The role of carbon capture and storage to achieve net-zero energy systems: Trade-offs between economics and the environment

Carbon capture and storage can both reduce greenhouse gas emissions and provide negative emissions to contribute to the transition to a net-zero society. The contribution of carbon capture and storage has been investigated within cross-sectorial energy system models. However, such models commonly focus on cost and greenhouse gas emissions, while broader environmental impacts are investigated for individual technologies only. Here, we analyze economic and environmental impacts of the transition to net-zero emissions by combining energy system modeling with life-cycle assessment. We focus on the system-wide implications of carbon dioxide storage on economic or environmental impacts. In our investigation of the transition of the German energy system until 2045, net-zero emissions require a minimal amount of carbon capture and storage. However, increasing carbon dioxide storage beyond the minimum amount significantly lowers cost and environmental impacts in up to 13 out of 16 impact categories by avoiding investments into material-intensive technologies, such as power-to-methane or renewable power plants in areas with low generation potential. In scenarios without electricity imports, carbon dioxide storage ranges between 118 Mt to 379 Mt in 2045 with cost increasing by 105 % when carbon dioxide storage is minimized. 84 % of the cost increase is incurred for eliminating the final 23 Mt of carbon dioxide stored. The benefits of applying carbon capture and storage are robust to variations in the amount of renewable electricity imports and residual emissions that require compensation. Hence, the results suggest that carbon capture and storage can offer economic and environmental benefits in the transition to net-zero energy systems beyond greenhouse gas emission mitigation.