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Title: Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint

Abstract

This paper describes a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1296611
Report Number(s):
NREL/CP-5D00-66498
DOE Contract Number:
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the 43rd IEEE Photovoltaic Specialists Conference, 5-10 June 2016, Portland, Oregon
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 47 OTHER INSTRUMENTATION; PV modules; degradation; calibration; field measurements

Citation Formats

Vignola, Frank, Peterson, Josh, Kessler, Rich, Mavromatakis, Fotis, Dooraghi, Mike, and Sengupta, Manajit. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint. United States: N. p., 2016. Web. doi:10.1109/PVSC.2016.7749764.
Vignola, Frank, Peterson, Josh, Kessler, Rich, Mavromatakis, Fotis, Dooraghi, Mike, & Sengupta, Manajit. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint. United States. doi:10.1109/PVSC.2016.7749764.
Vignola, Frank, Peterson, Josh, Kessler, Rich, Mavromatakis, Fotis, Dooraghi, Mike, and Sengupta, Manajit. Mon . "Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint". United States. doi:10.1109/PVSC.2016.7749764. https://www.osti.gov/servlets/purl/1296611.
@article{osti_1296611,
title = {Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint},
author = {Vignola, Frank and Peterson, Josh and Kessler, Rich and Mavromatakis, Fotis and Dooraghi, Mike and Sengupta, Manajit},
abstractNote = {This paper describes a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.},
doi = {10.1109/PVSC.2016.7749764},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}

Conference:
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  • This poster provides an overview of a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.
  • Methodology is described that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is discussed. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.
  • Photovoltaic (PV) module degradation rate analysis quantifies the loss of PV power output over time and is useful for estimating the impact of degradation on the cost of energy. An understanding of the degradation of all current-voltage (I-V) parameters helps to determine the cause of the degradation and also gives useful information for the design of the system. This study reports on data collected from 12 distinct mono- and poly-crystalline modules deployed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Most modules investigated showed < 0.5%/year decrease in maximum power due to short-circuit current decline.
  • To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this paper we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technologymore » and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.« less
  • The sheet resistance of three soil types (Arizona road dust, soot, and sea salt) on glass were measured by the transmission line method as a function of relative humidity (RH) between 39% and 95% at 60 degrees C. Sea salt yielded a 3.5 order of magnitude decrease in resistance on the glass surface when the RH was increased over this RH range. Arizona road dust showed reduced sheet resistance at lower RH, but with less humidity sensitivity over the range tested. The soot sample did not show significant resistivity change compared to the unsoiled control. Photovoltaic modules with sea saltmore » on their faces were step-stressed between 25% and 95% RH at 60 degrees C applying -1000 V bias to the active cell circuit. Leakage current from the cell circuit to ground ranged between two and ten times higher than that of the unsoiled controls. Degradation rate of modules with salt on the surface increased with increasing RH and time.« less