Accelerated Testing and Analysis
We subject photovoltaic (PV) components and materials to accelerated testing conditions to provide early indications of potential failures. The results are coupled with an understanding of environmental conditions to predict field performance and lifetime.
Tools and Capabilities
- Accelerated Testing of Modules
To conduct accelerated testing of modules, NREL maintains and operates a collection of environmental chambers (see Indoor Testing) for applying humidity, heat, electrical bias, white light, and ultraviolet (UV) light. The chambers accommodate modules of variable sizes. We use of these chambers to develop new tests that quantitatively correlate with field failure rates.
- Accelerated Testing of Components and Materials
NREL maintains and operates hardware for testing small components and materials. We can apply up to about 40 suns of UV intensity while controlling the temperature and humidity and up to about 1,000 suns of UV in an uncontrolled environment. Rapid thermal cycling of small components with variable electrical bias is also available.
These activities are funded by the Department of Energy's Office of Energy Efficiency and Renewable Energy:
International PV Module Quality Assurance Task Force (PVQAT)
This effort also supports other SuNLaMP, PREDICTS, and PVRD projects. This work is closely coordinated with the work of PVQAT and the International Electrotechnical Commission to hasten the development and adoption of international standards.
Standards Development for Photovoltaic Reliability
In collaboration with PVQAT, NREL is supporting the development of comprehensive standards for PV reliability using a three-pronged strategy focused on:
- Establishing qualification methods for durability of PV module design with a chosen climate and mounting system
- Developing a guide for auditing quality management systems toward consistent manufacturing of PV modules built to that design
- Ensuring adequacy of design, installation, and operation through a certification process for system verification.
As a near-term aid in improving PV reliability, NREL has developed the Qualification Plus Testing method. The elements of Qualification Plus are being implemented in international standards.
Laboratory personnel participate in writing and discussing reliability, safety, and test and evaluation standards—primarily with International Electrotechnical CommissionTechnical Committee 82 (Working Groups 2, 3, 6, and 7), but also with a number of other standards organizations including the American Society for Testing and Materials, Underwriters Laboratories, and TUV Rheinland. This work is done in partnership with Solar ABCs. NREL researchers work through PVQAT to effectively leverage the knowledge of the broader PV community toward developing comprehensive PV standards.
Each year, our researchers, along with solar companies and other national lab researchers, participate in an industry workshop on PV reliability, conducted to encourage exchange of information about PV reliability. Proceedings of past workshops are available.
NREL publishes PV reliability journal articles, technical reports, conference papers, and outreach documents.
Nick Bosco: Thermal and mechanical fatigue, measurement of adhesion
Peter Hacke: Potential-induced degradation, accelerated lifetime testing and modeling
Mike Kempe: Weathering of polymeric materials
David Miller: Weathering and characterization of PV packaging materials
Ingrid Repins: CIGS reliability
Timothy Silverman: Modeling and testing of the effects of partial shade