Biomass is considered a low carbon source for various energy or chemical options. This paper assesses it′s different possible uses, the competition between these uses, and the implications for long-term global energy demand and energy-system emissions. A scenario analysis is performed using the TIMER energy system model. Under baseline conditions, 170 EJ/yr of secondary bioenergy is consumed in 2100 (approximately 18% of total secondary energy demand), used primarily in the transport, buildings and non-energy (chemical production) sectors. This leads to a reduction of 9% of CO2 emissions compared to a counterfactual scenario where no bioenergy is used. Bioenergy can contribute up to 40% reduction of emissions at carbon taxes greater than 500$/tC. As higher CO2 taxes are applied, bioenergy is increasingly diverted towards electricity generation. Results are more sensitive to assumptions about resource availability than about technological parameters. To estimate the effectiveness of bioenergy in specific sectors, experiments are performed in which bioenergy is only allowed in one sector at the time. The results show that cross-sectoral leakage and emissions from biomass conversion limit the total emission reduction possible in each sector. In terms of reducing emissions per unit of bioenergy use, we show that the use of bioelectricity is the most effective, especially when used with carbon capture and storage. However, this technology only penetrates at a high carbon price (>100$/tC) and competition with transport fuels may limit its adoption.This article is protected by copyright. All rights reserved.