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Biomass Alabama algae biofuel

Published on August 20th, 2014 | by Tina Casey

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Alabama Gets First-In-World Carbon-Negative Algae Biofuel

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August 20th, 2014 by  

Holy floating photobioreactors, Batman! With a little help from the Japanese corporation IHI, Alabama can now lay claim to the world’s first algae biofuel system that also treats municipal wastewater, resulting in a carbon-negative process. IHI’s Algae Systems LLC company has just completed a demo run on a 40,000 gallon-per-day plant that deploys floating photobioreactors in Mobile Bay at Daphne, Alabama.

That’s quite a step up from the test tube-sized algae biofuel experimentation going on at the Daphne Utilities treatment plant last fall. Aside from the carbon-negative angle, the system is particularly interesting because it relies on local, naturally occurring algae rather than those amped-up proprietary algae strains we’ve been fangirling on lately.

Alabama algae biofuel

Image (cropped): Courtesy of Algae Systems LLC.

Plenty Of Room In The Algae Biofuel Pot

If you’re a little skeptical of the naturally occurring strain thing, consider the parallel with solar power. While ultra-efficient solar cells are coming on the market, the most efficient solar cell does not necessarily lead to the most cost-effective solar installation, or to the broadest range of application.

Think about the contrast between relatively low-efficiency organic solar cells and their high-efficiency silicon cousins, and you’re on the right track.

Crossing that idea over to algae biofuel production, IHI and Algae Systems have taken a holistic, energy-efficient approach to algae biofuel production. While the new algae biofuel system might not boast the most efficient strains for biofuel production, it is a problem-solver that piggybacks on a liability — that would be the municipal wastewater — and extracts value from it.

The Alabama Algae Biofuel Photobioreactors

For those of you new to the topic, floating photobioreactor is algaespeak for plastic bag. What you do is you take long, durable plastic bags, fill them with a nutrient-rich growing medium (wastewater, in this case), throw in some algae, and let sunlight work its magic. The algae grow quickly in the closed environment, and there’s your biofuel crop.

The Daphne Utilities wastewater treatment plant chugs away at three million gallons per day, so there’s plenty of wastewater to spare for the new demo plant. That takes care of the water supply angle, which is something that bedevils conventional algae farming.

The choice of local algae means that up-front costs are nothing compared to developing a proprietary strain. It also provides for lower running costs, since the local algae are already acclimatized and require no special environmental controls. That also translates into lower energy use.

The cost and energy consumption angles also come into play with the choice of floating the photobioreactors out in the bay, rather than building new infrastructure on land. The bay waters help to stabilize the internal temperature, and the waves provide a natural means of keeping the contents mixed for optimal growing conditions.

As the algae grow, they take up the nutrients in the wastewater, which would otherwise require an energy intensive treatment process. That’s the carbon-negative deal in a nutshell. According to IHI, after the algae is harvested the result is clean water than can be discharged into the bay without risk of creating dead zones.

Not for nothing, but NASA is also tinkering around with a similar wastewater/algae photobioreactor system, with an eye toward recycling wastewater in space.

We’ve gone on and on (and on) (here’s another one) about the many ways in which human waste can be repurposed for energy production, so add algae biofuel production to the list.

From Algae To Biofuel

As for the conversion of algae to biofuel at the Daphne facility, that’s the proprietary part of the system, so we can’t tell you too much about that.

 

What we can tell you is that the system is based on a hydrothermal liquefaction process, which was promising enough to win new Energy Department funding to the tune of $3.2 million for further improvement as part of a $6 million advanced biofuel development package announced last month. The other part of the package went to a woody biomass project.

The $3.2 mil for algae biofuel goes to a research consortium led by SRI International and Algae Systems. As far as we can tell, one focus of the project will be to improve the fuel quality by reducing the nitrogen content of the feedstock.

This is where the marriage between IHI and Algae Systems comes in. Algae Systems is a start-up that boasts a five-year history dating back to 2009, but IHI got its start in 1853. The company has taken a deep dive into equipment supply for high tech systems in the thermal energy, nuclear power, and aerospace fields, so its areas of expertise dovetail with the hydrothermal liquefaction process.

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About the Author

Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • GCO

    a 40,000 gallon-per-day plant

    According to the linked article, this is the wastewater throughput. Knowing how much fuel is produced would be much more interesting IMHO — any idea?

  • Kevin McKinney

    And I don’t quite get how this is carbon-negative. Yes, the CO2 ingested by the algae comes from the atmosphere (somehow; see Deep Time’s comment). But doesn’t it just get released back to the atmosphere when the fuel is burned?

    OK, now I see where it says “As the algae grow, they take up the nutrients in the wastewater, which would otherwise require an energy intensive treatment process.” To be picky, though, that doesn’t seem like a true carbon-negative process; it’s a carbon-neutral process which displaces a carbon-positive one. Still a good thing, of course–!

    • Offgridman

      Processing your sewage or liquid waste as it is called here usually involves energy input in the form of pumps, stirrers, and filtration, with the resultant release of methane and some CO2 from the stand ponds. While this diagram is inaccurate in showing CO2 being drawn directly from the atmosphere I think this process can be carbon negative due to the energy not used in processing the sewage, what is caught by the algae, and that the process is encouraged by solar input rather than some other energy source, with the resultant fuel output that hasn’t needed to be processed by a high energy process like fossil fuels are.
      Just my guess.

      • Kevin McKinney

        Thanks–sounds reasonable enough.

        • Offgridman

          Glad to have been able to be of some help, and that you were able to understand my thoughts on this.

    • aphocus

      Any system generally runs at a loss (efficiency) so that could make it carbon negative, and also making of other crude products like plastics which aren’t being burt could help as well.

  • Deep Time

    I don’t get how the algae use atmospheric CO2 while being in sealed plastic bags. Does some mechanism somehow supply the bags with ambient air?

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