Climate performance of liquefied biomethane with carbon dioxide utilization or storage

• Published in: Renewable & sustainable energy reviews 2024-03, Vol.192, p.114239, Article 114239
• Main Authors: Gustafsson, Marcus, Cordova, Stephanie S., Svensson, Niclas, Eklund, Mats
• Format: Article
• Language: English
• Subjects: Biogas upgrading; Biomethane; Climate performance; CO₂ utilization; Life cycle assessment
• ISSN: 1364-0321; 1879-0690
• DOI: 10.1016/j.rser.2023.114239

In the process of upgrading biogas to biomethane for gas grid injection or use as a vehicle fuel, biogenic carbon dioxide (CO₂) is separated and normally emitted to the atmosphere. Meanwhile, there are a number of ways of utilizing CO₂ to reduce the dependency on fossil carbon sources. This article assesses the climate performance of liquefied biomethane for road transport with different options for utilization or storage of CO₂. The analysis is done from a life cycle perspective, covering the required and avoided processes from biogas production to the end use of biomethane and CO₂. The results show that all of the studied options for CO₂ utilization can improve the climate performance of biomethane, in some cases contributing to negative CO₂ emissions. One of the best options, from a climate impact perspective, is to use the CO₂ internally to produce more methane, although continuous supply of hydrogen from renewable sources can be a challenge. Another option that stands out is concrete curing, where CO₂ can both replace conventional steam curing and be stored for a long time in mineral form. Storing CO₂ in geological formations can also lead to negative CO₂ emissions. However, with such long-term storage solutions, opportunities to recycle biogenic CO₂ are lost, together with the possibility of de-fossilizing processes that require carbon, such as chemical production and horticulture. •Climate performance assessment of CO₂ utilization options for biomethane production.•Negative CO₂ emissions is attainable for four of the six CO₂ utilization pathways.•Methanation is a good option, given adequate access to renewable hydrogen.•Many CO₂ pathways improve climate performance and contribute to de-fossilization.•Utilization of CO₂ from biomethane can give lower climate impact than storage.