Production cost of a real microalgae production plant and strategies to reduce it

The cost analysis of a real facility for the production of high value microalgae biomass is presented. The facility is based on ten 3 m³ tubular photobioreactors operated in continuous mode for 2 years, data of Scenedesmus almeriensis productivity but also of nutrients and power consumption from this facility being used. The yield of the facility was close to maximum expected for the location of Almería, the annual production capacity being 3.8 t/year (90 t/ha·year) and the photosynthetic efficiency being 3.6%. The production cost was 69 €/kg. Economic analysis shows that labor and depreciation are the major factors contributing to this cost. Simplification of the technology and scale-up to a production capacity of 200 t/year allows to reduce the production cost up to 12.6 €/kg. Moreover, to reduce the microalgae production cost to approaches the energy or commodities markets it is necessary to reduce the photobioreactor cost (by simplifying its design or materials used), use waste water and flue gases, and reduce the power consumption and labor required for the production step. It can be concluded that although it has been reported that production of biofuels from microalgae is relatively close to being economically feasible, data here reported demonstrated that to achieve it by using the current production technologies, it is necessary to substantially reduce their costs and to operate them near their optimum values.