Analysis of twelve-month degradation in three polycrystalline photovoltaic modules

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


Polycrystalline silicon photovoltaic (PV) modules have the advantage of lower manufacturing cost as compared to their monocrystalline counterparts, but generally exhibit both lower initial module efficiencies and more significant early-stage efficiency degradation than do similar monocrystalline PV modules. For both technologies, noticeable deterioration in power conversion efficiency typically occurs over the first two years of usage. Estimating PV lifetime by examining the performance degradation behavior under given environmental conditions is, therefore, one of continual goals for experimental research and economic analysis. In the present work, accelerated lifecycle testing (ALT) on three polycrystalline PV technologies was performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability, providing an illumination uniformity of 98% over a 2 x 1.6m area. In order to investigate environmental aging effects, timedependent PV performance (I-V characteristic) was evaluated over a recurring, compressed day-night cycle, which simulated local daily solar insolation for the southwestern United States, followed by dark (night) periods. During a total test time of just under 4 months that corresponded to a year equivalent exposure on a fielded module, the temperature and humidity varied in ranges from 3°C to 40°C and 5% to 85% based on annual weather profiles for Tucson, AZ. Removing the temperature de-rating effect that was clearly seen in the data enabled the computation of normalized efficiency degradation with time and environmental exposure. Results confirm the impact of environmental conditions on the module long-Term performance. Overall, more than 2% efficiency degradation in the first year of usage was observed for all thee polycrystalline Si solar modules. The average 5-year degradation of each PV technology was estimated based on their determined degradation rates.

Original languageEnglish (US)
Title of host publicationReliability of Photovoltaic Cells, Modules, Components, and Systems IX
EditorsNeelkanth G. Dhere, John H. Wohlgemuth, Keiichiro Sakurai
ISBN (Electronic)9781510602670
StatePublished - 2016
EventReliability of Photovoltaic Cells, Modules, Components, and Systems IX - San Diego, United States
Duration: Aug 28 2016Aug 29 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherReliability of Photovoltaic Cells, Modules, Components, and Systems IX
Country/TerritoryUnited States
CitySan Diego


  • accelerated lifecycle testing
  • degradation
  • environmental chamber
  • photovoltaic
  • polycrystalline

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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