While a debate rages about the government's role in funding energy innovation, sparked by high-profile failures of government-backed companies such as Solyndra and A123 Systems, a less controversial federal clean-tech investment strategy has been quietly humming along, garnering bipartisan support. So-called innovation hubs, multidisciplinary research centers meant to emulate the legendary Bell Laboratories by combining scientific research with applied technology, have managed to get continued government funding even as Congress works to cut the overall federal budget.