Potential for the valorization of carbon dioxide from biogas production in Sweden

Abstract

Biogas solutions offer many advantages to improve sustainable development, but there is still untapped potential in its environmental performance. During biogas upgrading, CO2 is separated from the gas to deliver a flow with high methane concentration and thus high energy content. In this practice, CO2 is commonly emitted to the atmosphere without contributing to a net addition of climate gases because of its biological origin, being a missed opportunity for carbon capture. In this paper, CO2 valorization is an option that has been evaluated using a qualitative and quantitative approach, taking Sweden as an example. Results showed that around 140 kt of CO2 can potentially be captured and utilized from biogas upgrading, which can significantly increase in future scenarios. If CO2 were turned into methane using power-to-gas technology, an additional 35% of biogas could be produced in the short term, meaning up to additional 0.7 TWh in 2020. By 2050, around 600 to 1600 kt of CO2 could be available, depending on how well the biogas production develops and how much of the biogas is upgraded, resulting in up to 6.2 TWh of biomethane. The qualitative assessment suggested that only minor modifications in the upgrading process are required for this practice. Biogas actors are interested in getting involved in valorization projects that enhance their circular business and avoid carbon lock-in mainly to improve the environmental performance of biomethane. Moreover, the application of CO2 valorization requires collaboration with different actors to integrate current CO2 demand or innovative transformation technologies.