NASA has developed a system capable of growing large amounts of algae for biofuel production within a network of floating plastic bags, an innovation its developers say could ultimately produce a new fuel source. By pumping wastewater and carbon dioxide into four nine-meter plastic bags at a demonstration plant in California, researchers have shown that the system can grow enough algae to produce nearly 2,000 gallons of fuel per year under ideal conditions, according to a report in MIT’s Technology Review. If built near wastewater plants, the technology would overcome two of the challenges associated with large-scale algae biofarms — access to huge amounts of fertilizer and large areas of land. One significant challenge, however, is that the technology currently would require an enormous amount of plastic. For instance, a scenario capable of producing 2.4 million gallons of algae per year would also require five square kilometers of plastic bags, which would likely have to be replaced annually.