Techno-economic analysis of microalgal biofuel production coupled with sugarcane processing factories

Due to several important characteristics of microalgae including high oil content, ability to overcome harsh conditions and high photosynthetic efficiency the production of biofuels from microalgal biomass has gained interest. The present study focused on economic evaluation of a microalgal biofuel production conceptually coupled with an actual sugar factory so that the waste effluent and byproducts from the factory would be used as inexpensive sources of nutrients and carbon dioxide. This study was based on the findings of a previous study in which the outputs and energy requirements of a conceptual microalgal biofuel production coupled with an actual sugar factory were evaluated. The economic feasibility of the process was performed using discounted cash flow analysis approach. Defined value internal rate of return (IRR) and a net positive value (NPV) were used as cost indicators. The sensitivity of the minimum biodiesel selling price (MBSP) to changes of some selected parameters was also investigated. It was found that in order for the biodiesel from microalgae to be competitive with the world petroleum price ($1.09/L) its estimated minimum selling price ($2.17) needs to be reduced at least by half. Sensitivity analysis on the MBSP illustrates that oil content of the microalgae, nitrogen content in the waste effluents, extraction and esterification efficiencies are important parameters which significantly affect the feasibility of the process. The microalgae is the most important parameter that as it varies from 20 to 40% (wt.%) the MBSP decreases from 3.03 to $1.74 per liter of biodiesel. This study examined economic viability of coupling microalgae biomass production with sugar factory wastes and by-products, and is significant to identify future research focus areas.