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Solid biofuels, including wood chips, are still the most important feedstock in the structure of primary energy production from renewable energy sources. Wood chips are derived mainly from forests and the wood industry, including sawmills. However, the considerable diversity of chipper types results in great differences in their final production efficiency. The objective of this study was to analyze and evaluate the efficiency of three mobile chippers used in wood chip production by determining their throughput rate, diesel fuel and energy consumption, cost of chipping and greenhouse gas emission, as well as the quality of the chips. By far shortest time (0.82 min. Mg−1) of producing 1 Mg of wood chips was found for the Albach 565 kW chipper. Moreover, the mean time needed for the production of 1 Mg of chips with a chipper of the same make but with a smaller engine (Albach 515 kW) was 8.8% longer. This time was 284.9% longer than when the Bruks chipper was used. However, the highest mean effectiveness of diesel fuel use (expressed as the lowest diesel fuel consumption of 1.41 dm3 Mg−1), the lowest energy consumption (52.02 MJ Mg−1), the lowest cost of diesel fuel use (2.28 € Mg−1) and the lowest GHG emission (4.27 kg Mg−1 CO2eq) in wood chip production were determined for the Albach 515 kW chipper. In contrast, the poorest parameters were determined for the Bruks chipper.

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Due to the ending resources of fossil fuels, as well as instability of the political situation on the world, especially in countries that are their main supplier, governments of poor countries in resources are forced to seek alternative sources of energy.Currently the most commonly used raw material to produce an electrical and thermal power in Poland are coal and lignite, However, in a result of an increase of their prices and an exacerbated by the EU of regulations about an emission of the greenhouse gas, emerged trends, that aim to transform the energy sector through the implementation of technologies based on alternative energy sources. The main focus is to put on renewable energy sources.The methodology, which is contained in this paper, presents a way to designation the demand of the biogas plant with CHP system on substrate of agricultural origin, the aim to obtain required electrical and thermal power. Moreover, the paper presents a simplified diagram of anaerobic fermentation, which is the basis of biogas production, as well as an illustrative diagram of a biogas plant with CHP system. In this paper also was mentioned the possibility of application biogas for transportation purposes.