Experiments were conducted to investigate the electrostatic characteristics of anthracite and biomass powders in a feeding hopper. The effects of fluidization velocity, particle size, and moisture content on the electrostatic characteristics of the powder were determined in the feeding hopper. The empirical correlations of the electrostatic charge for the biomass and anthracite powders were derived. The results indicated that the powder charge to mass ratios increased as the fluidizing velocity increased under the same experimental conditions. The charge to mass ratios of the fine anthracite particles were larger than those of the coarse particles. The biomass powder charge to mass ratios decreased significantly with increasing moisture content. The empirical correlations of the biomass and anthracite powder charge densities were derived from experimental data using dimensional analysis. In general, the predicted values showed good agreement with the experimental data.