The DoE does a whole lot more than just "supply power" and "energy" research. It runs a large number of national laboratories including Brookehaven, Fermi Lab, Jefferson Lab, Oak Ridge, SLAC, etc. Many of these labs are not single focus and have research facilities ranging from biofuels to medicine. For example many cancer treatment technologies have originated from DoE labs, I would hope that most people here would agree that cancer research is important :)