Agricultural residues, including straw, are important energy feedstock for electricity generation. This study aims to develop a model for energy and environmental assessment of straw production, taking into account its life cycle. The proposed mathematical model allows us to distribute input energy (into any crop production) and emit carbon dioxide (during crop production) between grain and straw formation. It takes into account direct energy input (fuels, electricity, etc.), indirect energy input (fertilizer, herbicide, etc.), and energy required in manufacturing agricultural tractors and implements. It has been found that straw formation consumes from 41 to 66 % of the total energy input and CO2 emissions.