Assessing the stability and techno-economic implications for wet storage of harvested microalgae to manage seasonal variability

Abstract

The MFSP of $3.40/GGE for this scenario is slightly less than the dry storage with rotary drum dryer scenario ($3.53/GGE), but considerably less than the most realistic dry storage scenario (contact drum dry storage scenario at $3.72/GGE). [...]overall this preliminary analysis indicates that wet storage appears to compare favorably to dry storage when all elements are evaluated consistently. Additionally, greater seasonal variability in algae productivity leads to greater storage requirements and costs, further increasing MFSP. [...]the results of this analysis further validate the conclusions of previous analyses [10] that emphasize the importance of improving winter productivity to the extent possible, either through strain rotation or other strategies (although recognizing it is not likely that winter productivity can ever be improved to match summer productivity, at least for outdoor cultivation systems in the USA, given the lower solar irradiation available in the winter months). [...]it should also be noted that wet algae storage research is in the nascent stages of development, and improvements are possible that may reduce losses and minimize composition changes. Subsequent NREL modeling efforts indicate targeting alternate coproducts from sugar, such as succinic acid rather than ethanol, may produce more favorable overall economic results as a means to ultimately reduce algae fuel costs to economically viable targets in the future [2]. [...]in this analysis, sugars are converted to succinic acid, while lipids are again converted to RDB, and protein is again sent to anaerobic digestion.