Among the National Renewable Energy Laboratory’s (NREL) many funding agencies, the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) funds what is perhaps some of NREL’s most innovative work. ARPA-E’s mission is to advance promising technologies that are not yet ready for private-sector investment, with the goal of developing new ways to generate, store, and use energy. The high-risk, high-reward nature of these projects is what makes them s...