The Importance of Backsheets When Choosing Panels

q  This webinar will be available afterwards at www.solarpowerworldonline.com & email

q  Q&A at the end of the presentation q  Hashtag for this webinar: #SolarWebinar

Before We Start

Kelly Pickerel Solar Power World

Moderator Presenter

Lee Smith Dunmore

Installation Stress

•  Physically getting modules on roof •  Sharp corners •  Not getting shocked

Installation-challenges

Installation-challenges

Installation-challenges

Installation-challenges

Overview

•  What is backsheet? •  Backsheet failures •  The failure rate for solar modules •  Module types

–  Crystalline –  Thin film

•  Warranties •  Who is responsible if the module fails?

What is Backsheet The outermost back layer. What does it do? •  Makes the module light. •  Protects the installer. •  Keeps the adhesive from •  yellowing. •  Reflects to increase

energy.

TEXTBOOK REFLECTION OF LIGHT OFF BACKSHEET TO FRONT GLASS TO CELL

Handbook of Photovoltaic Science and Engineering

Typical Backsheet Construction

PV Module Stresses Protection from:

●  UV- Rays

●  Temperature changing

○  - 40°F to 185°F

●  Humidity and vapor

●  Dryness / wind / dust / sand

●  Scratches during installation and maintenance

●  Electrical insulation

Internal Testing •  Damp Heat Test (external TUV 85°C and 85% r.h.) •  Damp Heat Test (internal 85°C and 85% r.h.) •  Partial Discharge Test at TUV and VDE •  Turbo Damp Heat Test (120°C and 100% r.h.) •  Peel Test 90° (internal method) •  UV-Test (IEC 61215) •  Shrinkage Test (150°C and 30 min) •  Water Vapor Barrier Test •  Special UV-Test at ISE Fraunhofer Institute Freiburg (IEC 61215) •  UV - Damp Heat Combination Test at ISE Fraunhofer Institute

UV - Damp Heat Combination Test

Climate chamber with UV light source - Fraunhofer

PV Backsheet Failure

Module Field Failure

Module Replacement Rates

How often can they fail? •  National Renewable Energy

Laboratory (NREL) –  2012 NREL Reliability

Workshop •  Workmanship Warranties

went from 2 to 10 years.

Crystalline Modules

•  Typical flat panel •  Rigid •  Oldest type •  Black or blue cells

When Thin is More •  Flexible PV modules

–  No need for mounting racks –  No roof penetration –  Higher surface area

•  Ideal applications –  Light weight roofs –  High wind areas –  Curved surfaces –  Flat roof applications

Image credit: Global Solar

Warranty •  Can be confusing

–  Power Purchase Agreement (PPA) –  Lease agreement –  Engineering, Procurement & Construction (EPC)

agreement –  Operations & Maintenance agreement (O&M)

•  Crystal clear •  Failure is on your customer’s roof •  You’re going to be the first person they contact

Reputation

•  Reputation of the manufacturer •  Your reputation

Questions? Kelly Pickerel Solar Power World kpickerel@wtwhmedia.com Twitter: @solarkellyp

Lee Smith Dunmore lsmith@dunmore.com

q  This webinar will be available at www.solarpowerworldonline.com & email

q  Tweet with hashtag #SolarWebinar

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Thank You