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Temporal Change in the Power Production of Real-world Photovoltaic Systems Under Diverse Climatic Conditions

Hu, Yang
http://orcid.org/0000-0002-4734-4439
http://rave.ohiolink.edu/etdc/view?acc_num=case1481295879868785

Abstract Details

2017, Doctor of Philosophy, Case Western Reserve University, Materials Science and Engineering.
Over 1000 photovaltaic (PV) systems' lifetime performance changes under real-world operation conditions were studied in pursuit of a better understanding of the impact of external variables on the durability of PV systems. These PV systems are part of the SDLE Research Center's global sunfarm network (GSFN), which has developed to include 787 PV power plants and outdoor test facilities. The analysis of this large PV data set was driven by a non-relational data warehouse for multiple heterogeneous energy data, referred to as Energy-CRADLE. The rate of power change was calculated using a month-by-month approach, explicitly, a linear regression model (the ß model) was fitted to each 30 day increment of data to train a predictive model for the output power of PV systems. The system's power output was then predicted under a selected environmental condition for each 30 day segment. A second linear or piecewise linear regression model (the ¿ model) was fitted to the monthly predicted power output values, with a weight on the inverse of the error of the prediction. For 655 PV systems where the monthly predicted values were well explained by a linear model, the annual rate of change were calculated from the slope of the linear regression fitting. These 655 systems were between two and eight years old, they were distributed in 9 different climate zones according to Koppen-Geiger Climate classification, the PV modules being used were from 20 different PV manufacturers, and the inverters being used were from 9 different manufacturers. A third multiple regression model (the ¿ model) was fitted to the 655 rate of change results. The variables being considered in the third model exhausted all external variables of the PV systems. Through a statistical variable selection method, stepwise Akaike information criterion (AIC), the variables that had statistically significant influence on the system change rate were selected and rank ordered by their contribution follows: Koppen-Geiger climate zones , PV module manufacturer, system age (in months), and the mounting method (roof, ground, and canopy) of the system. From the piecewise fitting of the predicted power output, two competing phenomena were observed, one was an initial performance increase that appeared over a timespan of several months to over a year, the other was the performance degradation that lasted over the system's lifetime. As a result of these two competing phenomena, a PV system's performance exhibits change point behavior, experiencing an initial increase in power at the beginning of its service life, and eventually change to power loss (power degradation) over time.
Roger French (Advisor)
Timothy Peshek (Committee Member)
David Matthiesen (Committee Member)
Mehmet Koyuturk (Committee Member)
157 p.
Energy; Engineering
Photovoltaics, Power change rate, Real-world PV systems, Koppen-Geiger Climate Zone classification, linear regression, data science, non-relational data warehouse, non-linear degradation

Recommended Citations

Citations

  • Hu, Y. (2017). Temporal Change in the Power Production of Real-world Photovoltaic Systems Under Diverse Climatic Conditions [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1481295879868785

    APA Style (7th edition)

  • Hu, Yang. Temporal Change in the Power Production of Real-world Photovoltaic Systems Under Diverse Climatic Conditions. 2017. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1481295879868785.

    MLA Style (8th edition)

  • Hu, Yang. "Temporal Change in the Power Production of Real-world Photovoltaic Systems Under Diverse Climatic Conditions." Doctoral dissertation, Case Western Reserve University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1481295879868785

    Chicago Manual of Style (17th edition)

case1481295879868785
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© 2016, some rights reserved.Creative Commons License Temporal Change in the Power Production of Real-world Photovoltaic Systems Under Diverse Climatic Conditions by Yang Hu is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.
Release 3.2.12