Tracker accuracy: field experience, analysis, and correlation with meteorological conditions

Tracker performance is a significant factor in the energy production of PV systems, especially concentrating photo-voltaic (CPV) systems. The nonlinear relationship between CPV optic pointing accuracy and energy production means that simple metrics such as mean pointing accuracy are not sufficient for predicting performance of these systems. Additionally, trackers are currently a significant component of system cost. Understanding the real causes of tracking errors in the field (as well as which types of errors have a less significant impact on energy production) is an important step towards the development of lower-cost tracking systems. In this paper we present a collection of real-world data, including tracking error and corresponding meteorological data, gathered over a period of months from commercial solar trackers installed at Instituto de Sistemas Fotovoltaicos de Concentracion S.A. (ISFOC) in Puertollano, Spain. We present several relevant mathematical tools for analyzing this data, and draw conclusions about the implications of tracking errors for system energy production.