The assessment of engineering objects in terms of energy consumption is an important part of sustainable development. Many materials, including those from the energy sector, need to undergo earlier processing, e.g., grinding. Grinding processes still demand a significant amount of energy, whereas current energy assessment methods do not take into account important parameters of the process, which makes it difficult to choose their optimal values. The study presents the analysis, testing, and assessment of mechanical engineering systems in terms of the energy consumption involved in the grinding of biomass intended for energy production purposes. A testing methodology was developed to improve the parameters of multi-disc grinding, including the reduction of energy consumption, power input, product quality improvement, and process efficiency. An original model of integrated energy consumption was developed. Tests were carried out on a five-disc grinder for five programs to assess the programmable angular speeds of the grinder discs. Output values, including specific energy demand, fragmentation degree, and integrated energy consumption, were assigned to each testing program. The test results were subjected to statistical analysis. Based on the authors' own research, it was found that the angular speed of the discs and, consequently, the linear speed of the grinding blades, have a significant influence on the values of the integrated energy consumption of the preliminary process.Acquiring energy from biomass requires its earlier preparation: drying, grinding, palletizing, etc. [7]. These procedures require certain energy inputs (costs) which significantly decrease the energy and environmental balance in the entire lifecycle of the energy material (wood, grain biomass, etc.) [8][9][10][11][12][13]. According to the idea of sustainable development concerning the design of systems, devices, and processes, in three areas-the environment, society, and economy-the biomass processing lines should be characterized by the lowest possible energy consumption and environmental impact [14,15]. It also aims to improve the competitiveness of biomass fuels in relation to conventional fossil fuels [16,17].Before being used for energy purposes, energy media need to be properly prepared, e.g., their dimensions need to be reduced by means of grinding [2]. Roller, drum, ball, hammer, and disc mills are used to grind granular biomaterials (biomass grains) [7,18]. Tests have shown that the best relations between product quality, yield, and grinding energy consumption occur for hammer and disc mills [2,7]. The quality of the grinding product is most often determined by the grinding degree, which is defined as the ratio of the characteristic dimensions of the particles before and after size reduction [19,20]. Other indicators, e.g., bulk density, grain size distribution, specific surface area, energy value, and their relationship with the comminution process, are also important from the point of view of the final product quality [4,[21][22]...
