Physico-chemical characteristics of eight different biomass fuels and comparison of combustion and emission results in a small scale multi-fuel boiler

•Physical parameters of the eight biomass fuels examined were all different.•Significant differences were found in Proximate, Ultimate and TGA results.•Energy outputs were not proportionate to dry matter energy content.•Highest flue ash production from fuels with highest fines content.•Flue gas emissions varied significantly, NOx levels correlated with fuel N content. This study describes the results from the investigation of 7 different biomass fuel types produced on a farm, and a commercial grade wood pellet, for their physical, chemical, thermo-gravimetric and combustion properties. Three types of short rotation coppice (SRC) willow, two species of conifers, forest residues (brash), commercially produced wood-pellets and a chop harvested energy grass crop Miscanthus giganteus spp., (elephant grass) were investigated. Significant differences (p