This work is devoted to application of explanatory data analysis in the field of solar plant control and monitoring. Data analysis tasks are discussed that allow discovering useful plant knowledge based on historical data obtained from plant control and monitoring systems. Approaches discussed include both OLAP analysis of plant monitoring data (i.e. multidimensional analysis based on a data warehouse), as well as data mining on plant monitoring data. Some of the data analysis tasks discussed have been realized based on monitoring data from distributed solar collector fields at Plataforma Solar de Almeria in Spain.