Solar Power Systems

1. Solar Power Systems

2. Energy from the Sun

3. Solar Energy

4. Practical Uses of Solar Energy

5. Solar Water Heaters

6. Photovoltaic Development Russell Ohl 1940 Edmund Becquerel 1839 Gerald Pearson, Daryl Chapin, and Calvin Fuller 1953 William Grylls Adams 1876

7. Space Race Saves PV Vanguard I Satellite 1958 One Watt Telstar Satellite 1962 14 Watts

8. From Novelty to Real World Applications Buoys and Lighthouses Offshore Oil Platforms RR Crossings Rex, GA 1974

9. P-N Junction

10. Photovoltaic cell

11. Diode current 5 External circuit – Diode Amps (e.g. , battery, BV V - Isc A ( e 1 ) lights) + I 0 Diode Volts 0.0 0.6 Electrical Properties of a Solar Cell I – V Curves

12. Terms • Solar Irradiance (density), average 1 kW per square meter at noon on a clear day at sea level • Solar Insolation: hours per day that solar panel delivers rated voltage, varies seasonally • STC: standard test conditions, 25° C, 1 kW per square meter irradiance & AM 1.5 • AM: Air Mass, density & clarity of air sunlight passes through to reach the modules

13. PV Panel Ratings Nameplate (STC) Rating Field Rating

14. The PV Cell & Panel Families Polycrystalline Panel Monocrystalline Panel Thin Film Panel

15. PV Cells and Panel Assembly

16. Monocrystalline Panel

17. Polycrystalline Panel

18. Thin Film Panel

19. PV Basics

20. PV Panel Arrangements • 36 Cells in Series Make a 12V-Class Panel (Voc  19V) 9 cells x 4 cells is a common configuration • Two 12V-Class Panels in Series Make a 24V-Class Array (Voc  38V) • 60 Cells (5x12) in Series Make a 30.2V Nominal Panel (Voc  36.8V)

21. PV Systems Utility Intertie Stand alone direct connected

22. Stand alone PV System

23. Typical Grid Tie without Battery

24. 20 panel 2.5 kW PV System Santa Rosa CA TOU Meter DC Disconnect & Inverter

25. Metering Data TOU rate 31¢/kwh Noon to 6PM (peak solar production); non-peak rate 11¢/kwh

26. Quantifying the Resource

27. Location, Location, Location

28. PV Mounting Systems • Does your site location need to meet special building requirements? • What is the maximum wind speed that it must be designed for? • What is the maximum snow loading that it must be designed for? • What structures best use the soil type in your area? • Can you drive piers directly into the ground or do you need concrete? This will require a geotechnical study of the site and can result in a significant cost savings. • Can you use a ballasted system? • What height does your system need to be to avoid being covered by snow, or vegetation? • If you decide to track, what are the lowest temperatures that system will see?

30. Single Axis Tracking

31. Tracker A: Individual drive for each row. Electric screw jack drive Backtracking controller Variable spacing between rows Height can be modified by user Site welding required Tracker B: Single drive for multiple rows Electric screw jack drive Backtracking controller Height limited by size of support columns and Drive support. Fixed row spacing Site welding required Site needs to be flat and level

32. Tracker C: Single drive for multiple rows Electric screw jack drive Backtracking controller Height limited by size of support columns and Drive support. Fixed row spacing Site welding required Site needs to be flat and level Tracker D: Single drive for multiple units Electric screw jack drive Backtracking controller Height limited by size of support Fixed row and column spacing Site welding required Site needs to be flat and level

33. A 2 AXIS C 2 axis B 2 AXIS

34. Your roof top is valuable real estate, without the permitting problems associated with brownfield installations Rack PV roof mounting system Accepts most standard PV Roof loading dependent on tilt angle From 2 lbs/ft 2 with penetrations to a ballasted system with no penetrations.

35. Examples of Roof Top Installs Phizer = KW 337 Tilt Angle 5 deg. Number of Modules 1,372 California Residence 2.5 kW, 20 panels

36. PV ARRAY 10 strings in parallel form an array 14 modules in series forms one string Combiner box DC Circuit Combiner Inverter Input

37. 1 MW PV Array

38. Sub Array Combiner Box with String Monitoring

39. Field Combiner Boxes

40. Grid Tie Inverter

41. Grid Tie Inverters The grid tie inverter must synchronize its voltage & frequency with that of the grid. A typical modern GTI has a fixed unity power factor. Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down. This requirement ensures that in the event of a blackout, the inverter will shut down to prevent harm to line workers who are sent to fix the power grid. Peak power tracking voltage: This represents the DC voltage range in which the inverter will operate. The designer must configure the strings so that during the majority of the year, the voltage of the strings will be within this range. This can be a difficult task since voltage will fluctuate with changes in temperature. Most grid-tie inverters include a maximum power point tracker on the input side that enables the inverter to extract an optimal amount of power from its intended power source.

42. Prewired System with Inverter, Transformer & Fused Combiner Boxes

48. Concentrated Solar Power CSP

49. Rick Downer – POWER Engineers Inc. IEEE IAS April 18, 2011