Ellen Williams is a distinguished university professor at the University of Maryland and the director of the university's Earth System Science Interdisciplinary Center. Ellen Williams earned her BS in 1976 from Michigan State University and her PhD in 1981 from the California Institute of Technology. Her research interests are in surface chemistry and nanotechnology. She founded the University of Maryland Materials Research Science and Engineering Center and served as its director from 1996 through 2009. She served as chief scientist at BP from 2010 to 2014, and as director of the U.S. Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) from 2014 until early 2017.