Our paper presents the results of a study that evaluated the effects of moisture content of plant biomass (Andropogon gerardii) and average particle size on compaction parameters, susceptibility of raw material to compaction, and quality of the obtained agglomerates in the context of energy use. Moisture content of the material was between 10 and 18%. Compaction of the raw material was carried out using the ZWICK Z020/TN2S strength tester and a closed compression die assembly. It was found that along with the growth of moisture content, the following processes were observed: increase in density of plant biomass in the chamber, decrease in density of the agglomerates (after 48 h storage) and compaction work, and increase in expansion of the agglomerate. The increase in moisture content enhanced susceptibility of the raw material to compaction and caused deterioration of the quality of agglomerates in terms of their strength. With an increase in average particle size, density of the agglomerate decreased, work of compaction increased, and strength of the agglomerate decreased. It was shown that the selection of appropriate parameters of the process promotes energy conservation, which is particularly relevant in terms of the impact of the agglomeration process on the environment.