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12 pvpmc

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8th PVPMC Workshop, May 9-10 2017

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12 pvpmc

  1. 1. Cell String-Level Energy Production Simulation with Aurora
  2. 2. Powerful software for residential and commercial solar sales and design Founded 2013 Used to create over 10k projects per week 2
  3. 3. Aurora’s Feature Set • 3D modeling with LIDAR and Streetview measurements • Automatic obstruction detection with computer vision • Bankable shade reports using integrated shading engine • Residential and commercial financial analysis • Automatic optimal PV system designer • NEC design validation report • Breakdown of system losses • Sales proposal tool • Electrical line drawings • Submodule performance simulation engine → today’s focus 3
  4. 4. Simulation Types • Array-level • Module-level • Submodule-level 4
  5. 5. A Look Inside a Solar Panel 5
  6. 6. Bypass Diodes and Partial Shading 6 No bypass diodes Shade knocks out entire string of modules One bypass diode Shade knocks out single module Three bypass diodes Shade knocks out single cell string
  7. 7. Submodule-Level Modeling • Most granular model to capture partial shading, bypass diodes, and cell string-level power electronics in modern PV systems – Compute irradiance (S) on and temperature (T) of every cell string in the array – Model each cell string as a circuit, adjust params given (S,T) at a given hour – Solve for MPP by solving (larger) nonlinear circuit 7
  8. 8. Initialize site and panels in 3D space Compute sun position Calculate intersections of rays from sample points to sun with objects Create sample points along every cell string Compute plane of array (POA) irradiance Compute cell string temperature from ambient temp. and incident irradiance For every daylight hour Update equivalent circuit parameters of each cell string (De Soto model) Solve for cell string voltages and string currents; compute output power P Choose initial load on solar array; initialize Pmax = 0 P ≤ Pmax? Done: MPP found at Pmax Adjust load on solar array Yes No 8
  9. 9. 9
  10. 10. Energy Production Results 10 Design Annual Production, Module-Level [MWh] Annual Production, Submodule-Level [MWh] % Difference 3 ft spacing, 154.3 kW 189.50 191.76 1.19% 2.5 ft spacing, 158.9 kW 193.29 196.11 1.45% 2 ft spacing, 177.7 kW 212.66 217.41 2.21% 1.5 ft spacing, 201.0 kW 232.67 241.19 3.60% Module-Level, 1.5 ft spacing Submodule- Level, 1.5 ft spacing
  11. 11. Financial Analysis Results 11 Design Lifetime Energy Bill Savings, Module-Level [$] Lifetime Energy Bill Savings, Submodule-Level [$] % Difference 3 ft spacing, 154.3 kW 575,484 584,718 1.59% 2.5 ft spacing, 158.9 kW 584,958 596,464 1.95% 2 ft spacing, 177.7 kW 640,086 659,581 3.00% 1.5 ft spacing, 201.0 kW 691,797 726,511 4.90%
  12. 12. Why Else Does Submodule Simulation Matter? 12
  13. 13. Unique Cell String Configurations vs. 13 Module power 90 W + 90 W - 5 W = 175 W Module power 90 W + 90 W + 45 W - 5 W = 220 W
  14. 14. Cell String-Level Optimizers vs. 14 Module power 90 W + 90 W - 5 W = 175 W Module power 90 W + 90 W + 45 W = 225 W
  15. 15. Cell String Optimization 15 Without cell string-level optimizers 6.45 MWh With cell string-level optimizers 7.17 MWh
  16. 16. Accuracy 16 NREL Site Average Annual % Error Andre Agassi Prep Academy 2.16% Sanyo Mono Test Array 1.26% RSF1 2.35% RSF2 0.2% Science and Technology Facility 1.8% Month Percent Error [%] Jan 1.9 Feb 0.6 Mar 1.3 Apr -0.1 May -1.0 Jun -0.1 Jul -0.4 Aug -0.4 Sep -0.7 Oct 0.0 Nov 0.4 Dec 3.4
  17. 17. Takeaways • Cell string-level simulation important for assessing performance implications of: – Bypass diodes – Unique cell string configurations – Cell string-level optimizers • 1-3% improvement in accuracy can have significant impact on financial results 17
  18. 18. Additional Resources blog.aurorasolar.com 18 /aurorasolarinc /company/aurora-solar @aurorasolarinc/AuroraSolarInc help.aurorasolar.com www.aurorasolar.com
  19. 19. Backup 19

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