Comprehensive Evaluation of Algal Biofuel Production: Experimental and Target Results

Abstract

Worldwide, algal biofuel research and development efforts have focused on increasing the competitiveness of algal biofuels by increasing the energy and financial return on investments, reducing water intensity and resource requirements, and increasing algal productivity. In this study, analyses are presented in each of these areas—costs, resource needs, and productivity—for two cases: (1) an <em>Experimental Case</em>, using mostly measured data for a lab-scale system, and (2) a theorized <em>Highly Productive Case </em>that represents an optimized commercial-scale production system, albeit one that relies on full-price water, nutrients, and carbon dioxide. For both cases, the analysis described herein concludes that the energy and financial return on investments are less than 1, the water intensity is greater than that for conventional fuels, and the amounts of required resources at a meaningful scale of production amount to significant fractions of current consumption (e.g., nitrogen). The analysis and presentation of results highlight critical areas for advancement and innovation that must occur for sustainable and profitable algal biofuel production can occur at a scale that yields significant petroleum displacement. To this end, targets for energy consumption, production cost, water consumption, and nutrient consumption are presented that would promote sustainable algal biofuel production. Furthermore, this work demonstrates a procedure and method by which subsequent advances in technology and biotechnology can be framed to track progress.

Keywords

• algae
• &lt;strong&gt; &lt;/strong&gt;biofuel
• energy return on investment
• financial return on investment
• water intensity
• resource constraints
• biodiesel
• renewable diesel
• biogas