There are lots of creative ways to produce biofuel from algae, but NASA's takes the cake. The space agency is growing biofuel in plastic bags of sewage floating in the sea. The Offshore Membrane Enclosures for Growing Algae (OMEGA) bags are based on technology used to recycle astronauts' wastewater. The bags allow freshwater to exit and also keep saltwater out.
NASA's biofuel process works by filling semipermeable OMEGA bags with sewage and algae. The algae eat nutrients in the sewage, clean up the water, and produce lipids for fuel with help from water, solar energy, and CO2. At the end of the process, oxygen and fresh water are released from the bags.
As with other methods of algae-based biofuel production, there are still hurdles to overcome. NASA is hunting for a plastic bag that can withstand freezing ocean temperatures and intense waves without becoming brittle, for example. Still, NASA plans on building a demonstration project by 2010.
The technology is almost cost-competitive with land-based methods for algae biofuel production, but with the added benefit that OMEGA projects don't displace agriculture or have to pay taxes. NASA estimates that 10 acres of ocean could produce 21 billion gallons of biofuel each year--enough for all U.S. aviation needs. A number of airlines have already begun to test out biofuels, including Continental Airlines, Virgin Atlantic, and Air New Zealand.
[Via Scientific American]