This thesis contains the development of a software capable of evaluating the performance of ten unique photovoltaic (PV) systems located 10 kilometers outside of Västerås, Sweden. The ten systems have different configurations according to this list: Dual-axis tracking Single-axis tracking with 30°tilt Ground mounted, free-standing with 19° tilt Ground mounted, free-standing with 41° tilt Roof mounted with 19°tilt   Each of the above configurations exist with and without installed power optimizers adding up to a total of ten unique systems. The development goal for the evaluation software is to provide the user with a variety of tools to determine which of the systems that has the best yield and performance. Integrated in the development of the software is therefore a literature study where it is investigate how photovoltaic systems operate and especially how their performance can be evaluated. Some of the frequently used parameters are; system yield, reference yield and performance ratio. The software features are focused around presenting the data collected from the PV systems in a variety of graphs. The different types of graph are designed to let the user easy compare the data between the systems and thus find how and why a particular system is performing better than the others. The software is developed in a Matlab environment and has an intuitive user interface. The thesis time-frame is too short for any conclusive result to be presented, but to showcase the software features a short-termed evaluation of the systems have been performed. The period evaluated is a three week period in the middle of May 2014. The short-termed evaluation highlights several scenarios and issues that can arise. It has been detected throughout the project that it is difficult to separate which effects that causes one system to be better than the other. Irregularities seen in the data can be caused by many factors. Some of the more evident are; installed power optimizers, differences in system configurations and shadow patterns. By using the software effects like array shading and inaccurate measurements has been discovered. / Evaluation of first MW PV plant in Sweden