Biogas production from waste biomass can create many sustainability-related benefits. However, the CO₂ produced in the process is rarely put to use, although it is often pure and could potentially add value and improve the climate performance if utilized or stored. This study applies life cycle assessment methodology to estimate the overall environmental performance of a biogas system including utilization (CCU) or storage (CCS) of CO₂, comparing six different utilization options and geological storage. The results show that CCU can improve many aspects of the environmental performance of biogas, for example by using CO₂ with renewable hydrogen to produce methane or methanol, as the CO₂ from biogas production can then replace fossil-based processes. Meanwhile, CCS only reduces the climate impact, but increases environmental impact in all other studied categories, as it requires additional processes to treat the CO₂. Utilizing CO₂ from biogas, on the other hand, could be an instrument in the work towards a bioeconomy with reduced fossil resource dependence and improved environmental sustainability. © 2024, ETA-Florence Renewable Energies. All rights reserved.