Owing to its versatility, biomass can be used for a range of CO 2 mitigation and removal options. The recent adoption of end-of-century temperature targets at the global scale, along with mid-century economy-wide net zero emission targets in Europe, has boosted demand forecasts for this valuable resource. Given the limited nature of sustainable biomass supply, it is important to understand most efficient uses of biomass, both in terms of avoided CO 2 emissions (i.e., substituted energy and economic services) and CO 2 removal. Here, we quantify the mitigation and removal potential of key bio-based CO 2 removal pathways for the transport, power, construction, and iron and steel sectors in Europe. By combining the carbon balance of these pathways with their economics, the optimal use of biomass in terms of CO 2 avoidance and removal costs is quantified, and how these evolve with the decarbonization of the European energy system is discussed.