The goal of the project is to enable the use of new “problematic” biomass fuels in small and medium-sized plants (<10 MW) at high efficiencies, low emissions and acceptable costs. This shall be achieved by the development of innovative fuel blending and additivation concepts as well as the further development of existing small and medium-scale combustion technologies. This involves laboratory reactor test runs with new difficult biomass fuels as well as the CFD-based development of fuel flexible technology concepts for fixed-bed combustion systems in the small (<500 kW) and medium-scale (up to 10 MW) as well as their subsequent test and stepwise optimisation and techno-economic analyses of the new technologies.