► 3 LCAs were run comparing various CO2 capture technologies used in biogas upgrading. ► 2 Novel carbon mineralization processes and 6 marketed technologies were studied. ► Carbon mineralization is a viable approach for biogas upgrading. ► One carbon mineralization process has the lowest environment impact. This article evaluates the life cycle assessment (LCA) of three biogas upgrading technologies. An in-depth study and evaluation was conducted on high pressure water scrubbing (HPWS), as well as alkaline with regeneration (AwR) and bottom ash upgrading (BABIU), which additionally offer carbon storage. AwR and BABIU are two novel technologies that utilize waste from municipal solid waste incinerators – namely bottom ash (BA) and air pollution control residues (APC) – and are able to store CO2 from biogas through accelerated carbonation processes. These are compared to high pressure water scrubbing (HPWS) which is a widely used technology in Europe. The AwR uses an alkaline solution to remove the CO2 and then the solution – rich in carbonate and bicarbonate ions – is regenerated through carbonation of APC. The BABIU process directly exposes the gas to the BA to remove and immediately store the CO2, again by carbonation. It was determined that the AwR process had an 84% higher impact in all LCA categories largely due to the energy intensive production of the alkaline reactants. The BABIU process had the lowest impact in most categories even when compared to five other CO2 capture technologies on the market. AwR and BABIU have a particularly low impact in the global warming potential category as a result of the immediate storage of the CO2. For AwR, it was determined that using NaOH instead of KOH improves its environmental performance by 34%. For the BABIU process the use of renewable energies would improve its impact since accounts for 55% of the impact.