Algal Research · 2013 · 292 citations · 46 references
Microalgae are promoted as the next frontier of green biotechnology and are widely viewed as promising feedstocks for biofuels. The study seeks alternative strategies to overcome the major cost barriers that hinder algal biofuels from reaching their full potential. Using conservative assumptions of 15 g m⁻² d⁻¹ growth and 25 % lipid content, the authors modeled a pond‑to‑pump lifecycle for 1000 bbl d⁻¹ crude algae oil, requiring 4875 ha of raceway ponds and 1463 MLD water, and performed a techno‑economic analysis of 6000 modular 0.8 ha paddlewheel ponds in New Mexico that revealed cost barriers and resource challenges such as nutrients and water. The analysis shows that 10‑ and 20‑year capital return scenarios yield algal oil costs of $4.10 L⁻¹ ($15.52 gal⁻¹) and $3.21 L⁻¹ ($12.14 gal⁻¹), respectively, with extraction efficiency and lipid content as key cost drivers, a baseline EROI of 2.73, and significant sensitivity of EROI and operating costs to paddlewheel energy, water supply, and circulation.
Microalgae have been promoted as the next frontier of green biotechnology and gained widespread attention as desirable feedstocks for biofuels. Using conservative assumptions for microalgal growth rates (15 g m− 2 d− 1) and total lipid content (25%), the entire "pond-to-pump" lifecycle of algal biofuels for 1000 bbl d− 1 of crude algae oil production is modeled with approximately 4875 ha of raceway ponds for solar collection and cultivation and 1463 MLD (385 MGD) of water handling capacity in the current analysis. Technoeconomic analysis based on an array of 6000 modular 0.8 ha (2 acre) paddlewheel-driven ponds in New Mexico identified several cost barriers and resources challenges (i.e., nutrient and water resources). For 10- and 20-year capital return scenarios, the cost of algal oil production – $4.10 L− 1 ($15.52 gal− 1) and $3.21 L− 1 ($12.14 gal− 1), respectively – requires substantial capital and facility maintenance investments with principal cost sensitivities attributed to extraction efficiency and lipid content. Baseline conditions result in an energy return on investment (EROI) of 2.73. Uncertainty in energy requirements for paddlewheels as well as water supply and circulation significantly affect the EROI and operating costs. Alternative strategies to address the major cost barriers are needed for algal biofuels to realize their full potential.
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