Concerns of Low Importance
• Accidental releases of culture water and infiltration of nutrients and chemicals into soil or surrounding water.
• Seepage of culture water into the local groundwater system if clay-lined ponds are used or if plastic liners are breached through normal weathering or from extreme weather events.
• Potential presence of mosquitoes and mosquito-borne diseases around poorly managed open ponds.
source. If algal biofuels are to contribute a significant amount of fuels for transportation, the following are needed:
• Improvements in the algal strains used.
• Testing additional strains for desired characteristics.
• Advancements in the materials and methods used for algae cultivation and for processing algal biomass into fuels.
• Reductions in the energy requirements for cultivation, algae collection, and pro-cessing to fuels.
Algal strain development is needed to enhance traits that contribute to increasing fuel production per unit resource use, reducing the environmental effects per unit fuel produced, and enhancing economic viability. Improvements in biomass or product (lipid, alcohol, or hydrocarbons) yield, culture density, nutrient uptake, ease of harvest, and photosynthetic efficiency are some of the improvements that would improve sustainability of algal biofuels.
The strains used for large-scale algal biofuel production are being improved through selection and genetic approaches. Breakthroughs and innovations in areas such as increasing the capability of algae to use nutrients efficiently or engineering designs to reduce processing requirements have the potential to greatly improve the energy balance and enhance the overall sustainability of algal biofuels.
Engineering solutions to enhance algae cultivation, to facilitate biomass or product collection, and to improve processing of algae-derived fuels can increase the EROI and reduce the GHG emissions of algal biofuel production.
Lipid collection and conversion have dominated algal biofuel development for several decades. Processing improvements to reduce energy requirements and increase productivity continue to be proposed. Whole-cell processing of algae into fuels also has been investigated. Innovations focused on reducing energy use, nutrient requirements, water use, and land use are necessary for the sustainable development of algal biofuels. These innovations may require algal strain improvements, engineering solutions to improve hardware required for fuel production, and the interplay of the two.