Abstract Biomass, in contrast with different type of fossil fuels, is considered a renewable energy source (RES), having a neutral carbon impact in burning processes. As a result, biomass co-firing offers a good potential solution for reducing greenhouse gas emissions in conventional coal fired power plants. This paper evaluates the technical and economic aspects of biomass co-firing electricity production with and without CO2 capture (CC) using different mixtures of coal and sawdust. The impact of biomass co-firing on power plant performances were evaluated in terms of energy efficiency, auxiliary power consumption, capital costs, operational & maintenance (O&M) costs, specific CO2 emissions, electricity cost and CO2 avoidance costs. Depending on the feedstock composition, the biomass co-firing power plant generates 750–800 MW electricity in the case of carbon capture and 980–1027 MW electricity without capture. The results indicate a continuous decrease in both technical and economical performances with the increase of biomass content in the feedstock.