As reported yesterday in ScienceDaily here,
With many companies investing heavily in algae-based biofuels, researchers from the University of Virginia’s Department of Civil and Environmental Engineering have found there are significant environmental hurdles to overcome before fuel production ramps up.
The ScienceDaily article summarizes some aspects of a paper by Clarens, et al., “Environmental Life Cycle Comparisonof Algae to Other Bioenergy Feedstocks,” published in the most recent edition of the journal, Environmental Science and Technology.
I’ve been reading the paper. The authors use a statistical approach to leverage available data, while providing information for sensitivity analyses. The results indicate that current algae production methods produce more carbon dioxide than they remove from the atmosphere, unlike switchgrass, corn and canola, all of which were found to be net consumers of carbon dioxide. Reasons for this result include energy requirements for providing carbon dioxide for the algae, and energy requirements for producing fertilizer to feed algae.
The authors show that some negative aspects of algae production can be overcome by 1. siting algae factories near fossil-fuel power plants, using their carbon dioxide as an input, and 2. by growing algae at sewage treatment plants, using nitrogen and phosphorous in wastewater, eliminating the need for adding fertilizer while providing water for the algae, as well. They also note that biomass production from algae is in its infancy such that
significant improvements in algae cultivation could increase the favorability of energy production from algae over the next several decades.
They are not in a rush, it seems, but the authors are relatively young.
The authors also point out that their analysis does not include energy requirements (and associated carbon dioxide outputs) for processes following biomass production, such as extraction of lipids from algae and subsequent conversion to a usable fuel. They focus here on biomass production and “preliminary transportation,” such that a full life cycle analysis will likely be the subject of another paper or two or three.