ARPA-E is an attempt by the Energy Department to replicate for renewable energy what DARPA did for computing and digital technologies:
In previous decades, the Department of Energy drove basic research by operating giant government-funded labs, but under the leadership of Energy Secretary and Nobel Laureate Steven Chu, the agency has transformed itself into something different: the biggest, greenest venture capital firm in the world.
After receiving an unprecedented surge in funding for renewable energy courtesy of the American Recovery and Reinvestment Act, Chu set to work hiring big names from the nation's top research laboratories, in order to staff a new agency called ARPA-E, modeled after DARPA, the R&D wing of the Pentagon. In just three years, ARPA-E has made more than 180 investments in basic research projects in renewable energy, and that's in addition to grants issued by the Department of Energy proper, like the one that funded the Ocean Power Technologies project in Oregon.