A catalogue is set up describing the quality characteristics relevant for the combustion of biomass to be used as solid fuel. The practical relevance of these characteristics is discussed. The main characteristics are water concentration, the concentration of chloride and ash, the heating value and the concentration of volatiles and remaining coke. Further quality criteria are the concentrations of nitrogen, sulphur, potassium and calcium.
In multifactorial field trials at three locations, the influence of location, fertilizer application and harvest date on the quality of Miscanthus biomass from 3- and 4-year-old plantations was tested. The concentrations of water, minerals and ash, all three of which should be as low as possible, were higher in biomass from the cool and humid than in biomass from the warm location. The application of potassium fertilizer led to increases in the ash and potassium concentrations. Harvesting Miscanthus in February instead of December led to an improved biomass quality because the concentrations of ash, minerals and especially of water had declined.