This work includes calculations of the cumulative CO₂ emissions of two comparable cars—the VW Golf VII—one with a combustion engine and the other with an electric motor. Calculation of CO₂ emissions was performed, taking into account the stages of production, utilization and use of the above-mentioned vehicles. For the use phase, it was assumed that the total mileage of the car will be 150,000 km over 10 years. For the electric vehicle, calculations were made assuming five different sources of electricity (from coal only, from natural gas only, from PV and wind turbines, an average mix of European power sources and an average mix of Polish power sources; W1–W5 designations, respectively). For individual sources of electricity, cumulative CO₂ emissions were taken into account, that is, resulting both from the production of electricity and the use of the resources (for example, technical service per 1 kWh of electricity produced). The obtained results of the analysis show that for the adopted assumptions regarding operation, for variants W2–W5, the use of an electric car results in lower cumulative CO₂ emission than a the use of a combustion car. For a combustion car, the value was 37,000 kg-CO₂, and for an electric car, depending on the variant, the value was 43, 31, 16, 23 and 34 thousand kg-CO₂ for variants W1 to W5, respectively. Based on the emissions results obtained for individual stages of the use of selected vehicles, a comparative analysis of cumulative CO₂ emissions was performed. The purpose of this analysis was to determine whether the replacement of an existing combustion car (that has already been manufactured; therefore, this part of the analysis does not include CO₂ emissions in the production stage) with a new electric car, which has to be manufactured, therefore associated with additional CO₂ emissions, would reduce cumulative CO₂ emissions. Considering three adopted average annual car mileages (3000, 7500 and 15,000 km) and the previously described power options (W1–W5), we sought an answer as to whether the use of a new electric car would be burdened with lower cumulative CO₂ emissions. In this case we assumed an analysis time of 15 years. For the worst variant from the point of view of CO₂ emissions (W1, electricity from coal power sources only), further use of a combustion car is associated with lower cumulative CO₂ emissions than the purchase of a new electric car over the entire analyzed period of 15 years. In turn, for the most advantageous variant (W3, electricity from PV or wind power sources) with an annual mileage of 3000 km, the purchase of a new electric car results in higher cumulative CO₂ emissions throughout the analyzed period, whereas for an annual milage of 7500 or 15,000 km, replacing the car with an electric car “pays back” in terms of cumulative CO₂ emissions after 8.5 or 4 years, respectively.

The immense popularity of coffee around the world generates significant amounts of coffee grounds. They are often improperly disposed of, which can have a negative impact on the environment. Due to their chemical composition and physical properties, coffee grounds are an excellent bioenergy material. This paper presents a study of the feasibility of using spent coffee grounds (CG) as an additive to pine sawdust (PS) pellets to improve their energy properties. The tests were carried out on samples of pellets consisting of 100% PS, 100% CG, and mixtures of 95% PS and 5% CG, 85% PS and 15% CG, and 70% PS and 30% CG. Physical and chemical analyses were carried out to determine the suitability of the obtained pellet as a biofuel in accordance with ISO 17225. Combustion tests were also carried out in a laboratory boiler to analyze flue gases and determine CO and NO_x emissions in accordance with EN-303-5 for biomass boilers. The amount of emitted volatile organic compounds (VOCs) was also determined. Experimental results show that the addition of CG to PS reduces the durability of the pellets and increases CO and NO_x emissions but increases their energy value and reduces the amount of VOC emissions. The requirements of both standards were fulfilled with a mixture of 95% PS and 5% CG. However, test results show that it is possible to add CG to PS in amounts up to 15%, although this will require additional research.