In fossil fuel power generation the usage of online particle sizing in the optimization of the combustion process takes on a greater significance. Pulverized coal is typically used to fire the boiler of power plants. The right particle size distribution of the coal is one of the key factors to an efficient burning process and thus an efficient combustion and low emissions of NOx. However this requires accurate periodic measurements of the coal. In this webinar we summarize the current techniques in use and show how the mobile Insitec laser diffraction system can be applied. Another application is the sizing of the fly ash - a waste product from the combustion process - which is nowadays used as a filler in the cement industry to improve the hydraulic properties of the cement but more importantly produce cements with lightened environmental footprint.