Through photosynthesis, algae can produce oil. In turn, algae-based biofuel can be used as an alternative to petroleum-based fuels. Fuels derived from algae are an attractive alternative energy source, because unlike petroleum-based fuels, which add trapped carbon dioxide into the atmosphere following combustion, biofuels do not.

However, research suggests that algae-based biofuels have several hurdles to overcome before becoming practical on a commercial scale. For example, proponents of algae-based biofuel argue that this type of biofuel produces less greenhouse gases, but recent research suggests otherwise. From The New York Times:

Proponents of algae oil say that the technology will perform significantly better than older generations of biofuels — that it will produce less greenhouse gas in its lifecycle, that it uses less land, that it can be grown anywhere — bypassing the concerns about competition with food crops that have come to plague corn ethanol.

Some environmentalists say water availability could be a problem for algae to fuel in the desert, though they say the issue has not been explored in depth. But some algae-to-fuel companies are already looking at using saltwater or wastewater — from sources like the Salton Sea — so that they won’t be shipping water to the desert.

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Unexpected problems include other algae or microorganisms — borne by the winds or the birds — eating or outcompeting the cultivated algae (“equivalents of weeds,” Melnick says). Temperature fluctuations could range high. There could be too much sun. “All the variables that farmers are constantly exposed to,” Melnick says.

So going from the lab to the field, some strains live and others die. Demattia can brace for some forces — for example, hold off on adding water when he expects rain — and adjust for others, such as through tweaking fertilizer amounts. But some things he cannot help.

“Algae’s a mystery,” Demattia said. “It dies on you, you never know why it died. You just have it die overnight, and you’ll come in and no one will know, even the guys who’ve been doing it for 30 years won’t know what killed it. So there’s still a lot more to learn.”

Algae-to-fuel technology can be carbon and energy intensive. More from Yale Environment 360:

Growing algae for biofuels is an energy-intensive process that can generate more greenhouse gases than the process sequesters, according to a new study. Examining the life cycle of algal biofuels, researchers from the University of Virginia found that the process emits high levels of greenhouse gases because algal production requires using large amounts of fertilizer. Those fertilizers often come from petroleum-based sources, and fertilizers also emit nitrous oxide, a greenhouse gas, according to the study. The study, published in the journal Environmental Science and Technology, said that while biofuel production from crops such as corn, canola, and switchgrass can result in a net carbon dioxide uptake, that is not yet the case with algal biofuels. The paper said that one promising way to overcome the environmental impact of using fertilizers to grow algal biofuels is to produce them with effluent from sewage treatment plants. Proponents of algal biofuels also said it is too early to make firm conclusions about the environmental impact of the technology because it is still in its infancy.

Algae biofuel companies respond to the study in the journal Environmental Science and Technology. From the New York Times:

One industry member said that while the University of Virginia research was conducted in a sound fashion, it was extremely outdated.

“It’s absolutely right if you think of it as last generation algae,” said Riggs Eckelberry, chief executive of the algae biofuel company Origin Oil, based in New Jersey. “But we’ve got to make this stuff viable now.”

One of the challenges to large-scale algae production noted by the paper was the need for large amounts of fertilizer to be added to the water in which it is grown. But Mr. Eckelberry said his company plans to use wastewater in algae production.

“Identifying wastewater is a homerun for algae production, probably the best there is,” he said. “There are lots of nitrates, and algae love dirty water — they can remove toxins, such as medical drugs from that water.”

In response, Andres Clarens the lead author of the study said he used the most recent data that he could, which was about 10 years old. Algae biofuel companies keep their research a closely guarded secret, he said.

He invited companies to share any more recent and relevant data they had with him.

“Everybody talks about the next generation – what is the next generation?” he said. “I’d be happy to model it if somebody produces it.”

He may get what he wishes for – the whole blow-out may result in a partnership.

On Tuesday, Mary Rosenthal of the Algal Biomass Association called him, and if member companies agree to make data available, Dr. Clarens may do a follow-up study.

One project is recycling dairy waste to produce algae-based fuel. From Sandia National Laboratories:

Recently Williams and other Sandia researchers have grown green algae in a 12-by-30-foot greenhouse using a simulated dairy effluent, the nutrient-rich liquid remaining after bacterial digestion of dairy manure. The solids from the digestion of dairy manure can potentially be used to develop fertilizer and feed and the liquid serves as a nutrient source for algae. The algae are typically cultured for several days, followed by harvesting and dewatering, after which the algal oil is extracted. The algae produce lipids, the most useful being neutral oil made up largely of triacyglycerides (TAG) that can be converted to biofuels.

Williams said that growing algae for biofuels eliminates many problems associated with traditional biofuels.

“The current generation of biofuels [starch- and sugar-based ethanol and oil crop-based biodiesel] rely on the use of commodity crops and therefore compete for use of food crops, primarily corn,” she said. “Also, they are very farm-intensive and use a lot of good farming land, fuel and fertilizer inputs and fresh water.”

Algae ponds, on the other hand, can be put on marginal land and grown with non-fresh brackish water produced from energy mineral extraction (petroleum, natural gas, coal-bed methane), or nutrient-loaded wastewater from municipal and agricultural sources. The Southwest has the potential for being a leader in manufacturing this new type of biofuel because “it has lots of barren land that can’t be used for anything else, lots of sunlight and a lot of marginal water,” Sandia researcher Brian Dwyer said.

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Williams anticipates that the Sandia research will have the potential to provide new jobs and economic development to New Mexico, the seventh largest dairy-producing state in the nation. The state’s dairy industry employs more than 5,000 people and has an annual impact of nearly $2.7 billion.

The 340,000 dairy cows in New Mexico produce large quantities of manure and nutrient-rich effluent water that represent a significant waste management problem and regulatory expense to the state’s dairy industry. These and other agri-industrial waste streams represent a valuable and underused feedstock for recycling of energy, biofuels, reusable water and other coproducts. The DOE Algal Biofuels Technology Roadmap currently in draft suggests the use of non-fresh water sources, including agricultural effluent, for algal biomass production. Besides providing a source of non-fresh water and the recycling of needed nutrients, the use of these waste streams in an integrated biorefinery will help to alleviate disposal regulatory requirements on dairies and other confined animal feeding operations in New Mexico and the broader United States.

Images via Randy Montoya

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