## 1 Introduction  
The energy industry that fulfills the principles of sustainable development requires the minimization of emissions of pollutants generated by burning fossil fuels, including greenhouse gas emissions that negatively affect the climate. The most effective alternative to fossil fuel energy in terms of environmental performance is renewable energy sources (RES). Currently, more than a hundred countries are developing programs to support the adoption of renewable energy [1]. In some cases, the issue of creating energy systems based exclusively on renewable energy sources is raised [2].  
Among RESs, solar and wind energy sources are developing at the fastest pace [1]. Their key feature is the random (stochastic) nature of power generation that depends on variable weather conditions. In this regard, they require either their capacity to be backed up by other energy sources or the use of energy storage units (batteries). Mutual redundancy also takes place in hybrid energy systems that include different types of RESs [3; 4; 5]. Solar and wind energy conversion technologies have recently become economically feasible, but problems remain in meeting end-user requirements for reliability and uninterrupted electric power supply. An important renewable energy source is woody biomass, the burning of which, first, recycles waste from the forest and wood processing industry and, second, does not change the balance of CO\({}_{2}\) in the atmosphere [6; 7].  
Solar and wind energy resources are available everywhere and differ only in their energy potential. Biomass resources are distributed more unevenly. Fuel is relatively inexpensive when using logging and wood processing waste, but its availability and resources depend on the location of a given settlement.  
The main forest reserves in Russia are concentrated in Siberia, the Russian Far East, and the Russian North. The share of the forest-covered area is highest in the Irkutsk region and Primorsky Krai, while it is slightly lower in the south of Khabarovsk Krai; the south of Yakutia; in the part of Krasnoyarsk Krai adjacent to the Yenisey River and in the Komi Republic; and the Vologda, Kostroma, and Perm regions. In many regions of European Russia, forest resources are much smaller, and the energy potential of woody biomass is insignificant. These regions should pay special attention to afforestation and strengthen logging control.  
The main waste resources for wood fuel are concentrated in the Irkutsk region, which consistently ranks first among Russian regions in the volume of logging and is also one of the largest producers of lumber and pulp. The region is often viewed as part of the Baikal region (along with Buryatia and Zabaikalsky Krai). The Baikal region has unique forest resources; therefore, the prospects for their use are given special attention in this study.  
This paper aims to evaluate woody biomass resources and consider advanced technologies and their cost-effectiveness when they are employed for energy use in various climatic zones of the Baikal region of Russia.  
Lake Baikal is a world cultural heritage site [8] and the requirement to minimize environmental pollution and boost the use of renewable energy is especially relevant. Therefore, in addition to [9; 10] that compared gasification power plants with fossil fuel-fired energy sources, this study focuses on their comparison with wind and solar power plants, including hybrid energy systems, which consist of renewable energy sources of different types. An optimization mathematical model is used to determine the optimal structure of the system, study its operating conditions, and determine economic indicators.  
An Overview of Woody Biomass Resources and Technologies for Its Energy Use in Hybrid Energy Systems with Renewable Energy Sources