The Algal Biomass Organization (ABO), the trade association for the algae industry, challenged the findings of a paper published 19 January in Environmental Science and Technology by researchers at the University of Virginia which determined, among other things, that “conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions and water.” (Earlier post.)
ABO said that the report was based upon obsolete data and “grossly outdated” business models, and overlooked tremendous improvements in technology and processes across the production cycle. Among the concerns of ABO about the report are:
Assumptions about algae growth systems. The report uses a first-generation, raceway-style pond system as its benchmark. Many leading algae companies abandoned that approach years ago and have a variety of more advanced cultivation systems, some of which are unrelated to the methods the authors sought to assess.
Assumptions about co-location. By assuming the production facility is not co-located with a large CO2 emitter, calculations for sourcing CO2 are flawed, resulting in a higher attribution of CO2 for algae plants. Most commercial-scale algae projects are being developed alongside major emitters in order to beneficially reuse CO2 that will take the place of equivalent carbon emissions from petroleum fuels.>
Assumptions about water use. The study assumes fresh water and non-potable salt water are equal. A sustainable industrial algae production model uses non-potable, non-agricultural water in the process of making liquid fuels.
Assumptions about nutrient use. Because the report does not look at the full algae fuel cycle, it ignored the opportunity to consider the ability of algae producers to recycle nutrients and avoid such a substantial burden.
Assumptions about energy use. Because the authors admittedly did not consider the full algae fuel cycle, which allows energy reuse through biodigester biogas combustion coupled with the carbon recycling from all of the aspects of biodigestion, the report errantly gives a higher emissions burden.
Assumptions about purchase of CO2 and fertilizer. The base case assumes algae farmers will purchase CO2 and fertilizer, yet such an approach is so prohibitively expensive it would never happen in reality.
The stochastic approach. ABO believes the results of any stochastic study should not be given the same weight as studies and analyses based measurable data.
Even with the scientific shortcomings of the survey, it shows that with a few improvements, algae is much better than terrestrial plants as a fuel source. The truth is that the algae industry is already well beyond the obvious improvements these authors suggest, and as we add these new efficiencies algae will become much more environmentally beneficial.
—Dr. Stephen Mayfield, director of the San Diego Center for Algae Biotechnology