Algal biofuel production for fuels and feed in a 100-ha facility: A comprehensive techno-economic analysis and life cycle assessment

Abstract

This techno-economic analysis/life-cycle assessment is based on actual production by the Cornell Marine Algal Biofuels Consortium with biomass productivity > 23 g/m 2-d. Ten distinct cases are presented for two locations, Texas and Hawaii, based on a 100-ha production facility with end-to-end processing that yields fungible co-products including biocrude, animal feed, and ethanol. Several processing technologies were evaluated: centrifugation and solvent extraction (POS Biosciences), thermochemical conversion (Valicor), hydrothermal liquefaction (PNNL), catalytic hydrothermal gasification (Genifuel), combined heat and power, wet extraction (OpenAlgae), and fermentation. The facility design was optimized by co-location with waste CO 2 , a terraced design for gravity flow, using renewable energy, and low cost materials. The case studies are used to determine the impact of design choices on the energy return on investment, minimum fuel and feed sale prices, discounted payback period, as well as water depletion potential, human health, ecosystem quality, non-renewable resources, and climate change environmental indicators. The most promising cases would be economically competitive at market prices around $2/L for crude oil, while also providing major environmental benefits and freshwater savings. As global demands for fuels and protein continue rising, these results are important steps towards economical and environmentally sustainable production at an industrial scale.

Lipid content in microalgae determines the quality of biocrude and Energy Return On Investment of hydrothermal liquefaction

“…Lab-scale [12][13][14][15][16][17][18] and pilot-scale [19][20][21] HTL studies using various microalgal strains have produced biocrude yields around 30-50% (dry cell weight basis) regardless of the biochemical composition of microalgae (biomass-agnostic). Since HTL directly treats wet biomass without drying, the entire production chain of microalgal biofuels can be improved in terms of energy balance, economic viability, and environmental impact [22,23]. HTL is therefore gathered considerable attention as a promising unit process for microalgae-based biofuel production.…”

Microalgae biorefineries: The Brazilian scenario in perspective

“…The extracted algal mass is then phase separated and lipids are recovered from the nonpolar solvent by distillation [97]. The economic viability of using only the lipidic fraction for the production of biofuels while converting the LEA fraction into other products (i.e: fertilizers and animal feed) is controversial though [19,45,46]. Furthermore, the use of wastewater for cultivating microalgae might render algal biomass unsuitable for the production of animal feed or food supplements.…”

Prospects for commercial production of diatoms

“…Nevertheless, we did want to provide the reader with some information that is at least available for other microalgae in hopes that this might be helpful. For example, there are several recent cost analyses, including those for (a) a 100-ha algal biofuels facility [88]; (b) algal techno-economic, life cycle, and resource assessment (a modeling study) [89]; and (c) biomass pretreatment [90]. Furthermore, there are recent NREL reports on the economics of algal biomass production [91] and the conversion of algal biomass to biofuels [92].…”