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A Giant Leap Forward toward Quality 

Assurance of PV Modules

2012 PV Module Reliability Workshop

Golden, CO

Sarah Kurtz1, John Wohlgemuth1

, 

Tony Sample2

, Masaaki Yamamichi3

1NREL

2EC-JRC

3AIST

Feb. 29, 2012

NREL/PR-5200-54567
 NATIONAL RENEWABLE ENERGY LABORATORY

Outline

• Motivation – Customers want to know quality 

of PV modules

• Two parts of quality assurance (QA) (during 

design and manufacturing phases)

• QA Task Force – formed July, 2011

• Plan for today:

• Review IEC 61215 as a starting point

• Review proposed new tests

• Task Groups 2-5: introduction and updates

• Discussions: consensus building; identification of issues

2
 NATIONAL RENEWABLE ENERGY LABORATORY

Motivation: the question on the street 

“How do I predict lifetime of PV modules?”

• Reliability engineer: How do I test to determine 

the number of years for the warranty?

• PV customer: How do I choose the PV module 

that will last longer?

• PV investor: How do I know that I’m making a 

safe investment of $1 billion (if the modules fail 

after 10 yr, the warranty will be worthless 

because the company will be gone)?

• Insurance company: How do I determine rates 

for insuring PV installations?

• PV Manufacturer: How do I differentiate my 

product from other products?

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 NATIONAL RENEWABLE ENERGY LABORATORY

1. Is the design durable for the intended application?

– Depends on location (hot & humid; hot & dry, temperate, 

etc.)

– Depends on mounting (close-roof mount runs hotter; partially 

shaded modules undergo different types of stress)

– Depends on application (a customer may plan to resurface 

the roof 10 years from now and only cares about the 

modules lasting that long)

2. Are the modules consistently manufactured?

– Could variations in the material composition or 

manufacturing processes result in premature failure of some 

fraction of the modules?

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Two parts of Quality Assurance
 NATIONAL RENEWABLE ENERGY LABORATORY

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International PV Module Quality Assurance Forum

was held in July, 2011, San Francisco

General agreement to work together on PV QA

Formed International PV QA Task Force:

Group of volunteers/professionals working toward a 

common goal 
 NATIONAL RENEWABLE ENERGY LABORATORY

The PV QA Task Force formed at the conclusion of the Forum 

consists of six Task Groups:

Task Group 1: PV QA Guideline for Manufacturing Consistency 

(leaders Ivan Sinicco, Alex Mikonowicz, Yoshihito Eguchi, Wei 

Zhou, G. Breggemann)

Task Group 2: PV QA Testing for Thermal and mechanical fatigue including

 vibration (leader Chris Flueckiger, Tadanori Tanahashi)

Task Group 3: PV QA Testing for Humidity, temperature, and voltage

 (leaders John Wohlgemuth, Neelkanth Dhere, Takuya Doi)

Task Group 4: PV QA Testing for Diodes, shading and reverse bias

 (leaders Vivek Gade, Paul Robusto, Yasunori Uchida)

Task Group 5: PV QA Testing for UV, temperature and humidity 

 (leader Michael Köhl, Kusato Hirota, Jasbir Bath)

Task Group 6: Communication of PV QA ratings to the community 

 (leader David Williams)

140 volunteers; held meeting last night

230 volunteers for Task Groups 2-6
 NATIONAL RENEWABLE ENERGY LABORATORY

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International PV Module Quality Assurance Forum

July, 2011, San Francisco 

Formed International PV QA Task Force: 

Goals of International PV QA Task Force: 

1. To develop a QA rating system that provides comparative 

information about the relative durability of PV modules to a 

variety of stresses as a useful tool to PV customers and as a 

starting point for improving the accuracy of quantitative PV 

lifetime predictions.

1) Compare module designs

2) Provide a basis for manufacturers’ warranties 

3) Provide investors with confidence in their investments

4) Provide data for setting insurance rates

2. Create a guideline for factory inspections of the QA system used 

during manufacturing.
 NATIONAL RENEWABLE ENERGY LABORATORY

8

International PV Module Quality Assurance Forum

July, 2011, San Francisco 

Formed International PV QA Task Force: 

Goals of International PV QA Task Force: 

1. To develop a QA rating system that provides comparative

information about the relative durability of PV modules to a 

variety of stresses as a useful tool to PV customers and as a 

starting point for improving the accuracy of quantitative PV 

lifetime predictions.

1) Compare module designs

2) Provide a basis for manufacturers’ warranties 

3) Provide investors with confidence in their investments

4) Provide data for setting insurance rates

2. Create a guideline for factory inspections of the QA system used 

during manufacturing.
 NATIONAL RENEWABLE ENERGY LABORATORY

Task Group 1: PV QA Guideline for Manufacturing Consistency 

 met last night (Feb. 28th):

• The regional task groups are each working on a PV-specific version 

of ISO 9001:2008

• This will define an ISO 9001-like quality management system with 

technical specifics relevant to PV: e.g., documentation of control of 

solder-bond quality

• The procedure for turning this ISO-like document into a standard is 

not yet clear, but is being investigated; may involve ISO and/or IEC

• Chinese regional group is planning to complete their draft by the end 

of March

• It is currently envisioned that this certification would be a way to 

differentiate products, not be required for a baseline IEC 61215 

certification. For example, an insurance company might reduce the 

rate based on adding the PV-specific ISO 9001-like certification 
 NATIONAL RENEWABLE ENERGY LABORATORY

Introduction to Today – What can we accomplish 

today?

Challenge is to accomplish our goals quickly

- Many ideas

- Not enough experience/wisdom for the path to be clear

- We will need to work together effectively and pool the 

wisdom we do have!

- Move decisively on the information we have

- Plan to modify approach as more information becomes 

available
 NATIONAL RENEWABLE ENERGY LABORATORY

1. Current status: IEC 61215 – what it does and doesn’t do

2. Overview of many test methods that are out there

– IEC 61215 on steroids; Accelerated simulation of weather; New 

tests

– Beware: Many details lead to much confusion

– Listen: What makes each test method valuable?

3. Overview of status of the QA Task Groups 2-5

– Listen: What are the questions that need to be resolved?

Lunch

4. Community input/discussion

1. Discuss the value we found in the proposed tests – see hand out

2. Consensus building – what can we agree about? – see hand out

3. Your concerns/questions

4. Next steps

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Introduction to Today
 NATIONAL RENEWABLE ENERGY LABORATORY

• Customer’s perspective

• #1 desire: A number that indicates the service life (would this be 

meaningful?)

• Relevant to customers’ application

• Easy to understand, but sophisticated customers would like 

detail

• Tests that do not add to the cost

• Manufacturer’s perspective

• Single set of tests (applied under ILAC: International Laboratory 

Accreditation Cooperation)

• Tests that require minimal time and minimal expense

• Ability to differentiate products

• Scientific perspective

• Must be meaningful (based on data, not guesses)

• Logical approach may be helpful

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Requirements for a comparative QA rating 

system

Today we are limited to a comparative test, but we want to lay the 

groundwork for quantitative predictions in the future
 NATIONAL RENEWABLE ENERGY LABORATORY

- Keep your eye on the goal – inexpensive, comparative 

standards that correlate with field performance 

- Look amongst us for wisdom of what is most useful to 

the community, setting aside personal agendas

- Take a giant leap forward toward creating comparative 

test standards that go “beyond” IEC 61215

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My requests to you for today and going forward: