Bioenergy is regarded as cost-effective option to reduce CO2 emissions from fossil fuel combustion. Among newly developed biomass conversion technologies are biomass integrated gas combined cycle plants (BIGCC) as well as ethanol and methanol production based on woody biomass feedstock. Further-more, bioenergy systems with carbon capture and storage (BECS) may allow negative CO2 emissions in the future. It is still not clear which woody biomass conversion technology reduces fossil CO2 emissions at least costs. This article presents a spatial explicit optimization model that assesses new biomass conversion technologies for fuel, heat and power production and compares them with woody pellets for heat production in Austria. The spatial distributions of biomass supply and energy demand have significant impact on the total supply costs of alternative bioenergy systems and are therefore included in the modeling process. Many model parameters that describe new bioenergy technologies are uncertain, because some of the technologies are not commercially developed yet. Monte-Carlo simulations are used to analyze model parameter uncertainty. Model results show that heat production with pellets is to be preferred over BIGCC at low carbon prices while BECS is cost-effective to reduce CO2 emissions at higher carbon prices. Fuel production - methanol as well as ethanol - reduces less CO2 emissions and is therefore less cost-effective in reducing CO2 emissions. (C) 2009 Elsevier Ltd. All rights reserved.