Richardson (2011) has demonstrated the importance of the selection of algal species on the environmental impact of the biodiesel process. Factors to consider include the specie’s ability to scavenge light and CO2, growth rate, lipid content, cell size, cell wall strength, digestibility, ability to settle without flocculation, as well as the nitrogen content of the biomass. The combination of these influences the volume of the process, the relative recovery of biodiesel to biogas, the selection of downstream processing equipment, and the need to pretreat the algae prior to fermentation or digestion.