant cost reductions in glass mirror manufacturing manufacturers increase accuracy and reflectivity anti-soiling coating reduce O&M costs new reflector concepts: reflecting film / composite facets manufacturers increase production procedures due to competition reduction of thermal losses by using new procedures development targets higher temperatures (> 500 C) for molten salt application Metal support structure: Drives and control: larger structures allows for smaller solar fields this significantly reduces number of parts cost savings (e.g. drives, pylons, sensors, controls) various drive concepts have been conceived and tested hydraulic drives are the most cost efficient solution manufacturers increase production procedures due to competition Further cost reduction potential Seite 38

39 Parabolic Trough technology is a proven technology with a long track record. Performance and cost estimates for Parabolic Trough technology are based on validated performance models and build projects It provides the production of dispatchable renewable energy at currently lowest possible cost. And yes, there is still room for improvement: There is still not enough development, testing, and standardization. HTF technology, not only molten salt, is a key to further cost reduction. The Ultimate Trough is just one step in the required direction The low deployment of the technology as of now allows significant cost reductions through economies of scale in future projects. Conclusion Seite 39

40 As a federal enterprise, GIZ supports the German Government in achieving its objectives in the field of international cooperation for sustainable development. Published by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH Registered offices, Bonn and Eschborn, Germany CSP Parabolic Trough Technology for Brazil Address of Programme here T E giz-brasilien@giz.de I Responsible schlaich bergermann und partner, sbp sonne gmbh Author(s) Finn von Reeken, Sarah Arbes, Dr. Gerhard Weinrebe, Markus Wöhrbach, Jonathan Finkbeiner Photo credits GIZ/schlaich bergermann und partner In cooperation with Contact Details Seite 40