Theoretical Maximum Algal Oil Production

TLDR

Algae are increasingly viewed as a promising biofuel feedstock because they can produce lipids at rates far exceeding those of conventional agriculture, yet commercial‑scale production metrics remain largely unknown. This study aims to determine the theoretical upper bound of algal oil production to inform industry design limits. The authors derive an absolute maximum using physical laws and perfect‑efficiency assumptions, and also calculate optimistic best‑case yields for six global sites under realistic efficiencies. The theoretical ceiling is 354,000 L ha⁻¹ yr⁻¹, while realistic best‑case yields range from 40,700 to 53,200 L ha⁻¹ yr⁻¹.

Abstract

Interest in algae as a feedstock for biofuel production has risen in recent years, due to projections that algae can produce lipids (oil) at a rate significantly higher than agriculture-based feedstocks. Current research and development of enclosed photobioreactors for commercial-scale algal oil production is directed towards pushing the upper limit of productivity beyond that of open ponds. So far, most of this development is in a prototype stage, so working production metrics for a commercial-scale algal biofuel system are still unknown, and projections are largely based on small-scale experimental data. Given this research climate, a methodical analysis of a maximum algal oil production rate from a theoretical perspective will be useful to the emerging industry for understanding the upper limits that will bound the production capabilities of new designs. This paper presents a theoretical approach to calculating an absolute upper limit to algal production based on physical laws and assumptions of perfect efficiencies. In addition, it presents a best case approach that represents an optimistic target for production based on realistic efficiencies and is calculated for six global sites. The theoretical maximum was found to be 354,000 L·ha−1·year−1 (38,000 gal·ac−1·year−1) of unrefined oil, while the best cases examined in this report range from 40,700–53,200 L·ha−1·year−1 (4,350–5,700 gal·ac−1·year−1) of unrefined oil.