The goal of investigation was assessment of environmental impact and economic efficiency of composite briquette production on the base of peat and renewable biomass. Biomass for composite briquettes was obtained from straw (cereal crops and rape) and wood residues (sawdust, chips) Experimental composite briquette were produced from the mixture of peat and biomass in relation to – 25 : 75, 50 : 50, 75 : 25. The technological cards of biomass feedstock production for 6 variants were developed. Technological cards were used for calculation of emission into the atmosphere during life cycle of biomass production and prime cost of biomass. The lowest volume of gas (SO2, NOx, CO2) and particulate matter (PM) emission was installed for biomass production from the sawdust. The highest volume of emission was installed for production of biomass from the straw with pressing it in standard bale. The volume of CO2 emission for the sawdust production was 6 kg per ton of biomass and for the standard bale of straw was 19 kg per ton of biomass. Prime cost of sawdust production (lowest) was 11 belarusian rubles per ton of biomass, for the wood chips was 19 rubles per ton and for the straw varied from 26 to 33 rubles per ton in depend of technology. It was installed that growth of biomass rate in composite briquette had a good influence on number of basic fuel characteristics (contents of ash, sulfur and moisture). The variation of calorific value of briquette was not significant in depend of biomass contents. In accordance with assessment of all characteristics the better briquettes was obtained from the peat and sawdust.