To assess a new energy technology before considering its implementation, it is essential to perform a life-cycle analysis on its total energy efficiency and environ­ment impact, including both its potential benefits and risks. A viable energy tech­nology should have a significant net energy gain or a carbon footprint reduction based on its objective life-cycle analysis. Chapter 30 reports the process economics and greenhouse gas audit for microalgal biodiesel production. Chapter 31 discusses the sustainability considerations about microalgae for biodiesel production while Chap. 32 reports a life-cycle assessment for algae-to-energy systems.