Considerations for the Design of a Gas Transport System for Co-location of Microalgae Cultivation with CO 2 Sources
Co-locating microalgae cultivation facilities with sources of waste CO 2 may present opportunities for cost savings that could benefit the algal biomass industry and industries or utilities that have incentives to manage carbon emissions. However, the cost savings have not been quantified. We compare the cost of utilizing CO 2 from flue gas transported to 405-ha, base-case, open-pond microalgae facilities to the commercial purchase price of CO 2 . Sources of CO 2 include coal- and natural gas-fired power plants and ethanol, ammonia, and cement production plants in the United States. The transport of CO 2 -containing gases to the microalgae cultivation facility requires infrastructure and electricity. This engineering analysis explores the parameters that affect the infrastructure and transport distance over which emitted flue gases can be cost-effectively transported to microalgae cultivation facilities, compared to the cost of commercially purchased CO 2 (i.e., the break-even distance). Parameters that are varied include size of facility pond area, productivity, and daily duration of waste CO 2 emissions that are transported to algae. Under our assumptions and under all cases in this study, cost savings can be achieved by co-locating microalgae facilities near waste CO 2 sources. The break-even distance, which is estimated here to range from under 2 to 80 km, depends primarily on the concentration of CO 2 in flue gas, algae productivity, facility size, and pipeline system design considerations. Greater break-even distances are simulated if electricity cost is minimized, rather than if capital cost is minimized.