Utilization of carbon dioxide from fossil fuel-burning power plants with biological systems

Physical-chemical processes for the capture and sequestration of CO 2 from fossil fuel-fired power plant flue-gases are very expensive. Biological processes for CO 2 utilization involve plant photosynthesis and conversion of the biomass to fuels, with no net CO 2 production. Terrestrial plants cannot utilize flue gas CO 2 directly. Only submerged aquatic plants, particularly microalgae, can utilize CO 2 from power plant flue gases in a practical process. Microalgae have the potential for achieving high productivities and can be converted to gaseous and liquid fuels. A preliminary cost-analysis of such a process is presented that suggests that, if high productivities are achievable, overall costs would compare favorably with alternative physical-chemical processes for flue gas CO 2 capture and sequestration, but would be higher than CO 2 mitigation with terrestrial plants. Microalgae CO 2 utilization systems would be most applicable where land and water (seawater, brackish) resources, not readily utilized by agriculture, are available.