Parabolic Trough, Linear Fresnel, Power Tower. A Technology Comparison. Robert Pitz-Paal

Transcription

1 Parabolic Trough, Linear Fresnel, Power Tower A Technology Comparison Robert Pitz-Paal

2 Thermal Storage vs. Electric Storage η >95 % h 2000 h 200 h CSP with storage and fossil hybridisation can provide all 3 components of value Thermal storage economically favorable η

3 Cost of electricity for CSP system with and without storage 0.1 Euro/kWh 0.15 no storage solar multiple (s m ) storage 12 h rated power Electricity generation cost as function of solar multiple and storage size

4 4 How does CSP react under desert conditions? Water consumption Mirror washing 2.0% Recycling Steam cycle 6.1% Dry cooling Cooling tower 91.8% Potable water 0.1% Washing (no recycling yet) 75 l / MWh (low soil.) 30 l /m² year (mirror surface) 0,5 l/m² per wasching cycle Rainfall Cairo = 25 l/m²year Reflector Degradation? Glass mirrors have proven high robustness over >25 years in operation DLR has established accelerated aging methods for specific reflector types Reflector Soiling Cleaning of CSP collectors on a weekly basis, Soiling depends strongly on site (and seasonal) conditions. Variations can be in the order of a factor 2-3 5% average soiling leads to revenue losses of 3-6 $/ m²year (depending on electricity price) Cleaning need l/m² year

5 Chart 5 Land use (m²/mwh/a)

6 Chart 6 Efficiency Potential of CSP Systems η max = η th,carnot * η absorber Parabolic Dish Solar Tower η max Parabolic Trough Flat Plate Collector (T absorber =T process ) [K]

7 Chart 7 Market Situation Ground Requirements

8 Chart 8 Parabolic Trough Plant Scheme Solar Field parabolic trough collector field m 2 Heat Transfer & Buffer 2-10 hours capacity Power Block steam cycle turbine, condenser MW

9 Chart 9 Line Concentrators how do they work?

10 Chart 10 Line Concentrating Collectors 1-dimensional curvature of reflector short focal distance mirror bending required receiver length equals collector length absorber typically a tube heat flux rates MW/m² absorber temperature limited to C absorber insulation required (glass) parallel rows, only horizontal installation economical heat transfer fluids: synthetic oil, water/steam, molten salt, (CO 2 ) hydraulic and thermodynamic design to operating conditions heat storage possible net solar-to-electric peak efficiency 20-28% process heat applications performance modeling is state of the art

11 Chart 11 Linear Fresnel Collector Working Scheme secondary concentrator insulation receiver absorber tube glass window mirror rows

12 Chart 12 Linear Fresnel Collector - Properties off-axis, astigmatism gaps to reduce shading/blocking flat glass, light weight less standardized than troughs max theoretical concentration and optical efficiency lower than troughs collector width up to 20 m focal length up to 30 m fix receiver distance between rows 30-40% capture 55-65% of DNI two-axis incidence angle impact low performance on sun rise/set, high at noon low wind forces (low height) first commercial plants (Novatec, Areva, )

13 Chart 13 What is the difference between Parabolic Trough and Linear Fresnel? 64% 64% Verluste LFK Verluste Eurotrough 56% 43% 26% 15% 12% 9% 9% 4% 5% 3% 2% 2% opt. Verluste Wärmeverluste Anfahrverluste unteres Dumping 70% 60% 50% 40% 30% 20% 10% 0% Powerblock Eigenbedarf oberes Dumping

14 Chart 14 Why higher optical losses?

15 Chart 15 Why more dumping losses? 15. Jun Parabolic Trough Collector max. power dumping min. power dumping used power DNI 700 energy in kwh Jun DNI in W/m² max. power dumping min. power 300 dumping used power DNI 200 Linear Fresnel Collector local time energy in kwh DNI in W/m² local time 0

16 Chart 16

17 Chart 17

18 Chart 18 LCOE of Parabolic Trough (Algeria 2400kWh/m²a)

19 Chart 19 Concept of Tower Technology Storage

20 Chart 20 Solar Tower

21 Chart 21 Solar Tower Steam, Molten Salt Ivanpah-CA 3x123 MW Brightsource Tonopah-NV 110 MW SolarReserve Lancaster-CA 5 / 46 MW esolar

22 Chart 22 Heliostats

23 Chart 23 Receiver Concepts

24 Chart 24 Solar Tower, molten salt Gemasolar 20 MW Torresol Spain Hot Salt Storage Tank 565 o C Cold Salt Storage Tank 290 o C Steam Generator Conventional EPGS

25 Ivenpah 25 Solarturm Projekt

26 Chart 26 Example Reference Plant Molten-Salt Tower 100 MW Algeria

27 Chart 27 Atmospheric Extinction between Heliostat and Receiver Receiver Scattermeter Transmitter LIDAR

28 Chart 28 Aerosol Concentration close to ground surface

29 Slide 29 / Solar Tower Modularity & Scalability

30 Chart 30 Conclusions Trough Tower and Fresnel Systems have very different characteristics and require complex design tools for their layout All three technologies have a realistic market potential and can further reduce costs

31 Chart 31 GIZ Renewable Energy Week > CSP Overview > Dr. Eckhard Luepfert, DLR Institute of Solar Research, Berlin 09/2012 DLR - Institute of Solar Research

32 Chart 32 Solar Tower Jülich Solair/HitRec Air as Heat Transfer Fluid 1.5 MW DLR / KA München Receiver Hot Air 730º Steam Generator Storage ~ Heliostats Cold Air 110º Super heated Steam