Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Comparison of Photovoltaic Module Performance Measurements



Arthur H. Fanney, Mark W. Davis, Brian P. Dougherty, D L. King, W E. Boyson, J A. Kratochvil


Computer simulation tools used to predict the energy production of photovoltaic systems are needed in order to make informed economic decisions. These tools require input parameters that characterize module performance under various operational and environmental conditions. Depending upon the complexity of the simulation model, the required input parameters can vary from the limited information found on labels affixed to photovoltaic modules to an extensive set of parameters. The required input parameters are normally obtained indoors using a solar simulator or flash tester, or measured outdoors under natural sunlight.This paper compares measured performance parameters for three photovoltaic modules tested outdoors at the National Institute of Standards and Technology (NIST) and Sandia National Laboratories (SNL). Two of the three modules were custom fabricated using monocrystalline and silicon film cells. The third, a commercially available module, utilized triple-junction amorphous cells. The resulting data allows a comparison to be made between performance parameters measured at two laboratories with differing geographical locations and apparatus. This paper describes the apparatus used to collect the experimental data, test procedures utilized, and resulting performance parameters for each of the three modules. Using a computer simulation model, the impact that differences in measured parameters have on predicted energy production is quantified.Data presented for each module includes power output at standard rating conditions and the influence of incident angle, air mass, and module temperature on each module s electrical performance.Measurements from the two laboratories are in excellent agreement. The power at standard rating conditions is within 1 percent for all three modules. Although the magnitude of the individual temperature coefficients varied as much as 17 percent between the two laboratories, the impact on predicted performance at various temperature levels was minimal, less than 2 percent. The influence of air mass on the performance of the three modules measured at the laboratories was in excellent agreement. The largest difference in measured results between the two laboratories was noted in the response of the panels to incident angles that exceed 75 degrees
ASME Journal of Solar Energy Engineering
May 2006


comparison, computer simulation tools, measured parameters, performance measurements, photovaltaic module, solar tracking facility


Fanney, A. , Davis, M. , Dougherty, B. , King, D. , Boyson, W. and Kratochvil, J. (2006), Comparison of Photovoltaic Module Performance Measurements, ASME Journal of Solar Energy Engineering, [online], (Accessed June 15, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 2, 2006, Updated February 19, 2017