Integration of geological sequestration and microalgae biofixation supply chains for better greenhouse gas emission abatement

This paper studies the integration of geological sequestration and microalgae biofixation options for greenhouse gas (GHG) abatement using a supply chain optimisation approach. We propose a multi-scale multi-period mixed-integer nonlinear programming (MINLP) model, which accounts for CO₂ transportation pipeline network design, algae processing route and product selection, as well as the seasonality in CO₂ source availability and algal biomass productivity. The model considers pipeline transportation of both supercritical CO₂ and feed gas. The economic and environmental performances are simultaneously optimized using the Life Cycle Optimisation framework. Improved branch-and-refine algorithm is employed to effectively solve the resulting non-convex MINLP problems. A case study is presented to demonstrate the optimal design of potential CO₂ capture, utilization, and storage infrastructures in Texas.