Algae's Water Problem

Over the years, the pans and raves about algae-based biofuels have certainly been memorable. A number of scowling negative reviews would have done American Idol’s Simon Cowell proud. Conversely, some promotional claims appear to have come directly out of the Marvel Cinematic Universe where, one gathers, the Laws of Thermodynamics have been conveniently suspended.

Enter the National Research Council.

In 2012, the NRC, part of the  National Academy of Sciences, released a report on whether U.S. development of algae-based biofuel is sustainable.

The report was commissioned by the Department of Energy to dispassionately wade through the thickets of rhetoric, hype, flim-flam, pettifoggery and general humbug offered up in the promotion and criticism of algae.

So, what is algae’s grade - pass, fail, or incomplete? Overall, algae earned an “incomplete.” As one would expect, in its key finding, the NRC concluded that it was not possible to sustainably produce 10 billion gallons of algae biofuels today.

“Algal biofuels are not quite ready for primetime,” said NRC co-author Joel Cuello of the University of Arizona in a prepared statement. “To produce 10 billion gallons of biofuel, you’d need about 33 billion gallons of water. That is a huge concern.”

The report does sound a hopeful note, however. According to the NRC, “The committee does not consider any one of these sustainability concerns a definitive barrier to sustainable development of algal biofuels because mitigation strategies for each of those concerns have been proposed and are being developed.”

The strategies under development today include the use  of salt-water (or brackish) algae biofuels and heterotrophic algae (algae that can grow in the dark). These are precisely the paths taken by all six industry giants — Solazyme, DSM-Martek, Algenol, Aurora Algae, Live Fuels, and Sapphire Energy. In fact, all six companies came to many of the same conclusions as the NRC report, years ago.

So did Dr. Nigel Quinn and colleagues at the Lawrence Berkeley National Laboratory and the Energy Biosciences Institute at UC Berkeley. Their 2010 analysis, sponsored by EBI, concluded that it was not cost-effective to produce microalgae biofuels without major advances in technology.

According to a UC San Diego release, the NRC report also suggested that algae biofuels might be limited by fresh water because no published research study had demonstrated the feasibility of using engineered marine species of algae. But this November, scientists genetically engineered marine algae and demonstrated that saltwater algae – like freshwater algae -- can produce enzymes key to biofuel production. 

“What this means is that you can use ocean water to grow the algae that will be used to produce biofuels,” Stephen Mayfield, a professor of biology at UC San Diego, told reporters. “And once you can use ocean water, you are no longer limited by the constraints associated with fresh water. Ocean water is simply not a limited resource on this planet.”

A hard look at sustainability issues

No matter what position you take on algal biofuels, there’s definite value in the report’s pages – and, overall, in the consideration of sustainability in algae.  There are five areas of “major” sustainability concern as raised in the NRC report. They are water, nutrients, land use, return on energy investment, and greenhouse gas emissions over the lifecycle of algal biofuels.

Let’s compare how the NRC looks at identified concerns with how the algae industry views them (courtesy of the Algae Biomass Organization).

 

The bottom line

NRC spokespeople have repeatedly said their conclusions are not a “show stopper” for algal biofuels.

"Faced with today's technology, to scale up any more is going to put really big demands on ... not only energy input, but water, land and the nutrients you need, like carbon dioxide, nitrate and phosphate," Jennie Hunter-Cevera, a microbial physiologist who headed the committee that wrote the report, told Reuters.  "Algal biofuels is still a teenager that needs to be developed and nurtured.”

And nurturing is exactly what the algae biomass association is aiming to do.

"With more than 150 companies and more than 60 labs and research facilities continuing to innovate the industry, and with pre-commercial facilities coming online in 2013, there’s no doubt that algal fuels will only become more economically and environmentally sustainable,” insists the ABO. “And researchers will have more current and accurate data sets from which to make projections.”

Hopefully, these data sets will include a number of areas concerning sustainable algae biofuels were left out of the report.

Heat is one such challenge. Closed systems generate a lot of it, and by most reports the engineers are having a tough time dissipating the heat before it kills off the algae, thus shortening the growth cycle. This poses a greater overall threat to No-Kill systems such as Algenol’s, which derive their superior economics from keeping algae alive for longer periods, but it remains a concern overall.

The other? Defense against predators. To make algae biofuels sustainable, the tiny plant-like organisms have to produce fuel before getting gobbled. You’d be surprised how many micro-critters love nothing more than a feast of algae. Defending algae against predators like rotifers, bacteria, and ciliates is an unfinished task across all open systems where microbial pests, viruses, predators and competitors can emerge.

Which makes the interesting point that one of the keys to exploiting algae as a feedstock for energy is the important task of protecting it. OriginOil has filed a patent application for Algae Screen, a process that uses electromagnetic energy to target invaders. Such protection is a highly sustainable farmer’s way to look at the world – defend thy crop with all you have, and you may have a resource to sustain you.

Depending on how industry deals with sustainability issues, biofuels from algae could be an important part of our future renewable fuel system. The next decade will be the real test as to whether the technology falls victim to the naysayers or emerges as a real contender.

 

 

 

 

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