The Critical Role of PV Material Durability to Ensure System Longevity Solar Energy UK October, 2014 Birmingham

Transcription

1 The Critical Role of PV Material Durability to Ensure System Longevity Solar Energy UK October, 2014 Birmingham Stephan Padlewski Marketing Manager, EMEA DuPont Photovoltaic Solutions

2 DuPont Photovoltaic Materials Solamet Metallization Pastes Tedlar PVF Films for Backsheet DuPont Ionomer Encapsulants Driving higher energy conversion efficiency Protecting PV modules Delivering long-term protection of cells DuPont has been ranked among the top 10 companies for solar energy patent grants 40 Year track record in photovoltaic materials, service and support 77

3 14 Solar Plants on DuPont Sites 11 Million kwh/year Shenzhen, China Taoyuan, Taiwan Hyderabad, India Rooftop Thin Film Rooftop c-si Rooftop Thin Film & c-si Wilmington, DE, USA Cernay, France Ground Mount c-si Rooftop Thin Film Ground Mount c-si Waimea, HI, USA Tlalnepantla, Mexico Parlin, NJ, USA Ground Mount c-si Ground Mount Thin Film Ground Mount c-si & Thin Film DuPont

4 3 Areas Driving Next Wave of Growth in Solar Efficiency Lifetime Cost Continuous cell performance improvement from innovative materials Safe, in-spec power generation for 25 or more years Continuous improvement in material content cost, laydown and system designs 79

5 LCOE Reduction through Efficiency Improvement Roadmap N-type Cells Bi-facial: Solamet PV3Nx IBC:One paste solution Efficiency (%) Conventional Cells Solamet PV14x New LBSF (LDE) Architectures Solamet PV36x High Efficiency Cells Solamet PV15x, 16x Back Contact MWT : Solamet PV70x, PV71x High Efficiency LDE Cells Solamet PV17x, 18x Year DuPont Solamet metallization technology is on target to help achieve 22% cell efficiency in

6 Impressive Track Record of Solamet Paste Technology Approx. 70% reduction in metal laydown Source: DuPont 81

7 3 Areas Driving Next Wave of Growth in Solar Efficiency Lifetime Cost Continuous cell performance improvement from innovative materials Safe, in-spec power generation for 25 or more years Continuous improvement in material content cost, laydown and system designs 82

8 System Lifetime Impacts Investment Returns Three factors significantly impact system lifetime bill of materials, component design and manufacturing practices 8

9 DuPont Ionomer Na+ Shield to Prevent PID Degradation Ionomers ~0% EVAs >>5% 85C / 85% / -1000V um Ionomer film between EVA and glass prevents PID Ionomers pass 500 hrs of simulated PID test (Strd test is 96 hrs) EVA-based encapsulants show severe degradation, even PID-resistant EVAs PID-free performance has been validated at several potential customers Source: DuPont-Yingli EU PVSEC

10 Industry Standards not Reflecting Long-term Performance IEC testing protocols do not adequately simulate the rooftop stress environment Qualification Tests 1 to 2 stresses in series 15 kwh per m2 of UV radiation (front) no irradiation on the back 200 thermal cycles No solar load (not in operation) in testing chambers 25 Years In-Field Multiple environmental and mechanical stresses 171 kwh per m2 rear side of UV radiation (temperate) * 1000s of thermal cycles Higher operating temperature Stresses endured with solar load (in operation) Long-term outdoor exposure is the ultimate test for all module components, material quality and manufacturing quality. * * Artur Skoczek, Tony Sample and Ewan D. Dunlop, The Results of Performance Measurements of Fieldaged Crystalline Silicon Photovoltaic Modules, Wiley InterScience,

11 Stress Intensity: Operating Temperature Type of module installation impacts thermal stress level +15 º C +15 º C +10 º C Air Ground Flat BAPV BIPV Source: Creep in Photovoltaic Modules: Examining the Stability of Polymeric Materials and Components (2010) 35 th IEEE Photovoltaic Specialists Conference (PVSC 10) Honolulu David C. Miller, Michael Krempe, Stephen Glick and Sarah Kurtz Viridian Solar January

12 Stress Intensity: Thermal Cycling Daily & Seasonal Temperature Fluctuations Stress PV Modules Partial Shading Can Cause Locally Elevated Temperatures (Hot Spots) Daily Cycling = C Seasonal Variation = ~30 C Source: easons/seasons.html Source: PV modules experience thousands of thermal cycles over their expected 20+ year lifetime Risk of partial shading is typically higher on rooftop projects, increasing the risk of diffused hot spot formation 87

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14 Defect Types and Occurrence Backsheets account for more than 40% of all the visual changes observed 89

15 Example of Defects Observed in the Field 4 Years of operation in Valencia, Spain. 2.3 MW field - estimated that approximately 5,000 modules in the park affected Some modules failed wet insulation test No loss of power to date 2 Year warranty on materials and workmanship had elapsed with no replacement of panels 90

16 Example of Defects Observed in the Field Very deep crack all the way through the depth of the backsheet. Solder ribbon and metallization visible. PET-based backsheet 4 years of operation in Valencia, Spain Module taken out of operation 91

17 Example of Defects Observed in the Field Frontside yellowing 4 Different countries (Belgium, Spain, USA and Germany) 50% of occurrence Modules less than 5 years in the field 5 Different manufacturers 92

18 Example of Defects Observed in the Field Yellowing, Cracking and Burned 3-Year old system (Spain) Module removed from service Cracking & Yellowing Hot spot caused backsheet to burn Areas around high temperature regions or hot spots may predict how materials will age 93

19 Example of Defects Observed in the Field 10-Year old module DuPont Tedlar film-based backsheet 10-Year old module PET-based backsheet 94

20 Backsheets can Impact Long-Term Power Performance 9% Power loss per year Backsheet Impact First US utility scale 1984 Sacramento, CA DuPont Tedlar - based backsheet DuPont Solamet metallization <0.9%/Yr Power Loss for 30 years 0% PET-based Tedlar -based 5-14 years years BoM can significantly impact the long-term power output of the PV module, affecting both the LCOE and the IRR Source: Joint Research Centre (Italy); AIST (Japan) 95

21 Powering Reliably Since 1982 University of Applied Sciences and Arts of Southern Switzerland (SUPSI) First grid-connected system in Europe (Switzerland) 10 kw rooftop system DuPont Tedlar film-based backsheet Low 0.4% annualized power loss after 31 years of service 96

22 Tedlar Protecting Rooftops for More Than 30 Years Installed in 1983 Nara, Japan Source: DuPont Photo courtesy of Sharp Corporation 97

23 Summary Think in terms of /kwh instead of /W p High efficiency modules can reduce system costs especially on rooftops Rooftops induce high thermal stress Ground mounts induce UV / thermal stress Know what s in your module Select backsheets with demonstrated track record in the field Work with well-established industry leaders up and down the value chain. (Picture of rooftop) 98

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