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The purpose of this work is to develop a model for balancing the processes of the generation and consumption of electricity, taking into account the random nature of these processes. The subject of the study is hybrid power systems that use traditional and renewable energy sources and have the properties of a local network. Such systems are sensitive to variable generation modes, and the presence of rapid changes in power requires short time intervals. The presence of wind and solar power plants makes it difficult to ensure a balance of power, which increases the need for intermediate energy storage. The research method is a mathematical modeling of random processes of energy consumption and generation, which allows for the analysis of the current power balancing and the obtaining of the integrated characteristics of the state of energy storage and reuse. The unique goal of the study is to take into account the power gradients and the state of charge of the batteries. The results of the study allow for the comparison of the different configurations of the power system in terms of balance, storage needs, and energy loss. It has been shown that the increase in battery capacity and speed limitations are nonlinearly related to the possibilities of energy conservation and the probability of the incomplete use of the capabilities of the energy storage system. [ABSTRACT FROM AUTHOR]

This study aimed to determine the productivity and energy values of 10 poplar cultivars for use as potential fuel sources in Poland. The study was conducted over a seven-year cycle in northern Poland. The cultivars belonged to clones traditionally used for timber production, as well as new clones specific to short-rotation coppice (SRC) practices. Biomass production and biomass properties were measured, including elemental composition, the gross and net calorific values (heating value) of wood, and envelope density. For each cultivar, the synthetic fuel value index (FVI) was calculated. Biomass dry matter (DM) production differed noticeably between cultivars, and it was the highest for traditional cultivars (‘NE-42’ and ‘Fritzi Pauley’, amounting to 8 Mg ha −1 yr −1 ), and the lowest for new cultivars (DM was one-third that of the cultivars with the highest production). Two traditional cultivars (‘NE-42’ and ‘Fritzi Pauley’) had the highest FVI, representing potential biofuels, whereas two new SRC cultivars (‘AF-8’ and ‘AF-2’) had the lowest indexes. Overall, poplar plantations with short rotations could be considered as a potential additional source of renewable energy in Poland. However, the key factor is selection of appropriate genotypes for the specific climatic conditions. In conclusion, our study demonstrated the importance of testing cultivars under local climatic conditions before using them at a commercial scale. [ABSTRACT FROM AUTHOR]