###### Abstract  
The depletion of fossil fuels and climate change concerns are drivers for the development and expansion of bioenergy. Promoting biomass is vital to move civilization toward a low-carbon economy. To meet European Union targets, it is required to increase the use of agricultural residues (including straw) for power generation. Using agricultural residues without accounting for their energy consumed and carbon dioxide emissions distorts the energy and environmental balance, and their analysis is the purpose of this study. In this paper, a life cycle analysis method is applied. The allocation of carbon dioxide emissions and energy inputs in the crop production by allocating between a product (grain) and a byproduct (straw) is modeled. Selected crop yield and the residue-to-crop ratio impact on the above indicators are investigated. We reveal that straw formation can consume between 30% and 70% of the total energy inputs and, therefore, emits relative carbon dioxide emissions. For cereal crops, this energy can be up to 40% of the lower heating value of straw. Energy and environmental indicators of a straw return-to-field technology and straw power generation systems are examined. bioenergy; agricultural residues; power generation; energy; energy analysis +
Footnote †: journal: Applied Sciences  
0021  
11 Department of Tractors and Agricultural Machines, Operating and Maintenance, Mykolayiv National  
biomass power supply systems. Use of agricultural residues is one of the solutions to this problem. Bioeconomy strategies have been developed by a number of countries [9]. This concept is a spotlight of numerous researches [10]. Currently, the 100% renewable energy concept is accepted by a number of countries such as Sweden, Denmark, Bangladesh, Vietnam, Hawaii in the United States, etc. [11; 12]. [PERSON] et al. [11] analyzed the status and perspective on 100% renewable energy systems. Many countries have approved political phase-out decisions regarding nuclear and coal-fired plants [13; 14; 15]. An alternative to these energy resources is renewable energy biomass. This enables the expansion of renewable power generation. Since 2009, bioenergy has been promoted by the European Union (EU) as a low-carbon source [16]. The EU strategy is aimed at increasing renewable energy consumption and the reduction in the greenhouse gas emissions [17; 18]. Biomass consumption for heat and power generation is increasing [19]. Agricultural residues enable some of this growth [20]. [PERSON] and [PERSON] applied a dynamic optimization model to analyze the role of biomass feedstock in the European power generation system in the context of emissions targets for 2050 [21]. The large-scale application of wind and solar power plants has resulted in a number of challenges such as power quality, power balance, flow, stability, etc. [22]. These technologies are variable in the short and long terms. In power supply systems, biomass-based power plants could be used to complement wind and solar power plants and to improve the power stability situation [23]. Agricultural residues are sources of bioenergy worldwide because of their renewability and carbon neutrality. They can be used to generate electricity (direct burning) [24; 25; 26; 20], biogas production [27; 28], for conversion to bioethanol [29], and to produce solid fuels [30]. The use of agricultural crop residues has environmental benefits compared with fossil fuels [31; 32; 33; 34]. The use of straw as a source of bioenergy complies with the renewable energy directive of the EU for the period 2021-2030 [35]. Straw is a byproduct of cereal and other crops. Off-field straw could be converted into energy resources such as biogas, bioethanol, heat, and electricity. A detailed understanding of the straw production system is essential to the proper evaluation of energy and environmental indicators [36]. Life cycle energy consumption and carbon dioxide emissions are currently critical information for the development of appropriate energy policy [37; 38].