Dynamic process model and economic analysis of microalgae cultivation in flat panel photobioreactors

Microalgae are often considered an important renewable feedstock for production of bio-energy and value-added products and have the potential to help meet the rising demands of energy, food and feed in the world. To determine microalgae productivity in outdoor commercial scale flat panel photobioreactors for a given algal species and any given location, a first-principles based quantitative growth model was developed taking into account geospatial variabilities. Based on local climatic factors, which included solar irradiance, air temperature, relative humidity and wind velocity, a combined heat and mass transfer model was developed to predict temperature of the culture medium where microalgae was cultivated. The temperature data was further incorporated into a biological growth kinetics model for a given algal species to predict microalgae productivity potential for that location. Yearly microalgae productivity ranged between 3800 and 13,000 t km−2 year−1 for the different locations examined. A detailed economic analysis was conducted to assess microalgae cost for the locations. Based on the economic analysis, microalgae production cost for in flat panel photobioreactor systems ranged between 2895 $ t−1 to 9564 $ t−1. The robust techno-economic analysis demonstrates that microalgae production costs depend significantly on geospatial location, microalgae productivity potential as well as engineering and process parameters of algae cultivation.