Long‐term performance degradation of various kinds of photovoltaic modules under moderate climatic conditions

Abstract

Various kinds of photovoltaic (PV) modules have been developed and practically operated as PV systems up to present. Investigation of the long‐term reliability of PV modules is indispensable for the use of PV systems as reliable energy sources. In this study, we show the results of outdoor exposure test in which the performance of 14 PV modules composed of five different kinds made by six different PV manufacturers have been measured since July 2004. The average performance is calculated in each year from 2005 to 2008, and the performance degradation is quantitatively evaluated. The results are that the magnitude of the performance degradation can be clearly classified by the kinds of the PV modules. The performance difference of the single‐crystalline silicon (sc‐Si) modules between 2005 and 2008 is from 1.9% to 2.8%. Polycrystalline silicon (pc‐Si) modules show performance degradation from 0.7% to 1.4%. The performance of an amorphous silicon/crystalline silicon (a‐Si:H/c‐Si) decreased by 0.7%. Although a pair of a‐Si modules had been already exposed to sunlight for about 6 months, the pair of modules show 4.4% of performance degradation. More than half of the performance degradation happened during the initial period from 2005 to 2006. This indicates that it takes about 2 years until the performance of a‐Si modules is stable. The performance is quite stable after 2006. Interestingly, the performance of the cupper indium gallium diselenide modules in 2008 is about 0.8% higher than that in 2005. Copyright © 2010 John Wiley & Sons, Ltd.

Performance Analysis of a Grid-Connected Upgraded Metallurgical Grade Silicon Photovoltaic System

“…Figure 2 also shows that PR was more variable under cloudy conditions where solar irradiation largely fluctuated. This confirms that wide fluctuation in irradiation can considerably reduce the precision of PR [15]. Thus, it is necessary to discard data points with large fluctuation in irradiation to obtain more reliable PV performance metrics.…”

“…Energies 2016, 9, 342 9 of 15 Investigation of daily and monthly PV performance shows that outliers due to snowing, shading, system down-time, data availability, and measurement errors complicate performance metrics, making PR inefficiently reflect the response of the PV array to irradiation.…”

Optimisation Principles for Photovoltaic/Thermal Hybrid Solar Systems, a Meta Study

“…[3,8] This truth in application has led to some research looking into hydrogenated amorphous Silicon (aSi:H) being used for the PV components as opposed to traditional mono or polycrystalline Silicon (c-Si), as the temperature coefficient for a-Si:H is typically 0.01% per Kelvin [5] compared to the c-Si value of 0.04% per Kelvin. [1][2][3][4][5][6][7][8][9][10] This is also due to the fact that a-Si:H can operate at a higher temperature, allowing the thermal working fluid to be raised to a higher temperature as well since the Second law of Thermodynamics dictates that heat can only go from a hotter body to a colder one. [5] High temperature conditions also cause accelerated degradation of the photovoltaic system through the means of thermally activated degradation processes, which include polymer degradation and collector contact corrosion.…”

“…It is this electron liberation process that is used as electrical energy in all solar powered systems, by creating metal contacts between negative (electron donor) and positive (electron acceptor) type semiconductors to create a circuit. [1][2][3][4][5][6][7][8][9][10][11] Conversely, light that does not have sufficient energy does not interact with the PV component, passing it and thus being collected by the thermal backplate. The backplate also collects radiative heat from the thermal relaxation of promoted electrons that absorbed photons of light larger than Eg that are preparing to recombine in the PV component of the system.…”

“…Not only does this collection method increase the spectral efficiency of the collection system as a whole [1][2][3][4][5][6][7][8][9][10][11], but the thermal component by nature acts as a heatsink for the photovoltaic component. This allows PVT systems to double down on efficiency gains, as higher thermal output means lower PV operation temperatures, which increase PV collection efficiency as well.…”