Uncertainty analysis and stochastic studies of techno-economics of algal carbon sequestration at Indian coal powered plants

Abstract

Formidable increase in atmospheric carbon dioxide (CO2) levels and the economic and environmental unfeasibility of the existing industrial carbon capture technologies have diverted the focus towards microalgae which can trap CO2, grow and, are processed into value-added products. Despite the enormous potential, the real-time adoption of algae-based industrial carbon capture is still lacking due to the uncertain economics and resource feasibility. Most studies done so far have analysed the economical aspect of microalgal carbon sequestration under varying concentrations of CO2 and not the percentage of emitted flue gas to be captured. To provide a better insight into the magnitude of scalability of microalgae-based industrial carbon capture the present study aims to evaluate the economic feasibility of capturing 1%, 10%, and 100% of the emitted industrial flue gas. Economic feasibility concerning the product to be harnessed and the uncertainties and risks linked with the input and output cost variables were analysed Algal productivity data obtained from the site-specific biophysical model was used as the input for techno-economic analysis and process simulation in SuperPro Designer® to produce 1 metric tonne of algal biomass as functional unit. Economic analysis revealed the decline in operating costs with decrease in the load of the emitted flue gas. 10% of the emitted flue gas capture scenario was considered favourable in terms of the 75% gross profit margin and lowest payback time (0.93 years). Capture of 1% of the emitted flue gas, reduced the operating expenditure, but, revenues generated are not sufficient enough for the process feasibility. Further, algal biorefinery scenarios were considered more feasible than a single product exploration. Uncertainty analysis showed 75% chances for profitability with variation in operating and capital expenses along with alteration in revenues. Such studies aid in real-time implementation of algae-based industrial carbon capture technologies.