Heather Liddell, PhD, is a senior scientist at Energetics, a U.S. clean energy consultancy in Washington, DC (Email: hpliddell@energetics.com). She studies resource use and environmental impacts in manufacturing, focusing on the identification and development of technical strategies for improving the sustainability of the U.S. industrial sector. Core to this work is an integration of top-down strategies (e.g., supply chain modeling and sector-wide carbon and energy analysis) and bottom-up strategies (e.g., impact and feasibility assessments at the technology, product, or process level). Liddell holds a BS and MS in mechanical engineering and a PhD in materials science, all from the Univ. of Rochester. She completed her postdoctoral training at the U.S. Naval Research Laboratory.