In October of 2013, Suncore's 50MW solar power plant in Golmud, Anhui, China became fully operational. Performance parameter extraction for Suncore's 1090X DDM module, based on the Photovoltaic Array Performance Model developed at Sandia National Labs, will be presented. These extracted parameters, along with solar resource and environmental data from the site, were used to predict the energy production of the plant prior to installation. The measured solar resource and environmental conditions at the site will be compared to the typical data used for the energy production estimates. In addition, the predicted energy production will be compared to actual production of the field. The achieved derates will be compared to the upfront prediction of these losses.

EMCORE's Concentrator Photovoltaic (CPV) systems use large-format Fresnel lenses to achieve 1090X concentration onto high-efficiency multi-junction solar cells. The use of Fresnel lenses is common in CPV systems due to their thin profile and light weight. EMCORE uses silicone-on-glass (SOG) lens technology, which provides a high-reliability, high-durability alternative to acrylic lenses. This paper describes performance variations of these lenses based on the Fresnel groove depth. Both the optical efficiency and temperature dependence of the optical system are evaluated as a function of groove depth.

Four approaches to modeling multi‐junction concentrating photovoltaic system performance are assessed by comparing modeled performance to measured performance. Measured weather, irradiance, and system performance data were collected on two systems over a one month period. Residual analysis is used to assess the models and to identify opportunities for model improvement.

As photovoltaic systems become larger and more numerous, improved methods are needed for testing and modeling their performance. Test methods that successfully separate the interacting, time-of-day dependent influences of solar irradiance, operating temperature, solar spectrum, and solar angle-of-incidence have now been developed. These test methods have resulted in a new array performance model that is reasonably simple, yet accurately predicts performance for all operating conditions. This paper describes the new model, outdoor tests required to implement it, results of field tests for five arrays of different technologies, and the evolution of the model into a numerical tool for designing and sizing photovoltaic arrays based on annual energy production.

Improvements in the methods used for photovoltaic (PV) system design, performance rating, and long-term monitoring are needed by the rapidly growing industry, as well as by the U.S. Department of Energy in evaluating progress by solar technology development initiatives. This paper describes an improved model for rating and monitoring PV array performance, discusses initial results from an outdoor laboratory designed to assist industry in optimizing system components and integration, and provides a brief discussion of the system performance metrics currently being used by the PV community

This paper deals with the technology transfer of a specific photovoltaic (PV) module characterization procedure from Sandia National Laboratories (Sandia) to Arizona State University Photovoltaic Testing Laboratory (ASU-PTL). This effort was intended to meet industry requests for independent module performance testing that provides the parameters (coefficients) required by the Sandia performance model. The objective of this work was two fold: (i) implement Sandia's experimental methodology at ASU-PTL to collect and analyze sunrise-to-sunset module performance data; and (ii) validate Sandia's performance model by comparing the modeled performance based on analysis of daylong data sets with performance determined using traditional standardized procedures. This paper reports lessons learned as well as the successful completion of this effort.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since June 2004 are reviewed. Copyright (C) 2005 John Wiley Sons, Ltd.

This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since January 2003 are reviewed. Copyright © 2003 John Wiley & Sons, Ltd.

The most relevant basis for designing photovoltaic systems is their annual energy production, which is also the best metric for monitoring their long-term performance. An accurate array performance model based on established testing procedures is required to confidently predict energy available from the array. This model, coupled with the performance characteristics of other balance-of-system components, provides the tool necessary to calculate expected system performance and to compare actual versus expected energy production. Using such a tool, this paper quantifies the effect of the primary factors influencing the DC-energy available from different photovoltaic module technologies, and contrasts these influences with other system-level factors that often result in significantly less AC-energy delivered to the load than the array is capable of providing. Annual as well as seasonal energy production is discussed in the context of both grid-tied and stand-alone photovoltaic systems.

Degradation leading to failure in photovoltaic modules follows a progression that is dependent on multiple factors, some of which interact causing degradation that is difficult to simulate in the lab. This paper defines observed degradation in field-aged modules, including degradation of packaging materials, adhesional loss, degradation of interconnects, degradation due to moisture intrusion, and semiconductor device degradation. Additionally, this paper suggests that the onset and progression of degradation need to be studied to gain a more comprehensive understanding of module degradation rates and module failures.

Stand-alone photovoltaic systems are deceptively complex. Optimizing the performance and reliability of these systems requires a complete understanding of their behavior as a function of site-dependent environmental conditions. Individual component specifications provide useful design information. However, to fully understand the interactions between components, it is necessary to simultaneously characterize the performance of the system and its separate components under actual operating conditions. T his paper describes how a new 30-day outdoor testing procedure was coupled with array performance modeling to accomplish this objective. The procedure measures battery capacity, determines appropriate set-points for charging, and based on daily intervals quantifies dc-energy available from the array, charge-controller efficiency,. battery efficiency, Inverter efficiency, overall system efficiency, days of autonomy, and,ac-energy available by month.

The objective of this study was to investigate the technology used by Spectrolab Inc. to manufacture photovoltaic modules that have provided twenty years of reliable service at Natural Bridges National Monument in southeastern Utah. A field survey, system performance tests, and a series of module and materials tests have confirmed the durability of the modules in the array. The combination of manufacturing processes, materials, and quality controls used by Spectrolab resulted in modules that have maintained a performance level close to the original specifications for twenty years. Specific contributors to the durability of the modules included polyvinyl-butyral (PVB) encapsulant, expanded metal interconnects, silicon oxide anti-reflective coating, and excellent solder/substrate solderability.

Anomalous temperature distributions are often an indication of atypical behavior in a device under investigation. Portable infrared (IR) imaging systems (cameras) now provide a convenient method for measuring both absolute and relative temperature distributions on small and large components with a high degree of temperature and spatial resolution. This diagnostic tool can be applied during the development, production, monitoring, and repair of photovoltaic cells, modules, and systems. Planar objects with nearly uniform material composition are ideally suited for analysis using IR imaging. This paper illustrates investigations of localized shunting in cells, resistive solder bonds in field-aged modules, module bypass diode functionality, reverse-bias (hot spot) heating in modules, temperature distributions in flat-plate and concentrator modules, batteries during charging, and electronic component temperature in power processing equipment.

The rating and modeling of photovoltaic (PV) module performance has been of concern to manufacturers and system designers for over 20 years. Both the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL) have developed methodologies to predict module and array performance under actual operating conditions. This paper compares the two methods of determining the performance of PV modules. The methods translate module performance to actual or reference conditions using slightly different approaches. The accuracy of both methods is compared for both hourly, daily, and annual energy production over a year of data recorded at NREL in Golden, CO, USA. The comparison of the two methods is presented for five different PV module technologies

The accuracy of solar cells calibrated as primary reference cells is directly dependent on the accuracy of the pyrheliometer used to measure the direct beam solar irradiance on the cell. Pyrheliometers are also used in measuring performance of concentrating photovoltaic modules. In order to reduce errors in photovoltaic performance measurements, we have investigated the calibration uncertainties for pyrheliometers from two manufacturers. Our calibration comparisons are relative to an absolute cavity radiometer traceable to the World Radiometric Reference. This paper quantifies the effects of aging, temperature, time-rate-of-change of temperature, wind, solar spectral shifts, linearity, window transmission, and solar tracking on pyrheliometer calibrations. Uncertainty remaining after accounting for these factors is 0.8% at the 2-sigma level.