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Algae Life Cycle Study Challenged

February 5th, 2010 · 2 Comments

The Algal Biomass Organization (ABO) has questioned the algae life cycle study challenged saying it is based on obsolete data and faulty assumptions.

The trade organization representing the algae industry, Algal Biomass Organization (ABO), has issued a statement putting into question the results of a recent study on algae life cycle.

Unsustainable greenhouse emissions

The study, Environmental Life Cycle Comparison of Algae to Other Bioenergy Feedstocks, was recently published on the journal Environmental Science and Technology. Researchers from the University of Virginia, examining the lifecycle of algae biofuels, reached the conclusion that algae biofuels actually produce more greenhouse gases than what they sequester because of the energy-intensive process in which algae is grown. Algae production often require large amounts of fertilizers and CO2. The fertilizers are produced from petroleum-based materials.

The study was conducted to asses the actual environmental impact of algae biofuel lifecycle (including production) in comparison with land-based sources of biofuels like switchgrass, canola, and corn. The researchers recommended the use of flue gas and waste water from sewage treatment facilities to provide the algae with nutrients like nitrogen and phosphorus to reduce the demand for CO2 and oil-based fertilizers.

Obsolete Data and Faulty Assumptions

In their statement, the Algal Biomass Organization (ABO) directly challenged the conclusions and the methods used by the University of Virginia researchers. They maintain that the study is based on “obsolete data” and that the industry has already already surpassed technologically the measures and practices being recommended by the researchers.

Here are the main concerns raised by ABO, about the report:

* 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, ignored is 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. Yet those inputs are the major drivers of the negative impacts in the study.

“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,” said Dr. Stephen Mayfield, director of the San Diego Center for Algae Biotechnology. “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.”

I’m a huge fan of algae as a source of alternative fuel, and when the study came out last month, it felt like some kind of a personal blow.

The industry is in its infancy, and I’m glad that studies like this, from well-respected scientific sources, are coming out about the efficiency or sustainability of algae as a biomass source. I’m also glad that opposing scientific voices represented by the ABO are heard – an open, science-based discussion of these issues, by qualified people, is always necessary to improve the technology.

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Tags: Clean Technology

2 responses so far ↓

  • 1 Greg Wheeler // Feb 10, 2010 at 2:05 am

    The Environmental Science and Technology journal is an American Chemical Society publication. I don’t know about you, but I don’t put much faith in an organization that’s squarely opposed to open access to scientific information.

  • 2 James Baker // Feb 28, 2010 at 12:49 pm

    I’ve been quite excited by the potential for algae based alternative fuels for a while , everside I heard Exxon was making a big bet on it. I was somewhat taken in by the reports attacking its green credentials as a technology but your post has renewed my faith in its potential. Thanks.