Synergies between Geological Sequestration and Microalgae Biofixation for Greenhouse Gas Abatement: Life Cycle Design of Carbon Capture, Utilization, and Storage Supply Chains

We address the integration of two greenhouse gas (GHG) abatement options, namely, geological sequestration and microalgae biofixation, using a supply chain optimization approach. A multiscale, multiperiod, mixed-integer nonlinear programming (MINLP) model is proposed, which accounts for CO 2 transportation pipeline network design, algae processing route, and product selection, as well as the seasonality in CO 2 source availability and algal biomass productivity. The model allows for pipeline transportation of both supercritical CO 2 and feed gas. By using the Life Cycle Optimization framework, we simultaneously optimize the economic and environmental performances. We employ an improved branch-and-refine algorithm for efficient global optimization of the resulting nonconvex MINLP problems. We consider a case study on the optimal design of potential CO 2 capture, utilization, and storage infrastructures in the state of Texas. By taking advantage of the synergies between these two GHG abatement options, the CO 2 emissions can be sequestrated and utilized at an average cost of $45.52/tCO 2, and about 64% of the GHGs can be avoided from entering the atmosphere.