Life-cycle and techno-economic analysis of utility-connected algae systems

For many years, it has been suggested that mitigation of atmospheric carbon dioxide (CO2) emissions can be achieved by fixing CO2 as algal biomass. New EPA regulations limit greenhouse gas emissions from new power plants, and thus power plants have additional impetus to decide if co-location with algal ponds is a feasible strategy for CO2 mitigation. Herein we provide some illustrative benchmarking calculations based on fundamental relationships to highlight the general concerns for algae-utility co-location. We introduce our own life-cycle and techno-economic analysis software to analyze utility-specific concerns, such as total pond area, the percentage of CO2 in the flue gas, and the CO2 utilization efficiency. The results indicate that localized strategies should be pursued to reduce the excessive energy requirements for long-distance CO2 delivery. Furthermore, research should focus on improving the ability of growth reactors to efficiently utilize CO2. Improvements in CO2 delivery methods, such as absorption of CO2 into liquid media, could greatly reduce energy inputs and thus improve the process economics and sustainability.

► New LCA software was developed to analyze algae connection with utilities. ► The potential for CO2 mitigation is closely linked to total algal pond area. ► CO2 utilization efficiency and CO2 concentration should be maximized. ► Alternatives to direct flue gas pumping should be investigated.