Abstract
Co-locating microalgae cultivation facilities with sources of waste CO2 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 CO2 from flue gas transported to 405-ha, base-case, open-pond microalgae facilities to the commercial purchase price of CO2. Sources of CO2 include coal- and natural gas-fired power plants and ethanol, ammonia, and cement production plants in the United States. The transport of CO2-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 CO2 (i.e., the break-even distance). Parameters that are varied include size of facility pond area, productivity, and daily duration of waste CO2 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 CO2 sources. The break-even distance, which is estimated here to range from under 2 to 80 km, depends primarily on the concentration of CO2 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.
