While it is possible to make carbon-based battery electrodes from biomass, the process is often costly and limited by availability of raw materials. In this case, the Boulder team's process is a little like beermaking itself, in that it requires the help of some beneficial fungus called Neurospora crassa that grows in the sugar-rich wastewater. Not only does the fungus clean the runoff, but it also creates "one of the most efficient naturally-derived lithium-ion battery electrodes known to date," according to Science Daily.

"The wastewater is ideal for our fungus to flourish in," graduate student and lead author Tyler Higgins said, "so we are happy to take it." While it's not the first beer-derived fuel cell we've seen, Huggins and his co-authors see a future in the beer-to-batteries business -- they've already filed a patent for the process and created a new company called Emergy to commercialize it. "We see large potential for scaling," Huggins said, "because there's nothing required in this process that isn't already available."