Publication Details

Title : Greenhouse Gas Emissions, Energy and Water Use of Photobioreactors for Algal Cultivation and Biofuels Production
Publication Date : June 30, 2017
Authors : Q. Li, C. Canter
Abstract : The Department of Energy’s Bioenergy Technology Office (BETO) collaborates with a wide range of institutions towards the development and deployment of biofuels and bioproducts (DOE BETO 2016). To facilitate this effort, BETO and its partner national laboratories develop detailed techno-economic assessments (TEA) of biofuel production technologies. The National Renewable Energy Laboratory (NREL) recently completed an algal cultivation photobioreactor (PBR) study as part of an internal BETO milestone (Davis et al., 2017, the PBR study henceforth), which used a techno-economic analysis (TEA) to estimate the minimum biomass-selling price (MBSP) of algae biomass at the farm gate. The biomass cost projections considered the design and operation of a culture inoculum system, biomass production, CO2 storage and delivery, onsite circulation of cultures and clarified water, makeup water delivery, and biomass dewatering.
The goal of this analysis is to expand the GREET model and determine greenhouse gas (GHG) emissions, fossil energy consumption, and water use from the algal biomass production and dewatering operations as modeled in the PBR study. To obtain the well-to-wheel (WTW) life-cycle GHG emissions, energy and water use from PBR study (biomass production and dewatering) were added to the combined algae process (CAP). CAP produces renewable diesel and naphtha from lipids, ethanol from sugars, and heat-power-nutrient recycles from anaerobic digestion of the protein residue (Frank et al. 2016).

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