"Our main driver was to look at how much land would be available for installing large algae pond systems," said Dr. Erik Venteris, a spatial modeling engineer at the Pacific Northwest National Laboratory and the lead investigator of the study.Algae pond facilities require between 1,000 and 1,200 acres of land for one facility, said Venteris. The facilities he envisions would hold up to one million gallons of algae biodiesel per facility.Where the 14 percent of available land is located is a major concern, however, according to Dr. Richard Nelson, a professor in the Center for Sustainable Energy at Kansas State University. This number includes low-slope, non-protected land. Much of the desert land in Arizona and other parts of the southwest are flat and available, but the amount of infrastructure and resources available in these areas remains a question mark.Venteris's study took into account not only areas that were currently available with a low-slope, but also areas that would be cheap to purchase from their current owners."The first candidates that I think about are where we have agricultural land that is no longer productive," said Dr. Stephen Mayfield, the director of the University of California, San Diego's Algae Center for Biotechnology.Mayfield said there is tons of agricultural land sitting idle because it has been "salted out" of production. These unproductive lands would be more valuable holding algae facilities, and Mayfield cites California's Imperial Valley as a good site for algae ponds since its only current use is storing agricultural runoff, and algae can grow in both ocean and wastewater. However, lands in California have some of the highest prices of acquisition, according to Venteris's study.The cheapest land that Venteris found was the arid lands in the West, but two types of land stood out to him as good contenders for algae biofuel facilities: marginal croplands and southern woodlands.Marginal croplands, or lands that netted the least amount of profit, are useful because the owners have a high incentive to sell their land. Also, this land has been used for agriculture and should share similar climate and resource characteristics that would promote algae growth.Southern woodlands have relatively cheap wood, flat land, and plenty of water and soil resources, but backlash from environmental groups is a major concern with using these lands since it would require cutting down trees.Venteris emphasized the use of marginal croplands before woodlands, and Mayfield believes that woodlands should not be considered until other options have been exhausted. Mayfield believes that the algae facilities should first be constructed in places that already have the optimal climate conditions, resources, cost, and infrastructure. The U.S. has CO2 pipelines across the country, so Mayfield believes it would be "trivial" to build pipelines once algae-based fuels become more prominent.Finding a market for biodiesel is another issue. If algae-based transportation fuels were offered at service stations today, the cost would be quite expensive making it a less attractive option than petroleum fuels.Nelson said the current market for algae fuels exists in places that don't have a large gasoline market, and once a larger market is found, the algae fuel industry still has to find a way to partner with the petroleum industry so that it can sell its fuel.Despite the challenges, Mayfield remains optimistic."There was no petroleum industry in 1900," said Mayfield, "we needed energy, so we built it."Image: agrilifetoday on Flickr Follow Scientific American on Twitter @SciAm and @SciamBlogs. Visit ScientificAmerican.com for the latest in science, health and technology news.
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