Know What is in Your Module Materials Matter Stephan Padlewski, Marketing Manager, EMEA DuPont Photovoltaic Solutions, Geneva, Switzerland

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1 Know What is in Your Module Materials Matter Stephan Padlewski, Marketing Manager, EMEA DuPont Photovoltaic Solutions, Geneva, Switzerland

2 We are Applying our Science to Find Solutions to Some Really BIG Challenges FEEDING THE WORLD National Geographic images REDUCING OUR DEPENDENCE ON FOSSIL FUELS KEEPING PEOPLE AND THE ENVIRONMENT SAFE

3 DuPont Offers the Broadest Materials Portfolio in the PV Industry Cell Materials Module Materials BoS Materials Solamet metallizations Innovalight silicon inks Kapton substrates Niapure sodium metal Tedlar PVF backsheet films Elvax Ionomer PVB encapsulants Teflon frontsheets Rynite Zytel resins Kalrez Zalak parts & seals Vespel parts Kapton photo courtesy of Solarion AG

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

5 Warranties and Bankability Status Are No Longer Effective in Mitigating Risk Example 1 42 kw ground array; c-si modules 4 years old at time of discovery Installation error Backsheet puncture Frontside cell and metallization corrosion Form factor no longer available no recourse Example 2 40 kw roof array; c-si modules 4 years old at time of discovery Shattered glass 3% of modules Mechanical stress from installation Interconnect breakage Cannibalized array Finger pointing installer and module maker Module maker subsequently out of business 6 months downtime

6 Know what is in your Module Materials Matter Unproven and inferior materials are being substituted in modules threatening durability and lifetime

7 LCOE - The Better Measure of Overall Cost of Ownership IRR System Revenue PV LCOE System Cost Lifetime Power Output Modules BoS O&M Financing System Efficiency System Life Insolation Annual Degradation Shading Low-light Performance Component Failures

8 DuPont PV Materials Impact Three Critical Areas Essential to Lowering LCOE 1. Efficiency 2. Lifetime 3. BoS Cost Industry roadmap to 20+% c-si cells, enabled by new materials Robust materials enabling >30 year module lifetimes with high performance Lower cost, lightweight polymers to replace glass and metals Drive lower PV LCOE to achieve grid parity and higher returns

9 Mono c-si Cell Conversion Efficiency (%) Higher Efficiency Reduces Total Cost and Improves Performance Metallization Enables Accelerating Improvements through 2015 Cell Efficiency Evolution (State-of-the-Art Production) Back Contact Solamet PV70x New LBSF (LDE) Architectures Solamet PV36x High Efficiency LDE Cells Solamet PV17x, 18x High Efficiency Cells Solamet PV15x, 16x Conventional Cells Solamet PV14x Products +1.5% +2.65% Source: DuPont

10 Lower Power Degradation Means Higher Returns 30 Years 25 Years 35 Years 20 Years Modules that can improve expected power output and lifetime. Premium cost can translate into lower LCOE and higher IRR. 10

11 Backsheet Failure Can Result in Power Loss, Investment Loss and Even Bodily Harm Broken Interconnects Encapsulant Discoloration Frontside Glass Delamination Cell Hot Spots Backsheet Delamination Broken Cells Cell corrosion Structural Failure of Module Frame Cell Corrosion due to Backsheet Failure Catastrophic Power Loss (Reliability) Source: NREL, DuPont Accelerated Power Loss (Durability) 11 Safety Failure/ Risk

12 Power Output Power Output Backsheet Performance is Critical to Reliable, Durable and Safe Module Operation Backsheet Failure Module Failure Potential Impact Delamination from EVA or J-box Reliability Lost revenue Interlayer delamination Time Durability Brand and reputation damage Cracking & Tearing Warranty claims Discoloration Time Safety Lower financial returns Loss of insulation Bodily harm 12

13 Materials Cost Impact on PV Cells & Modules Bill of Materials Gasket/Edge Seal (4%) 0.7 Packaging (2%) Other Materials (3%) Junction Box (5%) Cost of Materials in US$/W Other Mat ls (11%) Junction Box (3%) Encapsulant (7%) Backsheet (10%) Front Glass (10%) Metal Paste (17%) Encapsulant (5%) Gases (6%) Targets (7%) Module Frame (13%) Backsheet (18%) Silicon Metal (42%) TCO Front Glass (36%) 0 Crystalline Silicon Thin Film Backsheet represents a tiny portion of the total cost. But it plays a critical role in module durability & reliability. Source: DuPont

14 Lifetime: Accelerated vs. Field Testing IEC testing protocols do not adequately simulate field stress environment Qualification Tests 1 to 2 stresses in series 15 kwh per m2 of UV radiation 200 thermal cycles No solar load (not in operation) in testing chambers 25 Years In-Field Multiple environmental and mechanical stresses 1.5 MWh of UV radiation* 1000s of thermal cycles 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 Field-aged Crystalline Silicon Photovoltaic Modules, Wiley InterScience, 2008

