The Arlington, Va. clean tech startup, OPower, closed a $50 million series C investment led by Accel Partners and Kleiner Perkins Caulfield & Byers (KPCB) and joined by the company's earlier investors New Enterprise Associates (NEA) the firms announced Monday. OPower's software-as-a-service helps electric and gas utilities understand who their residential energy consumers are, and how they are using power. Home owners get access to OPower programs through their utilities. OPower's applications let them see if they're more or less energy-hogging than their neighbors, allow them to set personal goals to reduce their own energy consumption at home, and receive alerts if they're headed for a large bill at the end of the month among other things that are meant to inspire a behavior change.