1. Proven Power and Lasting Value
DuPont Photovoltaic Solutions
Materials Matter™ for PV Module Quality and Effective Risk Management
5th EQ Solar & Wind Power Investment and Tech Summit
22 February 2017, Mumbai
Rahul Khatri
Technical Manager, India
DuPont Photovoltaic Solutions
Photovoltaic Solutions

2. Current Risk Mitigation Methods Are Not Effective
Will Your Modules Perform for 25 Years in the Field?
Assumptions
Annual Power Degradation: 0.7% / year
Risk Mitigation Methods
Warranties
IEC Certification
Tier 1
Module manufacturer insolvency
Claim settlement can take 4 – 6 months
Not a lifetime test
Many instances of failures of IEC tested modules
Ranking is not based on module quality
Current Risk Mitigation Methods Are Not Effective 2

3. Materials Impact Module Performance in the Field
3rd Party Studies: An Increasing Trend in Module Defects
PV module defects increased from 19% in 2013 to 48% in 2015, according to research conducted by TUV1
In addition to potential induced degradation (PID) and glass breakage, defective backsheets are contributing to serious defects of solar modules
Materials Impact Module Performance in the Field .
1 TUV Rheinland Intersolar 2015, Roundtable Solarpraxis 3

4. Consequences of Compromising on Module Quality…
Early Signs of Backsheet Failure
Backsheet Type: PET Based
4 years old plant in North China
Significant yellowing of backsheet (b* = 8-10)
Bubbling and Delamination
Yellowing is a Visible Sign of Material Degradation (Brittleness) and Can Lead to Cracking

5. Backsheet Degradation Can Lead to Catastrophic Failures
Backsheet Type: PET
5 years old installation in Spain
Yellowing and Cracking
32% power loss over 5 years (6.4%/year)
Some modules failed wet leakage test – Safety Risks
Backsheet Type: PVDF
4 years old installation in North America
Severe cracking and delamination of PVDF film
57% of the installed modules impacted
Backsheet Type: PET
9 years old installation in West China
Severe cracking, peeling and yellowing
Backsheet Type: Polyamide (PA)
5 years old installation in Italy
Severe cracking and delamination of PA film
Inverter tripped due to current leakage

6. Unproven Materials Increases Risk of Module Failure
Case Study: Polyamide Based Back-sheets
History
Introduced about 6 years ago as a low cost alternative
Passed all IEC and internal tests
Many manufacturers started using it due to lower cost
Current Scenario
Multiple cases of backsheet cracking after 3-4 years in the field
Generation losses due to inverter tripping in some cases
5-7 GW of currently installed systems with Polyamide based backsheets are at significant risk
Spain - 4 years old, 2.3 MW field, based on 2 module types
China - 4 years old,
large cracks
Italy – large crack
tripped inverter
Root Cause
Unproven materials increases risk of module failure
Existing tests standards are ineffective to predict field performance
Unproven Materials Increases Risk of Module Failure 6

7. Alleviating Module Risks Requires Focus on:
Use Proven Bill of Material
Adopt Test Methods That Better Simulates Field Ageing Mechanisms
Crystalline Silicone PV Module Structure
Damp Heat UV
Thermal Cycling 7

8. Specify Use of Proven BoM for PV Modules
Proven Bill of Materials
11 – 27 years old installation in China
<0.8% power annual power loss
All modules have Tedlar® PVF film-based backsheets
Specify Use of Proven BoM for PV Modules 8

9. Key Learning Focus on quality for healthy financial returns
Module Bill of Materials (BoM) is extremely critical for module reliability and durability
Focus on using proven BoM to mitigate failure risks
Share to help industry learn & grow

10. When Materials Matter™, go with the proven leader
When Materials Matter™, go with the proven leader. What you’ll get is proven power and lasting value you can count on for the long term, for greater peace of mind.
DuPont Photovoltaic Solutions
Day After Day
Since presenting our first technical paper on the use of Tedlar® PVF film in PV applications nearly 50 years ago, we have become the leading PV material expert.
Today, our capabilities extend from materials to modules, including fundamental PV materials science and cell and module processing, architecture and testing.
We are also a PV system owner and PV electricity user, with PV systems at DuPont sites around the world. As we look to the future, our commitment only grows.
You can count on our materials to deliver proven power and lasting value because of our deep commitment to four areas:
 LIFETIME PERFORMANCE
DuPontTM Tedlar® is the long-standing benchmark for the industry. Newer materials have since emerged, but none demonstrate the durability and longevity Tedlar® has over its more-than-30-year history in the field. As the industry seeks to maximize returns by extending system lifetimes, Tedlar® continues to be the clear choice for backsheets.
LIFETIME EFFICIENCY
DuPontTM Solamet® continues to set new standards for efficiency. Solamet® is the first choice for customers who seek to continually improve solar cell and panel efficiencies, to ultimately reduce LCOE.
FINANCIAL RETURNS
We focus on not only delivering higher power output over the course of a lifetime, but also greater safety, peace-of-mind and lower risk, which add up to lifetime returns that are both higher and more predictable.
FIELD-TESTING
Recent history has shown there is no substitute for field-testing, and no one else even comes close to us in this area. We have vigorously evaluated our field-proven materials in extreme environments for over 30 years, and we continue to do so today.
photovoltaics.dupont.com
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11. + + Financial Returns Depend on Multiple Factors
Financial Performance
[Return on Investment]
Energy Produced
Output & Safety Performance (kWh)
Cost of Capital
External Factors + +
Reliable PPA
Module Reliability
Module
System Uptime
Inverters & BoS
Risks
Operation & Maintenance
Finance
Insurance
A mature market would improve financial performance by optimizing energy generation and reducing risks (cost of finance and insurance) through use of high quality modules and incorporating robust installation and maintenance practices. In India, the focus is more on reducing the cost of capital primarily by using cheap modules which increases risks on module performance and thus attracts higher finance and insurance cost. Moreover, this puts India’s solar mission in danger as a few large scale failures would be sufficient to dampen the interests of financers without whom the industry cannot progress
Weather
Focus on Optimizing Energy Generation for Better Returns