Microalgal Technology for Remediation of CO2 from Power Plant Flue Gas: A Technoeconomic Overview

Power plants burning fossil fuels are a major source of CO2, which is implicated in global warming. Microalgal systems, which photosynthetically assimilate CO2, can be used to mitigate this major greenhouse gas. A technoeconomic model was developed for trapping CO2 from flue gases by microalgae in outdoor ponds. The model allows us to make some notable observations about the microalgal process.For example, although it was known that the delivered CO2 cost is an important parameter, this model demonstrates in quantitative terms that the targeted improvements for productivity and lipid content double the relative impace of CO2 resource cost on total annualized cost of the technology. The model also shows that both algal lipid content and growth rate are important for the economicalprocess, but a trade-off exists between the two, i.e., a high lipid content and low growth rate combination can be as effective as a low lipid content and high growth rate combination. Model predictions were also used to compare the microalgal technology with alternative technologies in terms of CO2 mitigation costs. The mid-term process, which can be implemented in the near future, iscompetitive with other CO2 remediation technologies currently being proposed. Incorporating anticipated advances into the design basis, a CO2 mitigation cost of $30/t (CO2 avoided basis) is obtained for the long-term process, which is very promising. Deployment of this technology for CO2 mitigation looks attractive if research goals put forth by the model are achieved.