The study evaluated physicochemical properties of bio-waste as a potential biofuel in the form of leaves from ‘Regent’ grapevines grown on six different rootstocks and a control grown on its own roots for three years of cultivation. An elemental analysis was carried out, determining the content of carbon, hydrogen, nitrogen, and sulphur in the leaves tested. A technical analysis of the biofuel was also carried out to determine the content of moisture, volatile matter, and ash. The calorimetric method was used to determine the higher heating value for the material. Fixed carbon and oxygen carbon was calculated based on the elemental and technical analyses. The study showed that the type of rootstock and the year of cultivation influence the amount of leaves obtained from the cultivation area. Leaf entrustment per hectare ranged from 1,140,868.02 in rootstock 161-49 to 1,265,286.7 Mg∙ha–1 in rootstock SO4. Regardless of the year of the study, shrubs grafted on 125AA rootstock and the control had the highest combustion heat of 17.5 MJ∙kg–1 and 17.6 MJ∙kg–1 respectively, while 5BB rootstock had the lowest combustion heat (16.4 MJ∙kg–1). Statistical analysis showed no significant effect of test year on the elemental and technical parameters evaluated. It was observed that regardless of the evaluated parameter and the type of rootstock in most parameters, the values in 2022 were the highest, while in 2021 they were the lowest.

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The article examines the influence of physicochemical traits on yield depending on the variety and year of cultivation. Four common to Poland grape cultivars, i.e. ‘Regent’, ‘Rondo’, ‘Seyval Blanc’, and ‘Solaris’, were evaluated by analysing, among others, number of clusters per bush, their weight, number of berries, and the yield per hectare, number of woody shoots, weight of woody shoots, and the diameter of woody shoots. Energy and emission parameters were evaluated by conducting technical evaluation (lower heating value, ash content, volatile matters content, moisture content, fixed carbon) and elemental analysis (carbon, nitrogen, hydrogen, sulphur and oxygen contents) of one-year, two-year and three-year vine shoots. In addition, emission factors for CO, CO2, NOx, SO2 and dust were estimated. The study showed that there was no significant differences between years under study (2020, 2021 and 2022) and energy and emission parameters. It was observed that the highest LHV (lower heating value) occurred in the ‘Regent’ cultivar while the lowest level in the ‘Rondo’ cultivar. As regards energy-emission parameters, a significant influence of cultivar (‘Solaris’, ‘Rondo’, ‘Seyval Blanc’ and ‘Regent’) was shown on the parameters studied except for nitrogen content and NOx emission index. The interaction of year and cultivar showed no significant differences except for the moisture content.

Anaerobic digestion is a demanding process, due to the large number of process and environmental factors that affect it. Many years of research of the various parameters have made it possible to optimise the process to obtain the maximum amount of biogas and methane contained in it, and this provides energy and environmental benefits. The article deals extensively with the operation of agricultural biogas plants, using the example of a plant that faces numerous operational problems. In order to identify the negative effects on energy yield and the equipment operating in the system, the substrate was examined, the data on its operation analysed, and solutions were proposed that should be taken into account in the further operation of the biogas plant. The analysis showed a good biogas yield from beet pulp of 563 dm³∙kg⁻¹ of TS (total solid) and an average methane yield of 58%. With the analysis presented, it was possible to identify some operational problems. The biogas yield study also highlighted some errors made at the plant design stage. The most important of these is the use of an inappropriate organic matter loading factor for the digester, which leads to acidification of the contents and degradation of the methanogenic microorganism cultures.