The energy obtained from biomass in the global balance of energy carriers is the largest source among all RES. It should be borne in mind that the share of biomass as an energy carrier in the total balance is as much as 14%. The basic sources of renewable energy used in Poland are the wind power industry and biomass. Organic chemical compounds are the source of chemical energy for biomass. The biomass can be used in a solid form (wood, straw) or after being converted to liquid (alcohol, bio-oil) or gas (biogas) form.

Pellets, meaning, the type of fuel of natural origin created from biomass compressed under high pressure without the participation of any chemical adhesive substances are recognized as the most common and available grades of biomass. Wood pellets manufactured from sawdust, shaving, or woodchips are the most popular type of pellets on the market. Fuel created in the form of granules is very dense and can be manufactured with low humidity content, which translates into an exceptionally high burn efficiency.

The authors of this article burned agro pellets from Miscanthus giganteus without additives and with solid catalyst and conducted a series of tests that determine the impact of boiler settings (blast power, time of feeding, chimney draft) on the process of burning fuel in real conditions. A solid catalyst was used to improve combustion conditions in one of the fuels. The catalyst burns carbon monoxide and reduces nitrogen oxides. The results in the form of observation of selected parameters are summarized in the table.

Wood pellets, commonly referred to as biomass fuel, are increasingly used in heating and district heating in the European Union countries, including Poland. Their use in class 5 and/or Ecodesign boilers enables an individual consumer to use energy from renewable sources, reduce the environmental burden by reducing the emission of harmful compounds, and provides a sense of comfort by automating the boiler system. The article presents the current situation in the global wood pellet market, describes the basic quality standards applicable to this fuel during production, and indicates the difficulties in the implementation of programs co-financing the replacement of obsolete coal-fired boilers with automatic class 5 biomass-fired boilers. The research presented in this article is focused on the presence of contaminants in the DIN Plus, EN Plus, and A1 pellets, as well as in non-certified pellets. The analysis has shown that the use of wood pellets containing prohibited substances negatively affects boiler operation and contributes to the formation of slag and the emission of harmful compounds, making the discussed fuel non-ecological.