15 Solar Irradiation Map for South Africa PVGIS European Communities, ; 2012

16 Recommended UV Exposures Based on Climate DuPont Desert Tropical Temperate Annual UV (kwh/m2) (source Atlas) year UV Exposure to Back of albedo (kwh/m 2 ) IEC UVA Exposure Level to Simulate 25 years (hrs)* 15kWh/m2 pre-conditioning can lead to no exposure of backsheet DuPont recommended dose of 171 to 275 kwh/m2 matches real world conditions 12% albedo estimated from literature sources and DuPont field data (1) *UVA: 70 C, BPT 340nm, (65 W/m², nm), continuous, no condensation (1) R. Chadysiene and A. Girgzdys, Ultraviolet Radiation Albedo of Natural Surfaces, J. Env, Eng. Land. Mgmnt,, 16(2): (2008)

17 17 Analysis on JRC and AIST Fielded Modules Time in Backsheet Number of Study Service Construction Modules (years) JRC Glass JRC Tedlar AIST PET Based AIST PVF/PET/PVF In two separate studies, modules containing Tedlar based backsheets showed lower power loss and less variability than modules using glass or PET based backsheets.

18 Spain (Valencia), Roof Mounted, 4 Years Module 3 Backsheet yellowing on the EVA side of the backsheet 100% occurrence in the park Module 3 Solder ribbon blackening (does not look like corrosion) 100% occurrence in the park Outer backsheet: Polyvinyl difluoride (PVDF) Module 3 Washed off labels 100% occurrence in the park

19 Spain (Valencia), Ground Mounted, 4 Years Module 4 - type B Cracked backsheet Safety concern All of the type B modules affected Outer backsheet: Polyester (PET) Module 4 - type A Snail trails Frequent occurrence, ca. 30% (No stats performed) Outer backsheet: Unknown

20 Some Photos of Modules Sent to DuPont Module A Deep cracks Hot spot leading to yellowing and delamination Module B Backsheet flaking off Yellowing and cohesive delamination in hot spot areas Outer backsheets: PET Module C Slight backsheet yellowing on air side

21 What Can You Do Today Four Ways to Mitigate Your Risk 1.Think in terms of LCOE 2.Ensure your system utilizes proven bill of materials, system design and manufacturing practices. 3.Know what materials are in your module because all modules are not created equal. 4.Work with well-established industry leaders up and down the value chain who will prevail long-term.

22 Back-Up

23 Backsheet Accelerated Stress Test Results Using DuPont Lab Tests PVF PVF PA PET PET PET PA PET Conditions Impact PVF Tie Layer PA Tie Layer UV Exposure Humidity Exposure Thermal Cycling Yellowing Cracking Tearing Delamination Corrosion Yellowing Cracking Tearing Years in the field Tedlar (PVF film) based backsheets demonstrate the best balance of properties across all tests required for long module lifetime.

24 In Addition to Field Performance, Testing can be Used to Help Make the Right Backsheet Choice Backsheet Requirements Ultra Violet (UV) Transmitted Reflected Temperature Peak Cycling Moisture Humidity Precipitation Condensation Corrosive Environment Atmospheric chemicals Ammonia Marine environment Electrical Insulation Shock Shorting Physical Protection Abrasion Impact Performance Evaluation 1. Reliability tests Originally developed based on Jet Propulsion Laboratory (JPL) study design Apply selectively to evaluate backsheet properties Unknown correlation with field performance Accelerated tests may produce failures not seen in the field 2. IEC Qualification Tests Not designed, nor sufficient to predict long-term performance 3. Field performance Best indicator of long-term performance Long duration needed 24

25 Global Scope of DuPont Science & Technology >9,500 Scientists and Engineers $2.1 Billion R&D Spend in 2012 Over 150 R&D Centers Worldwide EUROPE Neu Isenberg, Germany Geneva, Switzerland Bristol, UK Luxembourg Russia Turkey NORTH AMERICA Wilmington, DE Manati, Puerto Rico Parlin NJ Circleville, OH Fayetteville, NC Louisville, KY Bayport, TX Towanda, PA Research Triangle Park, NC Santa Barbara, CA Logan, UT Hayward, CA Tempe, AZ Fort Madison, IA Dayton, OH LATIN AMERICA Alphaville, Brazil Buenos Aires, Argentina Mexico Bogotà, Colombia ASIA PACIFIC Taoyuan, Taiwan Dongguan, PRC Gurgaon, India Hong Kong Tokai, Japan Tokyo, Japan Shanghai, China Shenzen, China Hsinchu, Taiwan Seoul, Korea Presence close to markets to meet customer needs